Migrate tests to AssertJ

Mostly thanks to IDEA's plugin: https://plugins.jetbrains.com/plugin/10345-assertions2assertj
There is still a lot of work to do when complex and composite matchers are used.

* Add `awaitility` dependency and deprecate `EventuallyMatcher` in favor
of `awaitility`
* Remove Hamcrest from dependencies and disable JUnit & Hamcrest
static imports to encourage to use only AssertJ
* Migrate JUnit assumptions in rules to AssertJ's assumptions
* Deprecate some custom matchers in favor of existing in Hamcrest
after upgrading the last to version `2.1`
* Replace `ExpectedException` rules with `assertThatThrownBy()`
* Mention `MessagePredicate` in the `testing.adoc`

spring-integration-core/src/test/java/org/springframework/integration/aggregator/AbstractCorrelatingMessageHandlerTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2018 the original author or authors.
+ * Copyright 2002-2019 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -16,11 +16,7 @@
 
 package org.springframework.integration.aggregator;
 
-import static org.junit.Assert.assertEquals;
-import static org.junit.Assert.assertFalse;
-import static org.junit.Assert.assertNotNull;
-import static org.junit.Assert.assertNull;
-import static org.junit.Assert.assertTrue;
+import static org.assertj.core.api.Assertions.assertThat;
 import static org.mockito.Mockito.never;
 import static org.mockito.Mockito.spy;
 import static org.mockito.Mockito.verify;
@@ -139,15 +135,15 @@ public class AbstractCorrelatingMessageHandlerTests {
 				.build();
 		handler.handleMessage(message);
 
-		assertTrue(waitReapCompleteLatch.await(20, TimeUnit.SECONDS));
+		assertThat(waitReapCompleteLatch.await(20, TimeUnit.SECONDS)).isTrue();
 		// Before INT-2751 we got bar + bar + qux
-		assertEquals(2, outputMessages.size()); // bar + qux
+		assertThat(outputMessages.size()).isEqualTo(2); // bar + qux
 		// normal release
-		assertEquals(2, ((MessageGroup) outputMessages.get(0).getPayload()).size()); // 'bar'
+		assertThat(((MessageGroup) outputMessages.get(0).getPayload()).size()).isEqualTo(2); // 'bar'
 		// reaper release
-		assertEquals(1, ((MessageGroup) outputMessages.get(1).getPayload()).size()); // 'qux'
+		assertThat(((MessageGroup) outputMessages.get(1).getPayload()).size()).isEqualTo(1); // 'qux'
 
-		assertNull(discards.receive(0));
+		assertThat(discards.receive(0)).isNull();
 		exec.shutdownNow();
 	}
 
@@ -171,11 +167,13 @@ public class AbstractCorrelatingMessageHandlerTests {
 				.build();
 		handler.handleMessage(message);
 
-		assertEquals(1, outputMessages.size());
+		assertThat(outputMessages.size()).isEqualTo(1);
 
-		assertEquals(1, TestUtils.getPropertyValue(handler, "messageStore.groupIdToMessageGroup", Map.class).size());
+		assertThat(TestUtils.getPropertyValue(handler, "messageStore.groupIdToMessageGroup", Map.class).size())
+				.isEqualTo(1);
 		groupStore.expireMessageGroups(0);
-		assertEquals(0, TestUtils.getPropertyValue(handler, "messageStore.groupIdToMessageGroup", Map.class).size());
+		assertThat(TestUtils.getPropertyValue(handler, "messageStore.groupIdToMessageGroup", Map.class).size())
+				.isEqualTo(0);
 	}
 
 	@Test // INT-2833
@@ -200,11 +198,13 @@ public class AbstractCorrelatingMessageHandlerTests {
 
 		handler.setMinimumTimeoutForEmptyGroups(10_000);
 
-		assertEquals(1, outputMessages.size());
+		assertThat(outputMessages.size()).isEqualTo(1);
 
-		assertEquals(1, TestUtils.getPropertyValue(handler, "messageStore.groupIdToMessageGroup", Map.class).size());
+		assertThat(TestUtils.getPropertyValue(handler, "messageStore.groupIdToMessageGroup", Map.class).size())
+				.isEqualTo(1);
 		groupStore.expireMessageGroups(0);
-		assertEquals(1, TestUtils.getPropertyValue(handler, "messageStore.groupIdToMessageGroup", Map.class).size());
+		assertThat(TestUtils.getPropertyValue(handler, "messageStore.groupIdToMessageGroup", Map.class).size())
+				.isEqualTo(1);
 
 		handler.setMinimumTimeoutForEmptyGroups(10);
 
@@ -220,8 +220,9 @@ public class AbstractCorrelatingMessageHandlerTests {
 			}
 		}
 
-		assertTrue(n < 200);
-		assertEquals(0, TestUtils.getPropertyValue(handler, "messageStore.groupIdToMessageGroup", Map.class).size());
+		assertThat(n < 200).isTrue();
+		assertThat(TestUtils.getPropertyValue(handler, "messageStore.groupIdToMessageGroup", Map.class).size())
+				.isEqualTo(0);
 	}
 
 	@Test
@@ -245,9 +246,9 @@ public class AbstractCorrelatingMessageHandlerTests {
 		new DirectFieldAccessor(group).setPropertyValue("lastModified", groupNow.getLastModified());
 		forceComplete.invoke(handler, group);
 		Message<?> message = outputChannel.receive(0);
-		assertNotNull(message);
+		assertThat(message).isNotNull();
 		Collection<?> payload = (Collection<?>) message.getPayload();
-		assertEquals(1, payload.size());
+		assertThat(payload.size()).isEqualTo(1);
 	}
 
 	@Test /* INT-3216 */
@@ -267,10 +268,10 @@ public class AbstractCorrelatingMessageHandlerTests {
 		forceComplete.setAccessible(true);
 		MessageGroup group = (MessageGroup) TestUtils.getPropertyValue(mgs, "groupIdToMessageGroup", Map.class)
 				.get("foo");
-		assertTrue(group.isComplete());
+		assertThat(group.isComplete()).isTrue();
 		forceComplete.invoke(handler, group);
 		verify(mgs, never()).getMessageGroup("foo");
-		assertNull(outputChannel.receive(0));
+		assertThat(outputChannel.receive(0)).isNull();
 	}
 
 	/*
@@ -294,12 +295,12 @@ public class AbstractCorrelatingMessageHandlerTests {
 		forceComplete.setAccessible(true);
 		MessageGroup groupInStore = (MessageGroup) TestUtils.getPropertyValue(mgs, "groupIdToMessageGroup", Map.class)
 				.get("foo");
-		assertTrue(groupInStore.isComplete());
-		assertFalse(group.isComplete());
+		assertThat(groupInStore.isComplete()).isTrue();
+		assertThat(group.isComplete()).isFalse();
 		new DirectFieldAccessor(group).setPropertyValue("lastModified", groupInStore.getLastModified());
 		forceComplete.invoke(handler, group);
 		verify(mgs).getMessageGroup("foo");
-		assertNull(outputChannel.receive(0));
+		assertThat(outputChannel.receive(0)).isNull();
 	}
 
 	/*
@@ -322,14 +323,14 @@ public class AbstractCorrelatingMessageHandlerTests {
 		forceComplete.setAccessible(true);
 		MessageGroup groupInStore = (MessageGroup) TestUtils.getPropertyValue(mgs, "groupIdToMessageGroup", Map.class)
 				.get("foo");
-		assertFalse(groupInStore.isComplete());
-		assertFalse(group.isComplete());
+		assertThat(groupInStore.isComplete()).isFalse();
+		assertThat(group.isComplete()).isFalse();
 		DirectFieldAccessor directFieldAccessor = new DirectFieldAccessor(group);
 		directFieldAccessor.setPropertyValue("lastModified", groupInStore.getLastModified());
 		directFieldAccessor.setPropertyValue("timestamp", groupInStore.getTimestamp() - 1);
 		forceComplete.invoke(handler, group);
 		verify(mgs).getMessageGroup("foo");
-		assertNull(outputChannel.receive(0));
+		assertThat(outputChannel.receive(0)).isNull();
 	}
 
 	@Test
@@ -373,13 +374,13 @@ public class AbstractCorrelatingMessageHandlerTests {
 		/* Previously lock for the groupId hasn't been unlocked from the 'forceComplete', because it wasn't
 		 reachable in case of exception from the BasicMessageGroupStore.removeMessageGroup
 		  */
-		assertTrue(executorService.awaitTermination(10, TimeUnit.SECONDS));
+		assertThat(executorService.awaitTermination(10, TimeUnit.SECONDS)).isTrue();
 
 		/* Since MessageGroup had been marked as 'complete', but hasn't been removed because of exception,
 		 the second message is discarded
 		  */
 		Message<?> receive = discardChannel.receive(10000);
-		assertNotNull(receive);
+		assertThat(receive).isNotNull();
 	}
 
 	@Test
@@ -409,9 +410,10 @@ public class AbstractCorrelatingMessageHandlerTests {
 				.build();
 		handler.handleMessage(message);
 
-		assertEquals(1, outputMessages.size());
+		assertThat(outputMessages.size()).isEqualTo(1);
 
-		assertEquals(1, TestUtils.getPropertyValue(handler, "messageStore.groupIdToMessageGroup", Map.class).size());
+		assertThat(TestUtils.getPropertyValue(handler, "messageStore.groupIdToMessageGroup", Map.class).size())
+				.isEqualTo(1);
 
 		Thread.sleep(100);
 
@@ -422,8 +424,9 @@ public class AbstractCorrelatingMessageHandlerTests {
 			Thread.sleep(50);
 		}
 
-		assertTrue(n < 200);
-		assertEquals(0, TestUtils.getPropertyValue(handler, "messageStore.groupIdToMessageGroup", Map.class).size());
+		assertThat(n < 200).isTrue();
+		assertThat(TestUtils.getPropertyValue(handler, "messageStore.groupIdToMessageGroup", Map.class).size())
+				.isEqualTo(0);
 	}
 
 	@Test
@@ -449,8 +452,8 @@ public class AbstractCorrelatingMessageHandlerTests {
 
 		groupStore.expireMessageGroups(0);
 
-		assertEquals(2, handler1DiscardChannel.getQueueSize());
-		assertEquals(1, handler2DiscardChannel.getQueueSize());
+		assertThat(handler1DiscardChannel.getQueueSize()).isEqualTo(2);
+		assertThat(handler2DiscardChannel.getQueueSize()).isEqualTo(1);
 	}
 
 	@Test
@@ -473,12 +476,12 @@ public class AbstractCorrelatingMessageHandlerTests {
 
 		Message<?> receive = outputChannel.receive(10_000);
 
-		assertNotNull(receive);
+		assertThat(receive).isNotNull();
 
-		assertEquals(2, receive.getHeaders().get(IntegrationMessageHeaderAccessor.CORRELATION_ID));
-		assertEquals(2, receive.getHeaders().get(IntegrationMessageHeaderAccessor.SEQUENCE_NUMBER));
-		assertEquals(2, receive.getHeaders().get(IntegrationMessageHeaderAccessor.SEQUENCE_SIZE));
-		assertTrue(receive.getHeaders().containsKey(IntegrationMessageHeaderAccessor.SEQUENCE_DETAILS));
+		assertThat(receive.getHeaders().get(IntegrationMessageHeaderAccessor.CORRELATION_ID)).isEqualTo(2);
+		assertThat(receive.getHeaders().get(IntegrationMessageHeaderAccessor.SEQUENCE_NUMBER)).isEqualTo(2);
+		assertThat(receive.getHeaders().get(IntegrationMessageHeaderAccessor.SEQUENCE_SIZE)).isEqualTo(2);
+		assertThat(receive.getHeaders().containsKey(IntegrationMessageHeaderAccessor.SEQUENCE_DETAILS)).isTrue();
 	}
 
 }

spring-integration-core/src/test/java/org/springframework/integration/aggregator/AggregatingMessageGroupProcessorHeaderTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2018 the original author or authors.
+ * Copyright 2002-2019 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -16,10 +16,7 @@
 
 package org.springframework.integration.aggregator;
 
-import static org.junit.Assert.assertEquals;
-import static org.junit.Assert.assertNotNull;
-import static org.junit.Assert.assertNull;
-import static org.junit.Assert.assertTrue;
+import static org.assertj.core.api.Assertions.assertThat;
 import static org.mockito.Mockito.mock;
 
 import java.util.Arrays;
@@ -133,11 +130,11 @@ public class AggregatingMessageGroupProcessorHeaderTests {
 		List<Message<?>> messages = Arrays.asList(message1, message2);
 		MessageGroup group = new SimpleMessageGroup(messages, 1);
 		Object result = processor.processMessageGroup(group);
-		assertNotNull(result);
-		assertTrue(result instanceof AbstractIntegrationMessageBuilder<?>);
+		assertThat(result).isNotNull();
+		assertThat(result instanceof AbstractIntegrationMessageBuilder<?>).isTrue();
 		Message<?> resultMessage = ((AbstractIntegrationMessageBuilder<?>) result).build();
-		assertNull(resultMessage.getHeaders().get("k1"));
-		assertNull(resultMessage.getHeaders().get("k2"));
+		assertThat(resultMessage.getHeaders().get("k1")).isNull();
+		assertThat(resultMessage.getHeaders().get("k2")).isNull();
 
 		headers1 = new HashMap<>();
 		headers1.put("k1", "foo");
@@ -156,8 +153,8 @@ public class AggregatingMessageGroupProcessorHeaderTests {
 		group = new SimpleMessageGroup(messages, 1);
 		result = processor.processMessageGroup(group);
 		resultMessage = ((AbstractIntegrationMessageBuilder<?>) result).build();
-		assertNull(resultMessage.getHeaders().get("k1"));
-		assertNull(resultMessage.getHeaders().get("k2"));
+		assertThat(resultMessage.getHeaders().get("k1")).isNull();
+		assertThat(resultMessage.getHeaders().get("k2")).isNull();
 	}
 
 
@@ -169,11 +166,11 @@ public class AggregatingMessageGroupProcessorHeaderTests {
 		List<Message<?>> messages = Collections.singletonList(message);
 		MessageGroup group = new SimpleMessageGroup(messages, 1);
 		Object result = processor.processMessageGroup(group);
-		assertNotNull(result);
-		assertTrue(result instanceof AbstractIntegrationMessageBuilder<?>);
+		assertThat(result).isNotNull();
+		assertThat(result instanceof AbstractIntegrationMessageBuilder<?>).isTrue();
 		Message<?> resultMessage = ((AbstractIntegrationMessageBuilder<?>) result).build();
-		assertEquals("value1", resultMessage.getHeaders().get("k1"));
-		assertEquals(2, resultMessage.getHeaders().get("k2"));
+		assertThat(resultMessage.getHeaders().get("k1")).isEqualTo("value1");
+		assertThat(resultMessage.getHeaders().get("k2")).isEqualTo(2);
 	}
 
 	private void twoMessagesWithoutConflicts(MessageGroupProcessor processor) {
@@ -185,11 +182,11 @@ public class AggregatingMessageGroupProcessorHeaderTests {
 		List<Message<?>> messages = Arrays.asList(message1, message2);
 		MessageGroup group = new SimpleMessageGroup(messages, 1);
 		Object result = processor.processMessageGroup(group);
-		assertNotNull(result);
-		assertTrue(result instanceof AbstractIntegrationMessageBuilder<?>);
+		assertThat(result).isNotNull();
+		assertThat(result instanceof AbstractIntegrationMessageBuilder<?>).isTrue();
 		Message<?> resultMessage = ((AbstractIntegrationMessageBuilder<?>) result).build();
-		assertEquals("value1", resultMessage.getHeaders().get("k1"));
-		assertEquals(2, resultMessage.getHeaders().get("k2"));
+		assertThat(resultMessage.getHeaders().get("k1")).isEqualTo("value1");
+		assertThat(resultMessage.getHeaders().get("k2")).isEqualTo(2);
 	}
 
 	private void twoMessagesWithConflicts(MessageGroupProcessor processor) {
@@ -204,11 +201,11 @@ public class AggregatingMessageGroupProcessorHeaderTests {
 		List<Message<?>> messages = Arrays.asList(message1, message2);
 		MessageGroup group = new SimpleMessageGroup(messages, 1);
 		Object result = processor.processMessageGroup(group);
-		assertNotNull(result);
-		assertTrue(result instanceof AbstractIntegrationMessageBuilder<?>);
+		assertThat(result).isNotNull();
+		assertThat(result instanceof AbstractIntegrationMessageBuilder<?>).isTrue();
 		Message<?> resultMessage = ((AbstractIntegrationMessageBuilder<?>) result).build();
-		assertNull(resultMessage.getHeaders().get("k1"));
-		assertEquals(123, resultMessage.getHeaders().get("k2"));
+		assertThat(resultMessage.getHeaders().get("k1")).isNull();
+		assertThat(resultMessage.getHeaders().get("k2")).isEqualTo(123);
 	}
 
 	private void missingValuesDoNotConflict(MessageGroupProcessor processor) {
@@ -235,17 +232,17 @@ public class AggregatingMessageGroupProcessorHeaderTests {
 		List<Message<?>> messages = Arrays.asList(message1, message2, message3);
 		MessageGroup group = new SimpleMessageGroup(messages, 1);
 		Object result = processor.processMessageGroup(group);
-		assertNotNull(result);
-		assertTrue(result instanceof AbstractIntegrationMessageBuilder<?>);
+		assertThat(result).isNotNull();
+		assertThat(result instanceof AbstractIntegrationMessageBuilder<?>).isTrue();
 		Message<?> resultMessage = ((AbstractIntegrationMessageBuilder<?>) result).build();
-		assertEquals("value1", resultMessage.getHeaders().get("only1"));
-		assertEquals("value2", resultMessage.getHeaders().get("only2"));
-		assertEquals("value3", resultMessage.getHeaders().get("only3"));
-		assertEquals("foo", resultMessage.getHeaders().get("commonTo1And2"));
-		assertEquals("bar", resultMessage.getHeaders().get("commonTo2And3"));
-		assertEquals(123, resultMessage.getHeaders().get("commonToAll"));
-		assertNull(resultMessage.getHeaders().get("conflictBetween1And2"));
-		assertNull(resultMessage.getHeaders().get("conflictBetween2And3"));
+		assertThat(resultMessage.getHeaders().get("only1")).isEqualTo("value1");
+		assertThat(resultMessage.getHeaders().get("only2")).isEqualTo("value2");
+		assertThat(resultMessage.getHeaders().get("only3")).isEqualTo("value3");
+		assertThat(resultMessage.getHeaders().get("commonTo1And2")).isEqualTo("foo");
+		assertThat(resultMessage.getHeaders().get("commonTo2And3")).isEqualTo("bar");
+		assertThat(resultMessage.getHeaders().get("commonToAll")).isEqualTo(123);
+		assertThat(resultMessage.getHeaders().get("conflictBetween1And2")).isNull();
+		assertThat(resultMessage.getHeaders().get("conflictBetween2And3")).isNull();
 	}
 
 	private void multipleValuesConflict(MessageGroupProcessor processor) {
@@ -264,11 +261,11 @@ public class AggregatingMessageGroupProcessorHeaderTests {
 		List<Message<?>> messages = Arrays.asList(message1, message2, message3);
 		MessageGroup group = new SimpleMessageGroup(messages, 1);
 		Object result = processor.processMessageGroup(group);
-		assertNotNull(result);
-		assertTrue(result instanceof AbstractIntegrationMessageBuilder<?>);
+		assertThat(result).isNotNull();
+		assertThat(result instanceof AbstractIntegrationMessageBuilder<?>).isTrue();
 		Message<?> resultMessage = ((AbstractIntegrationMessageBuilder<?>) result).build();
-		assertEquals("valueForAll", resultMessage.getHeaders().get("common"));
-		assertNull(resultMessage.getHeaders().get("conflict"));
+		assertThat(resultMessage.getHeaders().get("common")).isEqualTo("valueForAll");
+		assertThat(resultMessage.getHeaders().get("conflict")).isNull();
 	}
 
 	private static Message<?> correlatedMessage(Object correlationId, Integer sequenceSize,

spring-integration-core/src/test/java/org/springframework/integration/aggregator/AggregatorTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2018 the original author or authors.
+ * Copyright 2002-2019 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -16,15 +16,7 @@
 
 package org.springframework.integration.aggregator;
 
-import static org.hamcrest.CoreMatchers.is;
-import static org.hamcrest.Matchers.lessThan;
-import static org.junit.Assert.assertEquals;
-import static org.junit.Assert.assertFalse;
-import static org.junit.Assert.assertNotNull;
-import static org.junit.Assert.assertNull;
-import static org.junit.Assert.assertSame;
-import static org.junit.Assert.assertThat;
-import static org.junit.Assert.assertTrue;
+import static org.assertj.core.api.Assertions.assertThat;
 import static org.mockito.Mockito.mock;
 
 import java.util.ArrayList;
@@ -132,8 +124,8 @@ public class AggregatorTests {
 				" (10k in " + stopwatch.getLastTaskTimeMillis() + "ms)");
 
 		Collection<?> result = resultFuture.get(10, TimeUnit.SECONDS);
-		assertNotNull(result);
-		assertEquals(60000, result.size());
+		assertThat(result).isNotNull();
+		assertThat(result.size()).isEqualTo(60000);
 	}
 
 	@Test
@@ -181,9 +173,9 @@ public class AggregatorTests {
 				" (10k in " + stopwatch.getLastTaskTimeMillis() + "ms)");
 
 		Collection<?> result = resultFuture.get(10, TimeUnit.SECONDS);
-		assertNotNull(result);
-		assertEquals(120000, result.size());
-		assertThat(stopwatch.getTotalTimeSeconds(), lessThan(60.0)); // actually < 2.0, was many minutes
+		assertThat(result).isNotNull();
+		assertThat(result.size()).isEqualTo(120000);
+		assertThat(stopwatch.getTotalTimeSeconds()).isLessThan(60.0); // actually < 2.0, was many minutes
 	}
 
 	@Test
@@ -251,8 +243,8 @@ public class AggregatorTests {
 				" (10k in " + stopwatch.getLastTaskTimeMillis() + "ms)");
 
 		Collection<?> result = resultFuture.get(10, TimeUnit.SECONDS);
-		assertNotNull(result);
-		assertEquals(60000, result.size());
+		assertThat(result).isNotNull();
+		assertThat(result.size()).isEqualTo(60000);
 	}
 
 	@Test
@@ -272,8 +264,8 @@ public class AggregatorTests {
 		this.aggregator.handleMessage(message3);
 
 		Message<?> reply = replyChannel.receive(10000);
-		assertNotNull(reply);
-		assertEquals(reply.getPayload(), 105);
+		assertThat(reply).isNotNull();
+		assertThat(105).isEqualTo(reply.getPayload());
 	}
 
 	@Test
@@ -294,8 +286,8 @@ public class AggregatorTests {
 		this.aggregator.handleMessage(message3);
 
 		Message<?> reply = replyChannel.receive(10000);
-		assertNotNull(reply);
-		assertEquals(reply.getPayload(), 105);
+		assertThat(reply).isNotNull();
+		assertThat(105).isEqualTo(reply.getPayload());
 	}
 
 	@Test
@@ -311,15 +303,15 @@ public class AggregatorTests {
 		this.aggregator.handleMessage(message);
 		this.store.expireMessageGroups(-10000);
 		Message<?> reply = replyChannel.receive(0);
-		assertNull("No message should have been sent normally", reply);
+		assertThat(reply).as("No message should have been sent normally").isNull();
 		Message<?> discardedMessage = discardChannel.receive(1000);
-		assertNotNull("A message should have been discarded", discardedMessage);
-		assertEquals(message, discardedMessage);
-		assertEquals(1, expiryEvents.size());
-		assertSame(this.aggregator, expiryEvents.get(0).getSource());
-		assertEquals("ABC", this.expiryEvents.get(0).getGroupId());
-		assertEquals(1, this.expiryEvents.get(0).getMessageCount());
-		assertTrue(this.expiryEvents.get(0).isDiscarded());
+		assertThat(discardedMessage).as("A message should have been discarded").isNotNull();
+		assertThat(discardedMessage).isEqualTo(message);
+		assertThat(expiryEvents.size()).isEqualTo(1);
+		assertThat(expiryEvents.get(0).getSource()).isSameAs(this.aggregator);
+		assertThat(this.expiryEvents.get(0).getGroupId()).isEqualTo("ABC");
+		assertThat(this.expiryEvents.get(0).getMessageCount()).isEqualTo(1);
+		assertThat(this.expiryEvents.get(0).isDiscarded()).isTrue();
 	}
 
 	@Test
@@ -336,15 +328,15 @@ public class AggregatorTests {
 		this.aggregator.handleMessage(message);
 		this.store.expireMessageGroups(-10000);
 		Message<?> reply = replyChannel.receive(0);
-		assertNull("No message should have been sent normally", reply);
+		assertThat(reply).as("No message should have been sent normally").isNull();
 		Message<?> discardedMessage = discardChannel.receive(1000);
-		assertNotNull("A message should have been discarded", discardedMessage);
-		assertEquals(message, discardedMessage);
-		assertEquals(1, expiryEvents.size());
-		assertSame(this.aggregator, expiryEvents.get(0).getSource());
-		assertEquals("ABC", this.expiryEvents.get(0).getGroupId());
-		assertEquals(1, this.expiryEvents.get(0).getMessageCount());
-		assertTrue(this.expiryEvents.get(0).isDiscarded());
+		assertThat(discardedMessage).as("A message should have been discarded").isNotNull();
+		assertThat(discardedMessage).isEqualTo(message);
+		assertThat(expiryEvents.size()).isEqualTo(1);
+		assertThat(expiryEvents.get(0).getSource()).isSameAs(this.aggregator);
+		assertThat(this.expiryEvents.get(0).getGroupId()).isEqualTo("ABC");
+		assertThat(this.expiryEvents.get(0).getMessageCount()).isEqualTo(1);
+		assertThat(this.expiryEvents.get(0).isDiscarded()).isTrue();
 	}
 
 	@Test
@@ -357,16 +349,16 @@ public class AggregatorTests {
 		this.aggregator.handleMessage(message2);
 		this.store.expireMessageGroups(-10000);
 		Message<?> reply = replyChannel.receive(1000);
-		assertNotNull("A reply message should have been received", reply);
-		assertEquals(15, reply.getPayload());
-		assertEquals(1, expiryEvents.size());
-		assertSame(this.aggregator, expiryEvents.get(0).getSource());
-		assertEquals("ABC", this.expiryEvents.get(0).getGroupId());
-		assertEquals(2, this.expiryEvents.get(0).getMessageCount());
-		assertFalse(this.expiryEvents.get(0).isDiscarded());
+		assertThat(reply).as("A reply message should have been received").isNotNull();
+		assertThat(reply.getPayload()).isEqualTo(15);
+		assertThat(expiryEvents.size()).isEqualTo(1);
+		assertThat(expiryEvents.get(0).getSource()).isSameAs(this.aggregator);
+		assertThat(this.expiryEvents.get(0).getGroupId()).isEqualTo("ABC");
+		assertThat(this.expiryEvents.get(0).getMessageCount()).isEqualTo(2);
+		assertThat(this.expiryEvents.get(0).isDiscarded()).isFalse();
 		Message<?> message3 = createMessage(5, "ABC", 3, 3, replyChannel, null);
 		this.aggregator.handleMessage(message3);
-		assertEquals(1, this.store.getMessageGroup("ABC").size());
+		assertThat(this.store.getMessageGroup("ABC").size()).isEqualTo(1);
 	}
 
 	@Test
@@ -391,20 +383,20 @@ public class AggregatorTests {
 		this.aggregator.handleMessage(message2);
 		this.store.expireMessageGroups(-10000);
 		Message<?> reply = replyChannel.receive(1000);
-		assertNotNull("A reply message should have been received", reply);
-		assertEquals(15, reply.getPayload());
-		assertEquals(1, expiryEvents.size());
-		assertSame(this.aggregator, expiryEvents.get(0).getSource());
-		assertEquals("ABC", this.expiryEvents.get(0).getGroupId());
-		assertEquals(2, this.expiryEvents.get(0).getMessageCount());
-		assertFalse(this.expiryEvents.get(0).isDiscarded());
-		assertEquals(0, this.store.getMessageGroup("ABC").size());
+		assertThat(reply).as("A reply message should have been received").isNotNull();
+		assertThat(reply.getPayload()).isEqualTo(15);
+		assertThat(expiryEvents.size()).isEqualTo(1);
+		assertThat(expiryEvents.get(0).getSource()).isSameAs(this.aggregator);
+		assertThat(this.expiryEvents.get(0).getGroupId()).isEqualTo("ABC");
+		assertThat(this.expiryEvents.get(0).getMessageCount()).isEqualTo(2);
+		assertThat(this.expiryEvents.get(0).isDiscarded()).isFalse();
+		assertThat(this.store.getMessageGroup("ABC").size()).isEqualTo(0);
 		Message<?> message3 = createMessage(5, "ABC", 3, 3, lockCheckingChannel, null);
 		this.aggregator.handleMessage(message3);
-		assertEquals(0, this.store.getMessageGroup("ABC").size());
+		assertThat(this.store.getMessageGroup("ABC").size()).isEqualTo(0);
 		Message<?> discardedMessage = discardChannel.receive(1000);
-		assertNotNull("A message should have been discarded", discardedMessage);
-		assertSame(message3, discardedMessage);
+		assertThat(discardedMessage).as("A message should have been discarded").isNotNull();
+		assertThat(discardedMessage).isSameAs(message3);
 	}
 
 	@Test
@@ -430,20 +422,20 @@ public class AggregatorTests {
 		this.aggregator.handleMessage(message2);
 		this.store.expireMessageGroups(-10000);
 		Message<?> reply = replyChannel.receive(1000);
-		assertNotNull("A reply message should have been received", reply);
-		assertEquals(15, reply.getPayload());
-		assertEquals(1, expiryEvents.size());
-		assertSame(this.aggregator, expiryEvents.get(0).getSource());
-		assertEquals("ABC", this.expiryEvents.get(0).getGroupId());
-		assertEquals(2, this.expiryEvents.get(0).getMessageCount());
-		assertFalse(this.expiryEvents.get(0).isDiscarded());
-		assertEquals(0, this.store.getMessageGroup("ABC").size());
+		assertThat(reply).as("A reply message should have been received").isNotNull();
+		assertThat(reply.getPayload()).isEqualTo(15);
+		assertThat(expiryEvents.size()).isEqualTo(1);
+		assertThat(expiryEvents.get(0).getSource()).isSameAs(this.aggregator);
+		assertThat(this.expiryEvents.get(0).getGroupId()).isEqualTo("ABC");
+		assertThat(this.expiryEvents.get(0).getMessageCount()).isEqualTo(2);
+		assertThat(this.expiryEvents.get(0).isDiscarded()).isFalse();
+		assertThat(this.store.getMessageGroup("ABC").size()).isEqualTo(0);
 		Message<?> message3 = createMessage(5, "ABC", 3, 3, lockCheckingChannel, null);
 		this.aggregator.handleMessage(message3);
-		assertEquals(0, this.store.getMessageGroup("ABC").size());
+		assertThat(this.store.getMessageGroup("ABC").size()).isEqualTo(0);
 		Message<?> discardedMessage = discardChannel.receive(1000);
-		assertNotNull("A message should have been discarded", discardedMessage);
-		assertSame(message3, discardedMessage);
+		assertThat(discardedMessage).as("A message should have been discarded").isNotNull();
+		assertThat(discardedMessage).isSameAs(message3);
 	}
 
 	@Test
@@ -464,12 +456,12 @@ public class AggregatorTests {
 		aggregator.handleMessage(message2);
 		@SuppressWarnings("unchecked")
 		Message<Integer> reply1 = (Message<Integer>) replyChannel1.receive(1000);
-		assertNotNull(reply1);
-		assertThat(reply1.getPayload(), is(105));
+		assertThat(reply1).isNotNull();
+		assertThat(reply1.getPayload()).isEqualTo(105);
 		@SuppressWarnings("unchecked")
 		Message<Integer> reply2 = (Message<Integer>) replyChannel2.receive(1000);
-		assertNotNull(reply2);
-		assertThat(reply2.getPayload(), is(2431));
+		assertThat(reply2).isNotNull();
+		assertThat(reply2.getPayload()).isEqualTo(2431);
 	}
 
 	@Test
@@ -481,14 +473,14 @@ public class AggregatorTests {
 
 		this.aggregator.setDiscardChannel(discardChannel);
 		this.aggregator.handleMessage(createMessage(1, 1, 1, 1, replyChannel, null));
-		assertEquals(1, replyChannel.receive(1000).getPayload());
+		assertThat(replyChannel.receive(1000).getPayload()).isEqualTo(1);
 		this.aggregator.handleMessage(createMessage(3, 2, 1, 1, replyChannel, null));
-		assertEquals(3, replyChannel.receive(1000).getPayload());
+		assertThat(replyChannel.receive(1000).getPayload()).isEqualTo(3);
 		this.aggregator.handleMessage(createMessage(4, 3, 1, 1, replyChannel, null));
-		assertEquals(4, replyChannel.receive(1000).getPayload());
+		assertThat(replyChannel.receive(1000).getPayload()).isEqualTo(4);
 		// next message with same correllation ID is discarded
 		this.aggregator.handleMessage(createMessage(2, 1, 1, 1, replyChannel, null));
-		assertEquals(2, discardChannel.receive(1000).getPayload());
+		assertThat(discardChannel.receive(1000).getPayload()).isEqualTo(2);
 	}
 
 	@Test
@@ -500,16 +492,16 @@ public class AggregatorTests {
 
 		this.aggregator.setDiscardChannel(discardChannel);
 		this.aggregator.handleMessage(createMessage(1, 1, 1, 1, replyChannel, null));
-		assertEquals(1, replyChannel.receive(1000).getPayload());
+		assertThat(replyChannel.receive(1000).getPayload()).isEqualTo(1);
 		this.aggregator.handleMessage(createMessage(2, 2, 1, 1, replyChannel, null));
-		assertEquals(2, replyChannel.receive(1000).getPayload());
+		assertThat(replyChannel.receive(1000).getPayload()).isEqualTo(2);
 		this.aggregator.handleMessage(createMessage(3, 3, 1, 1, replyChannel, null));
-		assertEquals(3, replyChannel.receive(1000).getPayload());
+		assertThat(replyChannel.receive(1000).getPayload()).isEqualTo(3);
 		this.aggregator.handleMessage(createMessage(4, 4, 1, 1, replyChannel, null));
-		assertEquals(4, replyChannel.receive(1000).getPayload());
+		assertThat(replyChannel.receive(1000).getPayload()).isEqualTo(4);
 		this.aggregator.handleMessage(createMessage(5, 1, 1, 1, replyChannel, null));
-		assertEquals(5, replyChannel.receive(1000).getPayload());
-		assertNull(discardChannel.receive(0));
+		assertThat(replyChannel.receive(1000).getPayload()).isEqualTo(5);
+		assertThat(discardChannel.receive(0)).isNull();
 	}
 
 	@Test(expected = MessageHandlingException.class)
@@ -532,8 +524,8 @@ public class AggregatorTests {
 		this.aggregator.handleMessage(message4);
 
 		Message<?> reply = replyChannel.receive(10000);
-		assertNotNull("A message should be aggregated", reply);
-		assertThat((reply.getPayload()), is(105));
+		assertThat(reply).as("A message should be aggregated").isNotNull();
+		assertThat((reply.getPayload())).isEqualTo(105);
 	}
 
 	@Test
@@ -552,8 +544,8 @@ public class AggregatorTests {
 		this.aggregator.handleMessage(message2);
 
 		Message<?> reply = replyChannel.receive(10000);
-		assertNotNull("A message should be aggregated", reply);
-		assertThat((reply.getPayload()), is(105));
+		assertThat(reply).as("A message should be aggregated").isNotNull();
+		assertThat((reply.getPayload())).isEqualTo(105);
 	}
 
 
@@ -570,7 +562,7 @@ public class AggregatorTests {
 	private void checkLock(AbstractCorrelatingMessageHandler handler, String group, boolean expectedHeld) {
 		ReentrantLock lock = (ReentrantLock) TestUtils.getPropertyValue(handler, "lockRegistry", LockRegistry.class)
 				.obtain(UUIDConverter.getUUID(group).toString());
-		assertEquals(expectedHeld, lock.isHeldByCurrentThread());
+		assertThat(lock.isHeldByCurrentThread()).isEqualTo(expectedHeld);
 	}
 
 	private class MultiplyingProcessor implements MessageGroupProcessor {

spring-integration-core/src/test/java/org/springframework/integration/aggregator/BarrierMessageHandlerTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2015-2018 the original author or authors.
+ * Copyright 2015-2019 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -16,15 +16,8 @@
 
 package org.springframework.integration.aggregator;
 
-import static org.hamcrest.Matchers.allOf;
-import static org.hamcrest.Matchers.containsString;
-import static org.hamcrest.Matchers.startsWith;
-import static org.junit.Assert.assertEquals;
-import static org.junit.Assert.assertNotNull;
-import static org.junit.Assert.assertSame;
-import static org.junit.Assert.assertThat;
-import static org.junit.Assert.assertTrue;
-import static org.junit.Assert.fail;
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.assertj.core.api.Assertions.fail;
 import static org.mockito.Mockito.mock;
 import static org.mockito.Mockito.spy;
 import static org.mockito.Mockito.verify;
@@ -39,7 +32,6 @@ import java.util.concurrent.TimeUnit;
 import java.util.concurrent.atomic.AtomicReference;
 
 import org.apache.commons.logging.Log;
-import org.hamcrest.Matchers;
 import org.junit.Test;
 import org.junit.runner.RunWith;
 import org.mockito.ArgumentCaptor;
@@ -121,19 +113,19 @@ public class BarrierMessageHandlerTests {
 			Thread.sleep(100);
 		}
 		Map<?, ?> inProcess = TestUtils.getPropertyValue(handler, "inProcess", Map.class);
-		assertEquals(1, inProcess.size());
-		assertTrue("suspension did not appear in time", n < 100);
-		assertTrue(latch.await(10, TimeUnit.SECONDS));
-		assertNotNull(dupCorrelation.get());
-		assertThat(dupCorrelation.get().getMessage(), startsWith("Correlation key (foo) is already in use by"));
+		assertThat(inProcess.size()).isEqualTo(1);
+		assertThat(n < 100).as("suspension did not appear in time").isTrue();
+		assertThat(latch.await(10, TimeUnit.SECONDS)).isTrue();
+		assertThat(dupCorrelation.get()).isNotNull();
+		assertThat(dupCorrelation.get().getMessage()).startsWith("Correlation key (foo) is already in use by");
 		handler.trigger(MessageBuilder.withPayload("bar").setCorrelationId("foo").build());
 		Message<?> received = outputChannel.receive(10000);
-		assertNotNull(received);
+		assertThat(received).isNotNull();
 		List<?> result = (List<?>) received.getPayload();
-		assertEquals("foo", result.get(0));
-		assertEquals("bar", result.get(1));
-		assertEquals(0, suspensions.size());
-		assertEquals(0, inProcess.size());
+		assertThat(result.get(0)).isEqualTo("foo");
+		assertThat(result.get(1)).isEqualTo("bar");
+		assertThat(suspensions.size()).isEqualTo(0);
+		assertThat(inProcess.size()).isEqualTo(0);
 		exec.shutdownNow();
 	}
 
@@ -151,14 +143,14 @@ public class BarrierMessageHandlerTests {
 		while (n++ < 100 && suspensions.size() == 0) {
 			Thread.sleep(100);
 		}
-		assertTrue("suspension did not appear in time", n < 100);
+		assertThat(n < 100).as("suspension did not appear in time").isTrue();
 		handler.handleMessage(MessageBuilder.withPayload("foo").setCorrelationId("foo").build());
 		Message<?> received = outputChannel.receive(10000);
-		assertNotNull(received);
+		assertThat(received).isNotNull();
 		List<?> result = (ArrayList<?>) received.getPayload();
-		assertEquals("foo", result.get(0));
-		assertEquals("bar", result.get(1));
-		assertEquals(0, suspensions.size());
+		assertThat(result.get(0)).isEqualTo("foo");
+		assertThat(result.get(1)).isEqualTo("bar");
+		assertThat(suspensions.size()).isEqualTo(0);
 		exec.shutdownNow();
 	}
 
@@ -179,22 +171,21 @@ public class BarrierMessageHandlerTests {
 			latch.countDown();
 		});
 		Map<?, ?> suspensions = TestUtils.getPropertyValue(handler, "suspensions", Map.class);
-		assertTrue(latch.await(10, TimeUnit.SECONDS));
-		assertEquals("suspension not removed", 0, suspensions.size());
+		assertThat(latch.await(10, TimeUnit.SECONDS)).isTrue();
+		assertThat(suspensions.size()).as("suspension not removed").isEqualTo(0);
 		Log logger = spy(TestUtils.getPropertyValue(handler, "logger", Log.class));
 		new DirectFieldAccessor(handler).setPropertyValue("logger", logger);
 		final Message<String> triggerMessage = MessageBuilder.withPayload("bar").setCorrelationId("foo").build();
 		handler.trigger(triggerMessage);
 		ArgumentCaptor<String> captor = ArgumentCaptor.forClass(String.class);
 		verify(logger).error(captor.capture());
-		assertThat(captor.getValue(),
-				allOf(containsString("Suspending thread timed out or did not arrive within timeout for:"),
-						containsString("payload=bar")));
-		assertEquals(0, suspensions.size());
+		assertThat(captor.getValue()).contains("Suspending thread timed out or did not arrive within timeout for:")
+				.contains("payload=bar");
+		assertThat(suspensions.size()).isEqualTo(0);
 		Message<?> discard = discardChannel.receive(0);
-		assertSame(discard, triggerMessage);
+		assertThat(triggerMessage).isSameAs(discard);
 		handler.handleMessage(MessageBuilder.withPayload("foo").setCorrelationId("foo").build());
-		assertEquals(0, suspensions.size());
+		assertThat(suspensions.size()).isEqualTo(0);
 		exec.shutdownNow();
 	}
 
@@ -211,7 +202,7 @@ public class BarrierMessageHandlerTests {
 			fail("exception expected");
 		}
 		catch (Exception e) {
-			assertThat(e, Matchers.instanceOf(ReplyRequiredException.class));
+			assertThat(e).isInstanceOf(ReplyRequiredException.class);
 		}
 	}
 
@@ -239,12 +230,12 @@ public class BarrierMessageHandlerTests {
 		while (n++ < 100 && suspensions.size() == 0) {
 			Thread.sleep(100);
 		}
-		assertTrue("suspension did not appear in time", n < 100);
+		assertThat(n < 100).as("suspension did not appear in time").isTrue();
 		Exception exc = new RuntimeException();
 		handler.trigger(MessageBuilder.withPayload(exc).setCorrelationId("foo").build());
-		assertTrue(latch.await(10, TimeUnit.SECONDS));
-		assertSame(exc, exception.get().getCause());
-		assertEquals(0, suspensions.size());
+		assertThat(latch.await(10, TimeUnit.SECONDS)).isTrue();
+		assertThat(exception.get().getCause()).isSameAs(exc);
+		assertThat(suspensions.size()).isEqualTo(0);
 		exec.shutdownNow();
 	}
 
@@ -255,12 +246,12 @@ public class BarrierMessageHandlerTests {
 		Message<?> suspending = MessageBuilder.withPayload("foo").setCorrelationId("foo").build();
 		this.in.send(suspending);
 		Message<?> out = this.out.receive(10000);
-		assertNotNull(out);
-		assertEquals("[foo, bar]", out.getPayload().toString());
+		assertThat(out).isNotNull();
+		assertThat(out.getPayload().toString()).isEqualTo("[foo, bar]");
 
 		Message<?> publisherMessage = this.publisherChannel.receive(10000);
-		assertNotNull(publisherMessage);
-		assertEquals("BAR", publisherMessage.getPayload());
+		assertThat(publisherMessage).isNotNull();
+		assertThat(publisherMessage.getPayload()).isEqualTo("BAR");
 	}
 
 	@Configuration

spring-integration-core/src/test/java/org/springframework/integration/aggregator/ConcurrentAggregatorTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2018 the original author or authors.
+ * Copyright 2002-2019 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -16,12 +16,7 @@
 
 package org.springframework.integration.aggregator;
 
-import static org.hamcrest.CoreMatchers.is;
-import static org.junit.Assert.assertEquals;
-import static org.junit.Assert.assertNotNull;
-import static org.junit.Assert.assertNull;
-import static org.junit.Assert.assertThat;
-import static org.junit.Assert.assertTrue;
+import static org.assertj.core.api.Assertions.assertThat;
 
 import java.util.concurrent.CountDownLatch;
 import java.util.concurrent.TimeUnit;
@@ -80,12 +75,12 @@ public class ConcurrentAggregatorTests {
 		this.taskExecutor.execute(new AggregatorTestTask(this.aggregator,
 				message3, latch));
 
-		assertTrue(latch.await(10, TimeUnit.SECONDS));
+		assertThat(latch.await(10, TimeUnit.SECONDS)).isTrue();
 
-		assertThat(latch.getCount(), is(0L));
+		assertThat(latch.getCount()).isEqualTo(0L);
 		Message<?> reply = replyChannel.receive(2000);
-		assertNotNull(reply);
-		assertEquals(reply.getPayload(), 105);
+		assertThat(reply).isNotNull();
+		assertThat(105).isEqualTo(reply.getPayload());
 	}
 
 	@Test
@@ -106,8 +101,8 @@ public class ConcurrentAggregatorTests {
 		new AggregatorTestTask(this.aggregator, message2, latch).run();
 		new AggregatorTestTask(this.aggregator, message3, latch).run();
 		Message<?> reply = replyChannel.receive(1000);
-		assertNotNull(reply);
-		assertEquals("123456789", reply.getPayload());
+		assertThat(reply).isNotNull();
+		assertThat(reply.getPayload()).isEqualTo("123456789");
 	}
 
 	@Test
@@ -122,16 +117,16 @@ public class ConcurrentAggregatorTests {
 				message, latch);
 		this.taskExecutor.execute(task);
 
-		assertTrue(latch.await(10, TimeUnit.SECONDS));
+		assertThat(latch.await(10, TimeUnit.SECONDS)).isTrue();
 
-		assertEquals("Task should have completed within timeout", 0, latch
-				.getCount());
+		assertThat(latch
+				.getCount()).as("Task should have completed within timeout").isEqualTo(0);
 		Message<?> reply = replyChannel.receive(10);
-		assertNull("No message should have been sent normally", reply);
+		assertThat(reply).as("No message should have been sent normally").isNull();
 		this.store.expireMessageGroups(-10000);
 		Message<?> discardedMessage = discardChannel.receive(10000);
-		assertNotNull("A message should have been discarded", discardedMessage);
-		assertEquals(message, discardedMessage);
+		assertThat(discardedMessage).as("A message should have been discarded").isNotNull();
+		assertThat(discardedMessage).isEqualTo(message);
 	}
 
 	@Test
@@ -148,16 +143,15 @@ public class ConcurrentAggregatorTests {
 		this.taskExecutor.execute(task1);
 		this.taskExecutor.execute(task2);
 
-		assertTrue(latch.await(10, TimeUnit.SECONDS));
+		assertThat(latch.await(10, TimeUnit.SECONDS)).isTrue();
 
-		assertEquals("handlers should have been invoked within time limit", 0,
-				latch.getCount());
+		assertThat(latch.getCount()).as("handlers should have been invoked within time limit").isEqualTo(0);
 		this.store.expireMessageGroups(-10000);
 		Message<?> reply = replyChannel.receive(1000);
-		assertNotNull("A reply message should have been received", reply);
-		assertEquals(15, reply.getPayload());
-		assertNull(task1.getException());
-		assertNull(task2.getException());
+		assertThat(reply).as("A reply message should have been received").isNotNull();
+		assertThat(reply.getPayload()).isEqualTo(15);
+		assertThat(task1.getException()).isNull();
+		assertThat(task2.getException()).isNull();
 	}
 
 	@Test
@@ -187,16 +181,16 @@ public class ConcurrentAggregatorTests {
 		this.taskExecutor.execute(new AggregatorTestTask(this.aggregator,
 				message4, latch));
 
-		assertTrue(latch.await(10, TimeUnit.SECONDS));
+		assertThat(latch.await(10, TimeUnit.SECONDS)).isTrue();
 
 		@SuppressWarnings("unchecked")
 		Message<Integer> reply1 = (Message<Integer>) replyChannel1.receive(1000);
-		assertNotNull(reply1);
-		assertThat(reply1.getPayload(), is(105));
+		assertThat(reply1).isNotNull();
+		assertThat(reply1.getPayload()).isEqualTo(105);
 		@SuppressWarnings("unchecked")
 		Message<Integer> reply2 = (Message<Integer>) replyChannel2.receive(1000);
-		assertNotNull(reply2);
-		assertThat(reply2.getPayload(), is(2431));
+		assertThat(reply2).isNotNull();
+		assertThat(reply2.getPayload()).isEqualTo(2431);
 	}
 
 	@Test
@@ -210,17 +204,17 @@ public class ConcurrentAggregatorTests {
 		this.aggregator.setDiscardChannel(discardChannel);
 		this.aggregator.handleMessage(createMessage(1, 1, 1, 1, replyChannel,
 				null));
-		assertEquals(1, replyChannel.receive(1000).getPayload());
+		assertThat(replyChannel.receive(1000).getPayload()).isEqualTo(1);
 		this.aggregator.handleMessage(createMessage(3, 2, 1, 1, replyChannel,
 				null));
-		assertEquals(3, replyChannel.receive(1000).getPayload());
+		assertThat(replyChannel.receive(1000).getPayload()).isEqualTo(3);
 		this.aggregator.handleMessage(createMessage(4, 3, 1, 1, replyChannel,
 				null));
-		assertEquals(4, replyChannel.receive(1000).getPayload());
+		assertThat(replyChannel.receive(1000).getPayload()).isEqualTo(4);
 		// next message with same correlation ID is discarded
 		this.aggregator.handleMessage(createMessage(2, 1, 1, 1, replyChannel,
 				null));
-		assertEquals(2, discardChannel.receive(1000).getPayload());
+		assertThat(discardChannel.receive(1000).getPayload()).isEqualTo(2);
 	}
 
 	@Test
@@ -234,20 +228,20 @@ public class ConcurrentAggregatorTests {
 		this.aggregator.setDiscardChannel(discardChannel);
 		this.aggregator.handleMessage(createMessage(1, 1, 1, 1, replyChannel,
 				null));
-		assertEquals(1, replyChannel.receive(1000).getPayload());
+		assertThat(replyChannel.receive(1000).getPayload()).isEqualTo(1);
 		this.aggregator.handleMessage(createMessage(2, 2, 1, 1, replyChannel,
 				null));
-		assertEquals(2, replyChannel.receive(1000).getPayload());
+		assertThat(replyChannel.receive(1000).getPayload()).isEqualTo(2);
 		this.aggregator.handleMessage(createMessage(3, 3, 1, 1, replyChannel,
 				null));
-		assertEquals(3, replyChannel.receive(1000).getPayload());
+		assertThat(replyChannel.receive(1000).getPayload()).isEqualTo(3);
 		this.aggregator.handleMessage(createMessage(4, 4, 1, 1, replyChannel,
 				null));
-		assertEquals(4, replyChannel.receive(1000).getPayload());
+		assertThat(replyChannel.receive(1000).getPayload()).isEqualTo(4);
 		this.aggregator.handleMessage(createMessage(5, 1, 1, 1, replyChannel,
 				null));
-		assertEquals(5, replyChannel.receive(1000).getPayload());
-		assertNull(discardChannel.receive(0));
+		assertThat(replyChannel.receive(1000).getPayload()).isEqualTo(5);
+		assertThat(discardChannel.receive(0)).isNull();
 	}
 
 	@Test(expected = MessageHandlingException.class)
@@ -277,11 +271,11 @@ public class ConcurrentAggregatorTests {
 		this.taskExecutor.execute(new AggregatorTestTask(this.aggregator,
 				message4, latch));
 
-		assertTrue(latch.await(10, TimeUnit.SECONDS));
+		assertThat(latch.await(10, TimeUnit.SECONDS)).isTrue();
 
 		Message<?> reply = replyChannel.receive(10000);
-		assertNotNull("A message should be aggregated", reply);
-		assertThat(reply.getPayload(), is(105));
+		assertThat(reply).as("A message should be aggregated").isNotNull();
+		assertThat(reply.getPayload()).isEqualTo(105);
 	}
 
 

spring-integration-core/src/test/java/org/springframework/integration/aggregator/CorrelatingMessageBarrierTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2018 the original author or authors.
+ * Copyright 2002-2019 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -16,10 +16,7 @@
 
 package org.springframework.integration.aggregator;
 
-import static org.hamcrest.CoreMatchers.is;
-import static org.hamcrest.Matchers.notNullValue;
-import static org.hamcrest.Matchers.nullValue;
-import static org.junit.Assert.assertThat;
+import static org.assertj.core.api.Assertions.assertThat;
 import static org.mockito.ArgumentMatchers.isA;
 import static org.mockito.Mockito.verify;
 import static org.mockito.Mockito.when;
@@ -69,7 +66,7 @@ public class CorrelatingMessageBarrierTests {
 	public void shouldPassMessage() {
 		Message<Object> message = testMessage();
 		barrier.handleMessage(message);
-		assertThat(barrier.receive(), is(message));
+		assertThat(barrier.receive()).isEqualTo(message);
 	}
 
 	@Test
@@ -78,10 +75,10 @@ public class CorrelatingMessageBarrierTests {
 		Message<Object> message2 = testMessage();
 		barrier.handleMessage(message);
 		verify(correlationStrategy).getCorrelationKey(message);
-		assertThat(barrier.receive(), is(notNullValue()));
+		assertThat(barrier.receive()).isNotNull();
 		barrier.handleMessage(message2);
-		assertThat(barrier.receive(), is(notNullValue()));
-		assertThat(barrier.receive(), is(nullValue()));
+		assertThat(barrier.receive()).isNotNull();
+		assertThat(barrier.receive()).isNull();
 	}
 
 	@Test(timeout = 10000)
@@ -103,10 +100,10 @@ public class CorrelatingMessageBarrierTests {
 			Thread.currentThread().interrupt();
 		}
 
-		assertThat((barrier.receive()), is(notNullValue()));
+		assertThat((barrier.receive())).isNotNull();
 		for (int i = 0; i < 199; i++) {
 			trackingReleaseStrategy.release("foo");
-			assertThat((barrier.receive()), is(notNullValue()));
+			assertThat((barrier.receive())).isNotNull();
 		}
 		exec.shutdownNow();
 	}

spring-integration-core/src/test/java/org/springframework/integration/aggregator/CorrelatingMessageHandlerTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2018 the original author or authors.
+ * Copyright 2002-2019 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -16,9 +16,8 @@
 
 package org.springframework.integration.aggregator;
 
-import static org.junit.Assert.assertEquals;
-import static org.junit.Assert.assertTrue;
-import static org.junit.Assert.fail;
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.assertj.core.api.Assertions.fail;
 import static org.mockito.ArgumentMatchers.any;
 import static org.mockito.ArgumentMatchers.isA;
 import static org.mockito.Mockito.doAnswer;
@@ -118,7 +117,7 @@ public class CorrelatingMessageHandlerTests {
 			fail("Expected MessageHandlingException");
 		}
 		catch (MessageHandlingException e) {
-			assertEquals(0, store.getMessageGroup(correlationKey).size());
+			assertThat(store.getMessageGroup(correlationKey).size()).isEqualTo(0);
 		}
 
 		verify(correlationStrategy).getCorrelationKey(message1);
@@ -154,9 +153,9 @@ public class CorrelatingMessageHandlerTests {
 			bothMessagesHandled.countDown();
 		});
 
-		assertTrue(bothMessagesHandled.await(10, TimeUnit.SECONDS));
+		assertThat(bothMessagesHandled.await(10, TimeUnit.SECONDS)).isTrue();
 
-		assertEquals(0, store.expireMessageGroups(10000));
+		assertThat(store.expireMessageGroups(10000)).isEqualTo(0);
 		exec.shutdownNow();
 	}
 

spring-integration-core/src/test/java/org/springframework/integration/aggregator/CorrelationStrategyAdapterTests.java

@@ -16,7 +16,7 @@
 
 package org.springframework.integration.aggregator;
 
-import static org.junit.Assert.assertEquals;
+import static org.assertj.core.api.Assertions.assertThat;
 import static org.mockito.Mockito.mock;
 
 import org.junit.Before;
@@ -47,7 +47,7 @@ public class CorrelationStrategyAdapterTests {
 		MethodInvokingCorrelationStrategy adapter =
 				new MethodInvokingCorrelationStrategy(new SimpleMessageCorrelator(), "getKey");
 		adapter.setBeanFactory(mock(BeanFactory.class));
-		assertEquals("b", adapter.getCorrelationKey(message));
+		assertThat(adapter.getCorrelationKey(message)).isEqualTo("b");
 	}
 
 	@Test
@@ -56,7 +56,7 @@ public class CorrelationStrategyAdapterTests {
 				new MethodInvokingCorrelationStrategy(new SimpleMessageCorrelator(),
 				ReflectionUtils.findMethod(SimpleMessageCorrelator.class, "getKey", Message.class));
 		adapter.setBeanFactory(mock(BeanFactory.class));
-		assertEquals("b", adapter.getCorrelationKey(message));
+		assertThat(adapter.getCorrelationKey(message)).isEqualTo("b");
 	}
 
 	@Test
@@ -64,7 +64,7 @@ public class CorrelationStrategyAdapterTests {
 		MethodInvokingCorrelationStrategy adapter =
 				new MethodInvokingCorrelationStrategy(new SimplePojoCorrelator(), "getKey");
 		adapter.setBeanFactory(mock(BeanFactory.class));
-		assertEquals("foo", adapter.getCorrelationKey(message));
+		assertThat(adapter.getCorrelationKey(message)).isEqualTo("foo");
 	}
 
 	@Test
@@ -72,7 +72,7 @@ public class CorrelationStrategyAdapterTests {
 		MethodInvokingCorrelationStrategy adapter =
 				new MethodInvokingCorrelationStrategy(new SimpleHeaderCorrelator(), "getKey");
 		adapter.setBeanFactory(mock(BeanFactory.class));
-		assertEquals("b", adapter.getCorrelationKey(message));
+		assertThat(adapter.getCorrelationKey(message)).isEqualTo("b");
 	}
 
 	@Test
@@ -80,7 +80,7 @@ public class CorrelationStrategyAdapterTests {
 		MethodInvokingCorrelationStrategy adapter = new MethodInvokingCorrelationStrategy(new MultiHeaderCorrelator(),
 				ReflectionUtils.findMethod(MultiHeaderCorrelator.class, "getKey", String.class, String.class));
 		adapter.setBeanFactory(mock(BeanFactory.class));
-		assertEquals("bd", adapter.getCorrelationKey(message));
+		assertThat(adapter.getCorrelationKey(message)).isEqualTo("bd");
 	}
 
 	private static class MultiHeaderCorrelator {

spring-integration-core/src/test/java/org/springframework/integration/aggregator/ExpressionEvaluatingCorrelationStrategyTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2016 the original author or authors.
+ * Copyright 2002-2019 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -16,10 +16,7 @@
 
 package org.springframework.integration.aggregator;
 
-import static org.hamcrest.CoreMatchers.instanceOf;
-import static org.hamcrest.CoreMatchers.is;
-import static org.junit.Assert.assertNotNull;
-import static org.junit.Assert.assertThat;
+import static org.assertj.core.api.Assertions.assertThat;
 import static org.mockito.Mockito.mock;
 
 import org.junit.Test;
@@ -65,8 +62,8 @@ public class ExpressionEvaluatingCorrelationStrategyTests {
 		strategy = new ExpressionEvaluatingCorrelationStrategy(expression);
 		strategy.setBeanFactory(mock(BeanFactory.class));
 		Object correlationKey = strategy.getCorrelationKey(new GenericMessage<String>("bla"));
-		assertThat(correlationKey, is(instanceOf(String.class)));
-		assertThat((String) correlationKey, is("b"));
+		assertThat(correlationKey).isInstanceOf(String.class);
+		assertThat((String) correlationKey).isEqualTo("b");
 	}
 
 	@Test
@@ -78,7 +75,7 @@ public class ExpressionEvaluatingCorrelationStrategyTests {
 		Message<?> message = MessageBuilder.withPayload("foo").setSequenceNumber(1).setSequenceSize(1).build();
 		inputChannel.send(message);
 		Message<?> reply = outputChannel.receive(0);
-		assertNotNull(reply);
+		assertThat(reply).isNotNull();
 		context.close();
 	}
 

spring-integration-core/src/test/java/org/springframework/integration/aggregator/ExpressionEvaluatingMessageGroupProcessorTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2018 the original author or authors.
+ * Copyright 2002-2019 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -16,8 +16,7 @@
 
 package org.springframework.integration.aggregator;
 
-import static org.junit.Assert.assertEquals;
-import static org.junit.Assert.assertTrue;
+import static org.assertj.core.api.Assertions.assertThat;
 import static org.mockito.Mockito.mock;
 import static org.mockito.Mockito.when;
 
@@ -69,9 +68,9 @@ public class ExpressionEvaluatingMessageGroupProcessorTests {
 		processor = new ExpressionEvaluatingMessageGroupProcessor("#root.size()");
 		processor.setBeanFactory(mock(BeanFactory.class));
 		Object result = processor.processMessageGroup(group);
-		assertTrue(result instanceof AbstractIntegrationMessageBuilder<?>);
+		assertThat(result instanceof AbstractIntegrationMessageBuilder<?>).isTrue();
 		Message<?> resultMessage = ((AbstractIntegrationMessageBuilder<?>) result).build();
-		assertEquals(5, resultMessage.getPayload());
+		assertThat(resultMessage.getPayload()).isEqualTo(5);
 	}
 
 	@Test
@@ -81,9 +80,9 @@ public class ExpressionEvaluatingMessageGroupProcessorTests {
 		processor.setBeanFactory(mock(BeanFactory.class));
 		Object result = processor.processMessageGroup(group);
 		processor.setBeanFactory(mock(BeanFactory.class));
-		assertTrue(result instanceof AbstractIntegrationMessageBuilder<?>);
+		assertThat(result instanceof AbstractIntegrationMessageBuilder<?>).isTrue();
 		Message<?> resultMessage = ((AbstractIntegrationMessageBuilder<?>) result).build();
-		assertEquals("bar", resultMessage.getHeaders().get("foo"));
+		assertThat(resultMessage.getHeaders().get("foo")).isEqualTo("bar");
 	}
 
 	@Test
@@ -92,16 +91,16 @@ public class ExpressionEvaluatingMessageGroupProcessorTests {
 		processor = new ExpressionEvaluatingMessageGroupProcessor("![payload]");
 		processor.setBeanFactory(mock(BeanFactory.class));
 		Object result = processor.processMessageGroup(group);
-		assertTrue(result instanceof AbstractIntegrationMessageBuilder<?>);
+		assertThat(result instanceof AbstractIntegrationMessageBuilder<?>).isTrue();
 		Message<?> resultMessage = ((AbstractIntegrationMessageBuilder<?>) result).build();
-		assertTrue(resultMessage.getPayload() instanceof Collection<?>);
+		assertThat(resultMessage.getPayload() instanceof Collection<?>).isTrue();
 		Collection<?> list = (Collection<?>) resultMessage.getPayload();
-		assertEquals(5, list.size());
-		assertTrue(list.contains(1));
-		assertTrue(list.contains(2));
-		assertTrue(list.contains(3));
-		assertTrue(list.contains(4));
-		assertTrue(list.contains(5));
+		assertThat(list.size()).isEqualTo(5);
+		assertThat(list.contains(1)).isTrue();
+		assertThat(list.contains(2)).isTrue();
+		assertThat(list.contains(3)).isTrue();
+		assertThat(list.contains(4)).isTrue();
+		assertThat(list.contains(5)).isTrue();
 	}
 
 	@Test
@@ -110,14 +109,14 @@ public class ExpressionEvaluatingMessageGroupProcessorTests {
 		processor = new ExpressionEvaluatingMessageGroupProcessor("?[payload>2].![payload]");
 		processor.setBeanFactory(mock(BeanFactory.class));
 		Object result = processor.processMessageGroup(group);
-		assertTrue(result instanceof AbstractIntegrationMessageBuilder<?>);
+		assertThat(result instanceof AbstractIntegrationMessageBuilder<?>).isTrue();
 		Message<?> resultMessage = ((AbstractIntegrationMessageBuilder<?>) result).build();
-		assertTrue(resultMessage.getPayload() instanceof Collection<?>);
+		assertThat(resultMessage.getPayload() instanceof Collection<?>).isTrue();
 		Collection<?> list = (Collection<?>) resultMessage.getPayload();
-		assertEquals(3, list.size());
-		assertTrue(list.contains(3));
-		assertTrue(list.contains(4));
-		assertTrue(list.contains(5));
+		assertThat(list.size()).isEqualTo(3);
+		assertThat(list.contains(3)).isTrue();
+		assertThat(list.contains(4)).isTrue();
+		assertThat(list.contains(5)).isTrue();
 	}
 
 	@Test
@@ -127,9 +126,9 @@ public class ExpressionEvaluatingMessageGroupProcessorTests {
 				getClass().getName()));
 		processor.setBeanFactory(mock(BeanFactory.class));
 		Object result = processor.processMessageGroup(group);
-		assertTrue(result instanceof AbstractIntegrationMessageBuilder<?>);
+		assertThat(result instanceof AbstractIntegrationMessageBuilder<?>).isTrue();
 		Message<?> resultMessage = ((AbstractIntegrationMessageBuilder<?>) result).build();
-		assertEquals(3 + 4 + 5, resultMessage.getPayload());
+		assertThat(resultMessage.getPayload()).isEqualTo(3 + 4 + 5);
 	}
 
 

spring-integration-core/src/test/java/org/springframework/integration/aggregator/ExpressionEvaluatingReleaseStrategyTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2018 the original author or authors.
+ * Copyright 2002-2019 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -16,8 +16,7 @@
 
 package org.springframework.integration.aggregator;
 
-import static org.hamcrest.CoreMatchers.is;
-import static org.junit.Assert.assertThat;
+import static org.assertj.core.api.Assertions.assertThat;
 import static org.mockito.Mockito.mock;
 
 import org.junit.Before;
@@ -52,21 +51,21 @@ public class ExpressionEvaluatingReleaseStrategyTests {
 	public void testCompletedWithSizeSpelEvaluated() {
 		strategy = new ExpressionEvaluatingReleaseStrategy("#root.size()==5");
 		strategy.setBeanFactory(mock(BeanFactory.class));
-		assertThat(strategy.canRelease(messages), is(true));
+		assertThat(strategy.canRelease(messages)).isTrue();
 	}
 
 	@Test
 	public void testCompletedWithFilterSpelEvaluated() {
 		strategy = new ExpressionEvaluatingReleaseStrategy("!messages.?[payload==5].empty");
 		strategy.setBeanFactory(mock(BeanFactory.class));
-		assertThat(strategy.canRelease(messages), is(true));
+		assertThat(strategy.canRelease(messages)).isTrue();
 	}
 
 	@Test
 	public void testCompletedWithFilterSpelReturnsNotCompleted() {
 		strategy = new ExpressionEvaluatingReleaseStrategy("!messages.?[payload==6].empty");
 		strategy.setBeanFactory(mock(BeanFactory.class));
-		assertThat(strategy.canRelease(messages), is(false));
+		assertThat(strategy.canRelease(messages)).isFalse();
 	}
 
 }

spring-integration-core/src/test/java/org/springframework/integration/aggregator/HeaderAttributeCorrelationStrategyTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2010 the original author or authors.
+ * Copyright 2002-2019 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -16,7 +16,7 @@
 
 package org.springframework.integration.aggregator;
 
-import static org.junit.Assert.assertEquals;
+import static org.assertj.core.api.Assertions.assertThat;
 
 import org.junit.Test;
 
@@ -34,7 +34,7 @@ public class HeaderAttributeCorrelationStrategyTests {
 		String testHeaderName = "header.for.test";
 		Message<?> message = MessageBuilder.withPayload("irrelevantData").setHeader(testHeaderName, testedHeaderValue).build();
 		HeaderAttributeCorrelationStrategy correlationStrategy = new HeaderAttributeCorrelationStrategy(testHeaderName);
-		assertEquals(testedHeaderValue, correlationStrategy.getCorrelationKey(message));
+		assertThat(correlationStrategy.getCorrelationKey(message)).isEqualTo(testedHeaderValue);
 	}
 
 

spring-integration-core/src/test/java/org/springframework/integration/aggregator/MessageSequenceComparatorTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2018 the original author or authors.
+ * Copyright 2002-2019 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -16,7 +16,7 @@
 
 package org.springframework.integration.aggregator;
 
-import static org.junit.Assert.assertEquals;
+import static org.assertj.core.api.Assertions.assertThat;
 
 import java.util.Comparator;
 
@@ -38,7 +38,7 @@ public class MessageSequenceComparatorTests {
 				.setSequenceNumber(1).build();
 		Message<String> message2 = MessageBuilder.withPayload("test2")
 				.setSequenceNumber(2).build();
-		assertEquals(-1, comparator.compare(message1, message2));
+		assertThat(comparator.compare(message1, message2)).isEqualTo(-1);
 	}
 
 	@Test
@@ -48,7 +48,7 @@ public class MessageSequenceComparatorTests {
 				.setSequenceNumber(3).build();
 		Message<String> message2 = MessageBuilder.withPayload("test2")
 				.setSequenceNumber(3).build();
-		assertEquals(0, comparator.compare(message1, message2));
+		assertThat(comparator.compare(message1, message2)).isEqualTo(0);
 	}
 
 	@Test
@@ -58,7 +58,7 @@ public class MessageSequenceComparatorTests {
 				.setSequenceNumber(5).build();
 		Message<String> message2 = MessageBuilder.withPayload("test2")
 				.setSequenceNumber(3).build();
-		assertEquals(1, comparator.compare(message1, message2));
+		assertThat(comparator.compare(message1, message2)).isEqualTo(1);
 	}
 
 	@Test
@@ -66,7 +66,7 @@ public class MessageSequenceComparatorTests {
 		Comparator<Message<?>> comparator = new MessageSequenceComparator();
 		Message<String> message1 = MessageBuilder.withPayload("test1").build();
 		Message<String> message2 = MessageBuilder.withPayload("test2").build();
-		assertEquals(0, comparator.compare(message1, message2));
+		assertThat(comparator.compare(message1, message2)).isEqualTo(0);
 	}
 
 }

spring-integration-core/src/test/java/org/springframework/integration/aggregator/MethodInvokingMessageGroupProcessorTests.java

@@ -16,12 +16,8 @@
 
 package org.springframework.integration.aggregator;
 
-import static org.hamcrest.CoreMatchers.instanceOf;
-import static org.hamcrest.CoreMatchers.is;
-import static org.junit.Assert.assertEquals;
-import static org.junit.Assert.assertThat;
-import static org.junit.Assert.assertTrue;
-import static org.junit.Assert.fail;
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.assertj.core.api.Assertions.fail;
 import static org.mockito.Mockito.mock;
 import static org.mockito.Mockito.when;
 
@@ -108,7 +104,7 @@ public class MethodInvokingMessageGroupProcessorTests {
 		processor.setBeanFactory(mock(BeanFactory.class));
 		when(this.messageGroupMock.getMessages()).thenReturn(this.messagesUpForProcessing);
 		Object result = processor.processMessageGroup(this.messageGroupMock);
-		assertThat(((AbstractIntegrationMessageBuilder<?>) result).build().getPayload(), is(7));
+		assertThat(((AbstractIntegrationMessageBuilder<?>) result).build().getPayload()).isEqualTo(7);
 	}
 
 	@Test
@@ -132,7 +128,7 @@ public class MethodInvokingMessageGroupProcessorTests {
 		processor.setBeanFactory(mock(BeanFactory.class));
 		when(this.messageGroupMock.getMessages()).thenReturn(this.messagesUpForProcessing);
 		Object result = processor.processMessageGroup(this.messageGroupMock);
-		assertThat(((AbstractIntegrationMessageBuilder<?>) result).build().getPayload(), is(7));
+		assertThat(((AbstractIntegrationMessageBuilder<?>) result).build().getPayload()).isEqualTo(7);
 	}
 
 	@Test
@@ -156,7 +152,7 @@ public class MethodInvokingMessageGroupProcessorTests {
 		processor.setBeanFactory(mock(BeanFactory.class));
 		when(this.messageGroupMock.getMessages()).thenReturn(this.messagesUpForProcessing);
 		Object result = processor.processMessageGroup(this.messageGroupMock);
-		assertThat(((AbstractIntegrationMessageBuilder<?>) result).build().getPayload(), is(7));
+		assertThat(((AbstractIntegrationMessageBuilder<?>) result).build().getPayload()).isEqualTo(7);
 	}
 
 	@Test
@@ -184,7 +180,8 @@ public class MethodInvokingMessageGroupProcessorTests {
 		messagesUpForProcessing.add(MessageBuilder.withPayload(3).setHeader("foo", Arrays.asList(101, 102)).build());
 		when(messageGroupMock.getMessages()).thenReturn(messagesUpForProcessing);
 		Object result = processor.processMessageGroup(messageGroupMock);
-		assertThat(((AbstractIntegrationMessageBuilder<?>) result).build().getPayload(), is("[1, 2, 4, 3, 101, 102]"));
+		assertThat(((AbstractIntegrationMessageBuilder<?>) result).build().getPayload())
+				.isEqualTo("[1, 2, 4, 3, 101, 102]");
 	}
 
 	@Test
@@ -217,7 +214,8 @@ public class MethodInvokingMessageGroupProcessorTests {
 						.build());
 		when(this.messageGroupMock.getMessages()).thenReturn(this.messagesUpForProcessing);
 		Object result = processor.processMessageGroup(this.messageGroupMock);
-		assertThat(((AbstractIntegrationMessageBuilder<?>) result).build().getPayload(), is("[1, 2, 4, 3, 101, 102]"));
+		assertThat(((AbstractIntegrationMessageBuilder<?>) result).build().getPayload())
+				.isEqualTo("[1, 2, 4, 3, 101, 102]");
 	}
 
 	@Test
@@ -242,7 +240,7 @@ public class MethodInvokingMessageGroupProcessorTests {
 		processor.setBeanFactory(mock(BeanFactory.class));
 		when(this.messageGroupMock.getMessages()).thenReturn(this.messagesUpForProcessing);
 		Object result = processor.processMessageGroup(this.messageGroupMock);
-		assertThat(((AbstractIntegrationMessageBuilder<?>) result).build().getPayload(), is("[1, 2, 4]"));
+		assertThat(((AbstractIntegrationMessageBuilder<?>) result).build().getPayload()).isEqualTo("[1, 2, 4]");
 	}
 
 	@Test
@@ -266,7 +264,7 @@ public class MethodInvokingMessageGroupProcessorTests {
 		processor.setBeanFactory(mock(BeanFactory.class));
 		when(this.messageGroupMock.getMessages()).thenReturn(this.messagesUpForProcessing);
 		Object result = processor.processMessageGroup(this.messageGroupMock);
-		assertThat(((AbstractIntegrationMessageBuilder<?>) result).build().getPayload(), is(7));
+		assertThat(((AbstractIntegrationMessageBuilder<?>) result).build().getPayload()).isEqualTo(7);
 	}
 
 	@Test
@@ -290,7 +288,7 @@ public class MethodInvokingMessageGroupProcessorTests {
 		processor.setBeanFactory(mock(BeanFactory.class));
 		when(this.messageGroupMock.getMessages()).thenReturn(this.messagesUpForProcessing);
 		Object result = processor.processMessageGroup(this.messageGroupMock);
-		assertThat(((AbstractIntegrationMessageBuilder<?>) result).build().getPayload(), is(7));
+		assertThat(((AbstractIntegrationMessageBuilder<?>) result).build().getPayload()).isEqualTo(7);
 	}
 
 
@@ -325,7 +323,7 @@ public class MethodInvokingMessageGroupProcessorTests {
 		processor.setConversionService(conversionService);
 		when(this.messageGroupMock.getMessages()).thenReturn(this.messagesUpForProcessing);
 		Object result = processor.processMessageGroup(this.messageGroupMock);
-		assertThat(((AbstractIntegrationMessageBuilder<?>) result).build().getPayload(), is(7));
+		assertThat(((AbstractIntegrationMessageBuilder<?>) result).build().getPayload()).isEqualTo(7);
 	}
 
 	@Test
@@ -358,7 +356,7 @@ public class MethodInvokingMessageGroupProcessorTests {
 		processor.setBeanFactory(mock(BeanFactory.class));
 		when(this.messageGroupMock.getMessages()).thenReturn(this.messagesUpForProcessing);
 		Object result = processor.processMessageGroup(this.messageGroupMock);
-		assertThat(((AbstractIntegrationMessageBuilder<?>) result).build().getPayload(), is(7));
+		assertThat(((AbstractIntegrationMessageBuilder<?>) result).build().getPayload()).isEqualTo(7);
 	}
 
 	@Test
@@ -388,7 +386,7 @@ public class MethodInvokingMessageGroupProcessorTests {
 		processor.setBeanFactory(mock(BeanFactory.class));
 		when(this.messageGroupMock.getMessages()).thenReturn(this.messagesUpForProcessing);
 		Object result = processor.processMessageGroup(this.messageGroupMock);
-		assertThat(((AbstractIntegrationMessageBuilder<?>) result).build().getPayload(), instanceOf(Iterator.class));
+		assertThat(((AbstractIntegrationMessageBuilder<?>) result).build().getPayload()).isInstanceOf(Iterator.class);
 	}
 
 	@Test
@@ -419,8 +417,8 @@ public class MethodInvokingMessageGroupProcessorTests {
 		when(this.messageGroupMock.getMessages()).thenReturn(this.messagesUpForProcessing);
 		Object result = processor.processMessageGroup(this.messageGroupMock);
 		Object payload = ((AbstractIntegrationMessageBuilder<?>) result).build().getPayload();
-		assertTrue(payload instanceof Integer);
-		assertEquals(7, payload);
+		assertThat(payload instanceof Integer).isTrue();
+		assertThat(payload).isEqualTo(7);
 
 	}
 
@@ -447,7 +445,7 @@ public class MethodInvokingMessageGroupProcessorTests {
 		SimpleMessageGroup group = new SimpleMessageGroup("FOO");
 		group.add(new GenericMessage<>("foo"));
 		group.add(new GenericMessage<>("bar"));
-		assertEquals("foo", aggregator.aggregatePayloads(group, null));
+		assertThat(aggregator.aggregatePayloads(group, null)).isEqualTo("foo");
 	}
 
 	@Test
@@ -468,7 +466,7 @@ public class MethodInvokingMessageGroupProcessorTests {
 		SimpleMessageGroup group = new SimpleMessageGroup("FOO");
 		group.add(MessageBuilder.withPayload("foo").setHeader("foo", "bar").build());
 		group.add(MessageBuilder.withPayload("bar").setHeader("foo", "bar").build());
-		assertEquals("foobar", processor.aggregatePayloads(group, processor.aggregateHeaders(group)));
+		assertThat(processor.aggregatePayloads(group, processor.aggregateHeaders(group))).isEqualTo("foobar");
 	}
 
 	@Test
@@ -489,7 +487,7 @@ public class MethodInvokingMessageGroupProcessorTests {
 		SimpleMessageGroup group = new SimpleMessageGroup("FOO");
 		group.add(MessageBuilder.withPayload("foo").setHeader("foo", "bar").build());
 		group.add(MessageBuilder.withPayload("bar").setHeader("foo", "bar").build());
-		assertEquals("foobar", aggregator.aggregatePayloads(group, aggregator.aggregateHeaders(group)));
+		assertThat(aggregator.aggregatePayloads(group, aggregator.aggregateHeaders(group))).isEqualTo("foobar");
 	}
 
 	@Test(expected = IllegalArgumentException.class)
@@ -535,7 +533,7 @@ public class MethodInvokingMessageGroupProcessorTests {
 		SimpleMessageGroup group = new SimpleMessageGroup("FOO");
 		group.add(new GenericMessage<>("foo"));
 		group.add(new GenericMessage<>("bar"));
-		assertEquals("foo", aggregator.aggregatePayloads(group, null));
+		assertThat(aggregator.aggregatePayloads(group, null)).isEqualTo("foo");
 	}
 
 	@Test(expected = IllegalArgumentException.class)
@@ -593,7 +591,7 @@ public class MethodInvokingMessageGroupProcessorTests {
 
 		Message<?> message = MessageBuilder.withPayload("proxy").setCorrelationId("abc").build();
 		input.send(message);
-		assertEquals("hello proxy", output.receive(0).getPayload());
+		assertThat(output.receive(0).getPayload()).isEqualTo("hello proxy");
 	}
 
 	@Test
@@ -615,7 +613,7 @@ public class MethodInvokingMessageGroupProcessorTests {
 
 		Message<?> message = MessageBuilder.withPayload("proxy").setCorrelationId("abc").build();
 		input.send(message);
-		assertEquals("hello proxy", output.receive(0).getPayload());
+		assertThat(output.receive(0).getPayload()).isEqualTo("hello proxy");
 	}
 
 

spring-integration-core/src/test/java/org/springframework/integration/aggregator/MethodInvokingReleaseStrategyTests.java

@@ -16,8 +16,7 @@
 
 package org.springframework.integration.aggregator;
 
-import static org.junit.Assert.assertFalse;
-import static org.junit.Assert.assertTrue;
+import static org.assertj.core.api.Assertions.assertThat;
 import static org.mockito.Mockito.mock;
 
 import java.util.ArrayList;
@@ -47,7 +46,7 @@ public class MethodInvokingReleaseStrategyTests {
 		MethodInvokingReleaseStrategy adapter = new MethodInvokingReleaseStrategy(new AlwaysTrueReleaseStrategy(),
 				"checkCompleteness");
 		adapter.setBeanFactory(mock(BeanFactory.class));
-		assertTrue(adapter.canRelease(createListOfMessages(0)));
+		assertThat(adapter.canRelease(createListOfMessages(0))).isTrue();
 	}
 
 	@Test
@@ -55,7 +54,7 @@ public class MethodInvokingReleaseStrategyTests {
 		MethodInvokingReleaseStrategy adapter = new MethodInvokingReleaseStrategy(new AlwaysFalseReleaseStrategy(),
 				"checkCompleteness");
 		adapter.setBeanFactory(mock(BeanFactory.class));
-		assertFalse(adapter.canRelease(createListOfMessages(0)));
+		assertThat(adapter.canRelease(createListOfMessages(0))).isFalse();
 	}
 
 	@Test
@@ -64,7 +63,7 @@ public class MethodInvokingReleaseStrategyTests {
 
 			@SuppressWarnings("unused")
 			public boolean checkCompletenessOnNonParameterizedListOfMessages(List<Message<?>> messages) {
-				assertTrue(messages.size() > 0);
+				assertThat(messages.size() > 0).isTrue();
 				return messages.size() >
 						new IntegrationMessageHeaderAccessor(messages.iterator().next()).getSequenceSize();
 			}
@@ -74,7 +73,7 @@ public class MethodInvokingReleaseStrategyTests {
 				"checkCompletenessOnNonParameterizedListOfMessages");
 		adapter.setBeanFactory(mock(BeanFactory.class));
 		MessageGroup messages = createListOfMessages(3);
-		assertTrue(adapter.canRelease(messages));
+		assertThat(adapter.canRelease(messages)).isTrue();
 	}
 
 	@Test
@@ -83,7 +82,7 @@ public class MethodInvokingReleaseStrategyTests {
 
 			@SuppressWarnings("unused")
 			public boolean checkCompletenessOnListOfMessagesParametrizedWithWildcard(List<Message<?>> messages) {
-				assertTrue(messages.size() > 0);
+				assertThat(messages.size() > 0).isTrue();
 				return messages.size() >
 						new IntegrationMessageHeaderAccessor(messages.iterator().next()).getSequenceSize();
 			}
@@ -93,7 +92,7 @@ public class MethodInvokingReleaseStrategyTests {
 				"checkCompletenessOnListOfMessagesParametrizedWithWildcard");
 		adapter.setBeanFactory(mock(BeanFactory.class));
 		MessageGroup messages = createListOfMessages(3);
-		assertTrue(adapter.canRelease(messages));
+		assertThat(adapter.canRelease(messages)).isTrue();
 	}
 
 	@Test
@@ -102,7 +101,7 @@ public class MethodInvokingReleaseStrategyTests {
 
 			@SuppressWarnings("unused")
 			public boolean checkCompletenessOnListOfMessagesParametrizedWithString(List<Message<String>> messages) {
-				assertTrue(messages.size() > 0);
+				assertThat(messages.size() > 0).isTrue();
 				return messages.size() > new IntegrationMessageHeaderAccessor(messages.iterator().next())
 						.getSequenceSize();
 			}
@@ -112,7 +111,7 @@ public class MethodInvokingReleaseStrategyTests {
 				"checkCompletenessOnListOfMessagesParametrizedWithString");
 		adapter.setBeanFactory(mock(BeanFactory.class));
 		MessageGroup messages = createListOfMessages(3);
-		assertTrue(adapter.canRelease(messages));
+		assertThat(adapter.canRelease(messages)).isTrue();
 	}
 
 	@Test
@@ -135,7 +134,7 @@ public class MethodInvokingReleaseStrategyTests {
 				"checkCompletenessOnListOfStrings");
 		adapter.setBeanFactory(mock(BeanFactory.class));
 		MessageGroup messages = createListOfMessages(3);
-		assertTrue(adapter.canRelease(messages));
+		assertThat(adapter.canRelease(messages)).isTrue();
 	}
 
 	@Test
@@ -158,7 +157,7 @@ public class MethodInvokingReleaseStrategyTests {
 				"checkCompletenessOnListOfStrings");
 		adapter.setBeanFactory(mock(BeanFactory.class));
 		MessageGroup messages = createListOfMessages(3);
-		assertTrue(adapter.canRelease(messages));
+		assertThat(adapter.canRelease(messages)).isTrue();
 	}
 
 	@Test(expected = IllegalStateException.class)
@@ -183,7 +182,7 @@ public class MethodInvokingReleaseStrategyTests {
 				new MethodInvokingReleaseStrategy(new TestReleaseStrategy(), "invalidParameterType");
 		adapter.setBeanFactory(mock(BeanFactory.class));
 		MessageGroup messages = createListOfMessages(3);
-		assertTrue(adapter.canRelease(messages));
+		assertThat(adapter.canRelease(messages)).isTrue();
 	}
 
 	@Test(expected = IllegalStateException.class)
@@ -240,7 +239,7 @@ public class MethodInvokingReleaseStrategyTests {
 				"listSubclassParameter");
 		adapter.setBeanFactory(mock(BeanFactory.class));
 		MessageGroup messages = createListOfMessages(3);
-		assertTrue(adapter.canRelease(messages));
+		assertThat(adapter.canRelease(messages)).isTrue();
 	}
 
 	@Test(expected = ConversionFailedException.class)
@@ -257,7 +256,7 @@ public class MethodInvokingReleaseStrategyTests {
 				new MethodInvokingReleaseStrategy(new TestReleaseStrategy(), "wrongReturnType");
 		adapter.setBeanFactory(mock(BeanFactory.class));
 		MessageGroup messages = createListOfMessages(3);
-		assertTrue(adapter.canRelease(messages));
+		assertThat(adapter.canRelease(messages)).isTrue();
 	}
 
 	@Test(expected = IllegalArgumentException.class)
@@ -288,7 +287,7 @@ public class MethodInvokingReleaseStrategyTests {
 				TestReleaseStrategy.class.getMethod("listSubclassParameter", LinkedList.class));
 		adapter.setBeanFactory(mock(BeanFactory.class));
 		MessageGroup messages = createListOfMessages(3);
-		assertTrue(adapter.canRelease(messages));
+		assertThat(adapter.canRelease(messages)).isTrue();
 	}
 
 	@Test(expected = IllegalStateException.class)

spring-integration-core/src/test/java/org/springframework/integration/aggregator/ResequencerTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2017 the original author or authors.
+ * Copyright 2002-2019 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -16,13 +16,8 @@
 
 package org.springframework.integration.aggregator;
 
-import static org.hamcrest.Matchers.containsString;
-import static org.hamcrest.Matchers.is;
-import static org.junit.Assert.assertEquals;
-import static org.junit.Assert.assertNotNull;
-import static org.junit.Assert.assertNull;
-import static org.junit.Assert.assertThat;
-import static org.junit.Assert.fail;
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.assertj.core.api.Assertions.fail;
 import static org.mockito.Mockito.mock;
 
 import java.util.ArrayList;
@@ -80,12 +75,12 @@ public class ResequencerTests {
 		Message<?> reply1 = replyChannel.receive(0);
 		Message<?> reply2 = replyChannel.receive(0);
 		Message<?> reply3 = replyChannel.receive(0);
-		assertNotNull(reply1);
-		assertThat(new IntegrationMessageHeaderAccessor(reply1).getSequenceNumber(), is(1));
-		assertNotNull(reply2);
-		assertThat(new IntegrationMessageHeaderAccessor(reply2).getSequenceNumber(), is(2));
-		assertNotNull(reply3);
-		assertThat(new IntegrationMessageHeaderAccessor(reply3).getSequenceNumber(), is(3));
+		assertThat(reply1).isNotNull();
+		assertThat(new IntegrationMessageHeaderAccessor(reply1).getSequenceNumber()).isEqualTo(1);
+		assertThat(reply2).isNotNull();
+		assertThat(new IntegrationMessageHeaderAccessor(reply2).getSequenceNumber()).isEqualTo(2);
+		assertThat(reply3).isNotNull();
+		assertThat(new IntegrationMessageHeaderAccessor(reply3).getSequenceNumber()).isEqualTo(3);
 	}
 
 	@Test
@@ -101,10 +96,10 @@ public class ResequencerTests {
 		Message<?> message3 = createMessage("789", "ABC", 3, 3, replyChannel);
 
 		this.resequencer.handleMessage(message3);
-		assertNull(replyChannel.receive(0));
+		assertThat(replyChannel.receive(0)).isNull();
 		this.resequencer.handleMessage(message1);
-		assertNotNull(replyChannel.receive(0));
-		assertNull(replyChannel.receive(0));
+		assertThat(replyChannel.receive(0)).isNotNull();
+		assertThat(replyChannel.receive(0)).isNull();
 	}
 
 	@Test
@@ -125,20 +120,20 @@ public class ResequencerTests {
 		Message<?> message5 = MessageBuilder.withPayload("5").setSequenceNumber(5).setReplyChannel(replyChannel).build();
 
 		this.resequencer.handleMessage(message3);
-		assertNull(replyChannel.receive(0));
+		assertThat(replyChannel.receive(0)).isNull();
 		this.resequencer.handleMessage(message1);
-		assertNotNull(replyChannel.receive(0));
+		assertThat(replyChannel.receive(0)).isNotNull();
 
 		this.resequencer.handleMessage(message2);
 
-		assertNotNull(replyChannel.receive(0));
-		assertNotNull(replyChannel.receive(0));
-		assertNull(replyChannel.receive(0));
+		assertThat(replyChannel.receive(0)).isNotNull();
+		assertThat(replyChannel.receive(0)).isNotNull();
+		assertThat(replyChannel.receive(0)).isNull();
 
 		this.resequencer.handleMessage(message5);
-		assertNull(replyChannel.receive(0));
+		assertThat(replyChannel.receive(0)).isNull();
 		this.resequencer.handleMessage(message4);
-		assertNotNull(replyChannel.receive(0));
+		assertThat(replyChannel.receive(0)).isNotNull();
 	}
 
 	@Test
@@ -154,12 +149,12 @@ public class ResequencerTests {
 		Message<?> reply1 = replyChannel.receive(0);
 		Message<?> reply2 = replyChannel.receive(0);
 		Message<?> reply3 = replyChannel.receive(0);
-		assertNotNull(reply1);
-		assertEquals(1, new IntegrationMessageHeaderAccessor(reply1).getSequenceNumber());
-		assertNotNull(reply2);
-		assertEquals(2, new IntegrationMessageHeaderAccessor(reply2).getSequenceNumber());
-		assertNotNull(reply3);
-		assertEquals(3, new IntegrationMessageHeaderAccessor(reply3).getSequenceNumber());
+		assertThat(reply1).isNotNull();
+		assertThat(new IntegrationMessageHeaderAccessor(reply1).getSequenceNumber()).isEqualTo(1);
+		assertThat(reply2).isNotNull();
+		assertThat(new IntegrationMessageHeaderAccessor(reply2).getSequenceNumber()).isEqualTo(2);
+		assertThat(reply3).isNotNull();
+		assertThat(new IntegrationMessageHeaderAccessor(reply3).getSequenceNumber()).isEqualTo(3);
 	}
 
 	@Test
@@ -179,19 +174,19 @@ public class ResequencerTests {
 		Message<?> reply2 = replyChannel.receive(0);
 		Message<?> reply3 = replyChannel.receive(0);
 		// only messages 1 and 2 should have been received by now
-		assertNotNull(reply1);
-		assertEquals(1, new IntegrationMessageHeaderAccessor(reply1).getSequenceNumber());
-		assertNotNull(reply2);
-		assertEquals(2, new IntegrationMessageHeaderAccessor(reply2).getSequenceNumber());
-		assertNull(reply3);
+		assertThat(reply1).isNotNull();
+		assertThat(new IntegrationMessageHeaderAccessor(reply1).getSequenceNumber()).isEqualTo(1);
+		assertThat(reply2).isNotNull();
+		assertThat(new IntegrationMessageHeaderAccessor(reply2).getSequenceNumber()).isEqualTo(2);
+		assertThat(reply3).isNull();
 		// when sending the last message, the whole sequence must have been sent
 		this.resequencer.handleMessage(message4);
 		reply3 = replyChannel.receive(0);
 		Message<?> reply4 = replyChannel.receive(0);
-		assertNotNull(reply3);
-		assertEquals(3, new IntegrationMessageHeaderAccessor(reply3).getSequenceNumber());
-		assertNotNull(reply4);
-		assertEquals(4, new IntegrationMessageHeaderAccessor(reply4).getSequenceNumber());
+		assertThat(reply3).isNotNull();
+		assertThat(new IntegrationMessageHeaderAccessor(reply3).getSequenceNumber()).isEqualTo(3);
+		assertThat(reply4).isNotNull();
+		assertThat(new IntegrationMessageHeaderAccessor(reply4).getSequenceNumber()).isEqualTo(4);
 	}
 
 	@Test
@@ -210,7 +205,7 @@ public class ResequencerTests {
 			fail("Expected exception");
 		}
 		catch (MessagingException e) {
-			assertThat(e.getMessage(), containsString("out of capacity (2) for group 'ABC'"));
+			assertThat(e.getMessage()).contains("out of capacity (2) for group 'ABC'");
 		}
 	}
 
@@ -229,19 +224,19 @@ public class ResequencerTests {
 		Message<?> reply2 = replyChannel.receive(0);
 		Message<?> reply3 = replyChannel.receive(0);
 		// only messages 1 and 2 should have been received by now
-		assertNotNull(reply1);
-		assertEquals(1, new IntegrationMessageHeaderAccessor(reply1).getSequenceNumber());
-		assertNotNull(reply2);
-		assertEquals(2, new IntegrationMessageHeaderAccessor(reply2).getSequenceNumber());
-		assertNull(reply3);
+		assertThat(reply1).isNotNull();
+		assertThat(new IntegrationMessageHeaderAccessor(reply1).getSequenceNumber()).isEqualTo(1);
+		assertThat(reply2).isNotNull();
+		assertThat(new IntegrationMessageHeaderAccessor(reply2).getSequenceNumber()).isEqualTo(2);
+		assertThat(reply3).isNull();
 		// when sending the last message, the whole sequence must have been sent
 		this.resequencer.handleMessage(message4);
 		reply3 = replyChannel.receive(0);
 		Message<?> reply4 = replyChannel.receive(0);
-		assertNotNull(reply3);
-		assertEquals(3, new IntegrationMessageHeaderAccessor(reply3).getSequenceNumber());
-		assertNotNull(reply4);
-		assertEquals(4, new IntegrationMessageHeaderAccessor(reply4).getSequenceNumber());
+		assertThat(reply3).isNotNull();
+		assertThat(new IntegrationMessageHeaderAccessor(reply3).getSequenceNumber()).isEqualTo(3);
+		assertThat(reply4).isNotNull();
+		assertThat(new IntegrationMessageHeaderAccessor(reply4).getSequenceNumber()).isEqualTo(4);
 	}
 
 	@Test
@@ -254,23 +249,23 @@ public class ResequencerTests {
 		this.resequencer.setDiscardChannel(discardChannel);
 		this.resequencer.handleMessage(message1);
 		this.resequencer.handleMessage(message2);
-		assertEquals(1, store.expireMessageGroups(-10000));
+		assertThat(store.expireMessageGroups(-10000)).isEqualTo(1);
 		Message<?> reply1 = discardChannel.receive(0);
 		Message<?> reply2 = discardChannel.receive(0);
 		Message<?> reply3 = discardChannel.receive(0);
 		// only messages 1 and 2 should have been received by now
-		assertNotNull(reply1);
-		assertNotNull(reply2);
-		assertNull(reply3);
+		assertThat(reply1).isNotNull();
+		assertThat(reply2).isNotNull();
+		assertThat(reply3).isNull();
 		ArrayList<Integer> sequence = new ArrayList<>(
 				Arrays.asList(new IntegrationMessageHeaderAccessor(reply1).getSequenceNumber(),
 						new IntegrationMessageHeaderAccessor(reply2).getSequenceNumber()));
 		Collections.sort(sequence);
-		assertEquals("[1, 2]", sequence.toString());
+		assertThat(sequence.toString()).isEqualTo("[1, 2]");
 		// Once a group is expired, late messages are discarded immediately by default
 		this.resequencer.handleMessage(message3);
 		reply3 = discardChannel.receive(0);
-		assertNotNull(reply3);
+		assertThat(reply3).isNotNull();
 	}
 
 	@Test
@@ -287,9 +282,9 @@ public class ResequencerTests {
 		Message<?> discard1 = discardChannel.receive(0);
 		Message<?> discard2 = discardChannel.receive(0);
 		// message2 has been discarded because it came in with the wrong sequence size
-		assertNotNull(discard1);
-		assertEquals(1, new IntegrationMessageHeaderAccessor(discard1).getSequenceNumber());
-		assertNull(discard2);
+		assertThat(discard1).isNotNull();
+		assertThat(new IntegrationMessageHeaderAccessor(discard1).getSequenceNumber()).isEqualTo(1);
+		assertThat(discard2).isNull();
 	}
 
 	@Test
@@ -302,7 +297,7 @@ public class ResequencerTests {
 		// this.resequencer.discardBarrier(this.resequencer.barriers.get("ABC"));
 		Message<?> reply1 = discardChannel.receive(0);
 		// No message has been received - the message has been rejected.
-		assertNull(reply1);
+		assertThat(reply1).isNull();
 	}
 
 	@Test
@@ -319,23 +314,23 @@ public class ResequencerTests {
 		Message<?> reply2 = replyChannel.receive(0);
 		Message<?> reply3 = replyChannel.receive(0);
 		// no messages should have been received yet
-		assertNull(reply1);
-		assertNull(reply2);
-		assertNull(reply3);
+		assertThat(reply1).isNull();
+		assertThat(reply2).isNull();
+		assertThat(reply3).isNull();
 		// after sending the last message, the whole sequence should have been sent
 		this.resequencer.handleMessage(message4);
 		reply1 = replyChannel.receive(0);
 		reply2 = replyChannel.receive(0);
 		reply3 = replyChannel.receive(0);
 		Message<?> reply4 = replyChannel.receive(0);
-		assertNotNull(reply1);
-		assertEquals(1, new IntegrationMessageHeaderAccessor(reply1).getSequenceNumber());
-		assertNotNull(reply2);
-		assertEquals(2, new IntegrationMessageHeaderAccessor(reply2).getSequenceNumber());
-		assertNotNull(reply3);
-		assertEquals(3, new IntegrationMessageHeaderAccessor(reply3).getSequenceNumber());
-		assertNotNull(reply4);
-		assertEquals(4, new IntegrationMessageHeaderAccessor(reply4).getSequenceNumber());
+		assertThat(reply1).isNotNull();
+		assertThat(new IntegrationMessageHeaderAccessor(reply1).getSequenceNumber()).isEqualTo(1);
+		assertThat(reply2).isNotNull();
+		assertThat(new IntegrationMessageHeaderAccessor(reply2).getSequenceNumber()).isEqualTo(2);
+		assertThat(reply3).isNotNull();
+		assertThat(new IntegrationMessageHeaderAccessor(reply3).getSequenceNumber()).isEqualTo(3);
+		assertThat(reply4).isNotNull();
+		assertThat(new IntegrationMessageHeaderAccessor(reply4).getSequenceNumber()).isEqualTo(4);
 	}
 
 	@Test
@@ -344,7 +339,7 @@ public class ResequencerTests {
 		String correlationId = "ABC";
 		Message<?> message1 = createMessage("123", correlationId, 1, 1, replyChannel);
 		resequencer.handleMessage(message1);
-		assertEquals(0, store.getMessageGroup(correlationId).size());
+		assertThat(store.getMessageGroup(correlationId).size()).isEqualTo(0);
 	}
 
 	@Test
@@ -363,15 +358,15 @@ public class ResequencerTests {
 		this.resequencer.handleMessage(message3);
 		this.resequencer.handleMessage(message2);
 		Message<?> out1 = replyChannel.receive(10);
-		assertNull(out1);
+		assertThat(out1).isNull();
 		out1 = discardChannel.receive(10000);
-		assertNotNull(out1);
+		assertThat(out1).isNotNull();
 		Message<?> out2 = discardChannel.receive(10);
-		assertNotNull(out2);
+		assertThat(out2).isNotNull();
 		Message<?> message1 = createMessage("123", "ABC", 3, 1, null);
 		this.resequencer.handleMessage(message1);
 		Message<?> out3 = discardChannel.receive(0);
-		assertNotNull(out3);
+		assertThat(out3).isNotNull();
 	}
 
 	@Test
@@ -391,17 +386,17 @@ public class ResequencerTests {
 		this.resequencer.handleMessage(message3);
 		this.resequencer.handleMessage(message2);
 		Message<?> out1 = replyChannel.receive(0);
-		assertNull(out1);
+		assertThat(out1).isNull();
 		out1 = discardChannel.receive(10_000);
-		assertNotNull(out1);
+		assertThat(out1).isNotNull();
 		Message<?> out2 = discardChannel.receive(10_000);
-		assertNotNull(out2);
+		assertThat(out2).isNotNull();
 		Message<?> message1 = createMessage("123", "ABC", 3, 1, null);
 		this.resequencer.handleMessage(message1);
 		Message<?> out3 = discardChannel.receive(0);
-		assertNull(out3);
+		assertThat(out3).isNull();
 		out3 = discardChannel.receive(10_000);
-		assertNotNull(out3);
+		assertThat(out3).isNotNull();
 	}
 
 	private static Message<?> createMessage(String payload, Object correlationId, int sequenceSize, int sequenceNumber,

spring-integration-core/src/test/java/org/springframework/integration/aggregator/ResequencingMessageGroupProcessorTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2016 the original author or authors.
+ * Copyright 2002-2019 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -16,9 +16,7 @@
 
 package org.springframework.integration.aggregator;
 
-import static org.hamcrest.Matchers.hasItems;
-import static org.hamcrest.Matchers.is;
-import static org.junit.Assert.assertThat;
+import static org.assertj.core.api.Assertions.assertThat;
 
 import java.util.ArrayList;
 import java.util.List;
@@ -50,7 +48,7 @@ public class ResequencingMessageGroupProcessorTests {
 		messages.add(message3);
 		SimpleMessageGroup group = new SimpleMessageGroup(messages, "x");
 		List<Message> processedMessages = (List<Message>) processor.processMessageGroup(group);
-		assertThat(processedMessages, hasItems(message1, message2, message3));
+		assertThat(processedMessages).contains(message1, message2, message3);
 	}
 
 	@SuppressWarnings({ "rawtypes", "unchecked" })
@@ -66,8 +64,8 @@ public class ResequencingMessageGroupProcessorTests {
 		messages.add(message3);
 		SimpleMessageGroup group = new SimpleMessageGroup(messages, "x");
 		List<Message> processedMessages = (List<Message>) processor.processMessageGroup(group);
-		assertThat(processedMessages, hasItems(message1));
-		assertThat(processedMessages.size(), is(1));
+		assertThat(processedMessages).contains(message1);
+		assertThat(processedMessages.size()).isEqualTo(1);
 	}
 
 }

spring-integration-core/src/test/java/org/springframework/integration/aggregator/SequenceSizeReleaseStrategyTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2018 the original author or authors.
+ * Copyright 2002-2019 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -16,8 +16,7 @@
 
 package org.springframework.integration.aggregator;
 
-import static org.junit.Assert.assertFalse;
-import static org.junit.Assert.assertTrue;
+import static org.assertj.core.api.Assertions.assertThat;
 
 import org.junit.Test;
 
@@ -39,7 +38,7 @@ public class SequenceSizeReleaseStrategyTests {
 		SimpleMessageGroup messages = new SimpleMessageGroup("FOO");
 		messages.add(message);
 		SequenceSizeReleaseStrategy releaseStrategy = new SequenceSizeReleaseStrategy();
-		assertFalse(releaseStrategy.canRelease(messages));
+		assertThat(releaseStrategy.canRelease(messages)).isFalse();
 	}
 
 	@Test
@@ -50,13 +49,13 @@ public class SequenceSizeReleaseStrategyTests {
 		messages.add(message1);
 		messages.add(message2);
 		SequenceSizeReleaseStrategy releaseStrategy = new SequenceSizeReleaseStrategy();
-		assertTrue(releaseStrategy.canRelease(messages));
+		assertThat(releaseStrategy.canRelease(messages)).isTrue();
 	}
 
 	@Test
 	public void testEmptyList() {
 		SequenceSizeReleaseStrategy releaseStrategy = new SequenceSizeReleaseStrategy();
-		assertTrue(releaseStrategy.canRelease(new SimpleMessageGroup("FOO")));
+		assertThat(releaseStrategy.canRelease(new SimpleMessageGroup("FOO"))).isTrue();
 	}
 
 	@Test
@@ -67,7 +66,7 @@ public class SequenceSizeReleaseStrategyTests {
 		Message<String> message = MessageBuilder.withPayload("test1").setSequenceSize(1).build();
 		messages.add(message);
 		messages.remove(message);
-		assertTrue(releaseStrategy.canRelease(messages));
+		assertThat(releaseStrategy.canRelease(messages)).isTrue();
 	}
 
 	@Test
@@ -77,7 +76,7 @@ public class SequenceSizeReleaseStrategyTests {
 
 		SimpleMessageGroup messages = new SimpleMessageGroup("FOO");
 
-		assertTrue(releaseStrategy.canRelease(groupWithFirstMessagesOfIncompleteSequence(messages)));
+		assertThat(releaseStrategy.canRelease(groupWithFirstMessagesOfIncompleteSequence(messages))).isTrue();
 	}
 
 	private SimpleMessageGroup groupWithFirstMessagesOfIncompleteSequence(SimpleMessageGroup messages) {
@@ -96,7 +95,7 @@ public class SequenceSizeReleaseStrategyTests {
 
 		boolean canRelease = releaseStrategy.canRelease(groupWithLastAndFirstMessagesOfIncompleteSequence());
 
-		assertTrue(canRelease);
+		assertThat(canRelease).isTrue();
 	}
 
 	private MessageGroup groupWithLastAndFirstMessagesOfIncompleteSequence() {
@@ -124,15 +123,15 @@ public class SequenceSizeReleaseStrategyTests {
 		Message<String> message5 = MessageBuilder.withPayload("test5").setSequenceSize(5).setSequenceNumber(5).build();
 
 		messages.add(message5);
-		assertFalse(releaseStrategy.canRelease(messages));
+		assertThat(releaseStrategy.canRelease(messages)).isFalse();
 		messages.add(message1);
-		assertTrue(releaseStrategy.canRelease(messages));
+		assertThat(releaseStrategy.canRelease(messages)).isTrue();
 		messages.add(message2);
-		assertTrue(releaseStrategy.canRelease(messages));
+		assertThat(releaseStrategy.canRelease(messages)).isTrue();
 		messages.add(message3);
-		assertTrue(releaseStrategy.canRelease(messages));
+		assertThat(releaseStrategy.canRelease(messages)).isTrue();
 		messages.add(message4);
-		assertTrue(releaseStrategy.canRelease(messages));
+		assertThat(releaseStrategy.canRelease(messages)).isTrue();
 	}
 
 }

spring-integration-core/src/test/java/org/springframework/integration/aggregator/TimeoutCountSequenceSizeReleaseStrategyTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2018 the original author or authors.
+ * Copyright 2002-2019 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -16,8 +16,7 @@
 
 package org.springframework.integration.aggregator;
 
-import static org.junit.Assert.assertFalse;
-import static org.junit.Assert.assertTrue;
+import static org.assertj.core.api.Assertions.assertThat;
 
 import org.junit.Test;
 
@@ -38,7 +37,7 @@ public class TimeoutCountSequenceSizeReleaseStrategyTests {
 		SimpleMessageGroup messages = new SimpleMessageGroup("FOO");
 		messages.add(message);
 		TimeoutCountSequenceSizeReleaseStrategy releaseStrategy = new TimeoutCountSequenceSizeReleaseStrategy();
-		assertFalse(releaseStrategy.canRelease(messages));
+		assertThat(releaseStrategy.canRelease(messages)).isFalse();
 	}
 
 	@Test
@@ -50,7 +49,7 @@ public class TimeoutCountSequenceSizeReleaseStrategyTests {
 		TimeoutCountSequenceSizeReleaseStrategy releaseStrategy =
 				new TimeoutCountSequenceSizeReleaseStrategy(TimeoutCountSequenceSizeReleaseStrategy.DEFAULT_THRESHOLD,
 						-100);
-		assertTrue(releaseStrategy.canRelease(messages));
+		assertThat(releaseStrategy.canRelease(messages)).isTrue();
 	}
 
 	@Test
@@ -62,7 +61,7 @@ public class TimeoutCountSequenceSizeReleaseStrategyTests {
 		TimeoutCountSequenceSizeReleaseStrategy releaseStrategy =
 				new TimeoutCountSequenceSizeReleaseStrategy(1,
 						TimeoutCountSequenceSizeReleaseStrategy.DEFAULT_TIMEOUT);
-		assertTrue(releaseStrategy.canRelease(messages));
+		assertThat(releaseStrategy.canRelease(messages)).isTrue();
 	}
 
 	@Test
@@ -75,13 +74,13 @@ public class TimeoutCountSequenceSizeReleaseStrategyTests {
 		messages.add(message1);
 		messages.add(message2);
 		SequenceSizeReleaseStrategy releaseStrategy = new SequenceSizeReleaseStrategy();
-		assertTrue(releaseStrategy.canRelease(messages));
+		assertThat(releaseStrategy.canRelease(messages)).isTrue();
 	}
 
 	@Test
 	public void testEmptyList() {
 		SequenceSizeReleaseStrategy releaseStrategy = new SequenceSizeReleaseStrategy();
-		assertTrue(releaseStrategy.canRelease(new SimpleMessageGroup("FOO")));
+		assertThat(releaseStrategy.canRelease(new SimpleMessageGroup("FOO"))).isTrue();
 	}
 
 }

spring-integration-core/src/test/java/org/springframework/integration/aggregator/integration/AggregatorExpressionIntegrationTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2018 the original author or authors.
+ * Copyright 2002-2019 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -16,7 +16,7 @@
 
 package org.springframework.integration.aggregator.integration;
 
-import static org.junit.Assert.assertEquals;
+import static org.assertj.core.api.Assertions.assertThat;
 
 import java.util.HashMap;
 import java.util.Map;
@@ -57,7 +57,7 @@ public class AggregatorExpressionIntegrationTests {
 			Map<String, Object> headers = stubHeaders(i, 5, 1);
 			this.input.send(new GenericMessage<>(i, headers));
 		}
-		assertEquals("[0, 1, 2, 3, 4]", this.output.receive().getPayload());
+		assertThat(this.output.receive().getPayload()).isEqualTo("[0, 1, 2, 3, 4]");
 	}
 
 	private Map<String, Object> stubHeaders(int sequenceNumber, int sequenceSize, int correllationId) {

spring-integration-core/src/test/java/org/springframework/integration/aggregator/integration/AggregatorIntegrationTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2018 the original author or authors.
+ * Copyright 2002-2019 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -16,12 +16,7 @@
 
 package org.springframework.integration.aggregator.integration;
 
-import static org.hamcrest.Matchers.containsString;
-import static org.junit.Assert.assertEquals;
-import static org.junit.Assert.assertNotNull;
-import static org.junit.Assert.assertNull;
-import static org.junit.Assert.assertThat;
-import static org.junit.Assert.assertTrue;
+import static org.assertj.core.api.Assertions.assertThat;
 
 import java.util.Collection;
 import java.util.Collections;
@@ -95,8 +90,8 @@ public class AggregatorIntegrationTests {
 			input.send(new GenericMessage<>(i, headers));
 		}
 		Message<?> receive = output.receive(10000);
-		assertNotNull(receive);
-		assertEquals(1 + 2 + 3 + 4, receive.getPayload());
+		assertThat(receive).isNotNull();
+		assertThat(receive.getPayload()).isEqualTo(1 + 2 + 3 + 4);
 	}
 
 	@Test
@@ -105,21 +100,21 @@ public class AggregatorIntegrationTests {
 			Map<String, Object> headers = stubHeaders(i, 5, 1);
 			nonExpiringAggregatorInput.send(new GenericMessage<>(i, headers));
 		}
-		assertNotNull(output.receive(0));
+		assertThat(output.receive(0)).isNotNull();
 
-		assertNull(discard.receive(0));
+		assertThat(discard.receive(0)).isNull();
 
 		for (int i = 5; i < 10; i++) {
 			Map<String, Object> headers = stubHeaders(i, 5, 1);
 			nonExpiringAggregatorInput.send(new GenericMessage<>(i, headers));
 		}
-		assertNull(output.receive(0));
+		assertThat(output.receive(0)).isNull();
 
-		assertNotNull(discard.receive(0));
-		assertNotNull(discard.receive(0));
-		assertNotNull(discard.receive(0));
-		assertNotNull(discard.receive(0));
-		assertNotNull(discard.receive(0));
+		assertThat(discard.receive(0)).isNotNull();
+		assertThat(discard.receive(0)).isNotNull();
+		assertThat(discard.receive(0)).isNotNull();
+		assertThat(discard.receive(0)).isNotNull();
+		assertThat(discard.receive(0)).isNotNull();
 	}
 
 	@Test
@@ -128,17 +123,17 @@ public class AggregatorIntegrationTests {
 			Map<String, Object> headers = stubHeaders(i, 5, 1);
 			expiringAggregatorInput.send(new GenericMessage<>(i, headers));
 		}
-		assertNotNull(output.receive(0));
+		assertThat(output.receive(0)).isNotNull();
 
-		assertNull(discard.receive(0));
+		assertThat(discard.receive(0)).isNull();
 
 		for (int i = 5; i < 10; i++) {
 			Map<String, Object> headers = stubHeaders(i, 5, 1);
 			expiringAggregatorInput.send(new GenericMessage<>(i, headers));
 		}
-		assertNotNull(output.receive(0));
+		assertThat(output.receive(0)).isNotNull();
 
-		assertNull(discard.receive(0));
+		assertThat(discard.receive(0)).isNull();
 
 	}
 
@@ -155,9 +150,9 @@ public class AggregatorIntegrationTests {
 			while (n++ < 100 && mgs.getMessageGroupCount() > 0) {
 				Thread.sleep(100);
 			}
-			assertTrue("Group did not complete", n < 100);
-			assertNotNull(this.output.receive(10000));
-			assertNull(this.discard.receive(0));
+			assertThat(n < 100).as("Group did not complete").isTrue();
+			assertThat(this.output.receive(10000)).isNotNull();
+			assertThat(this.discard.receive(0)).isNull();
 		}
 	}
 
@@ -180,50 +175,50 @@ public class AggregatorIntegrationTests {
 				TestUtils.getPropertyValue(this.output, "queue", Queue.class).clear();
 			}
 		}
-		assertTrue("Group did not complete", n < 100);
+		assertThat(n < 100).as("Group did not complete").isTrue();
 		Message<?> receive = this.output.receive(10000);
-		assertNotNull(receive);
-		assertEquals(Collections.singletonList(1), receive.getPayload());
-		assertNull(this.discard.receive(0));
+		assertThat(receive).isNotNull();
+		assertThat(receive.getPayload()).isEqualTo(Collections.singletonList(1));
+		assertThat(this.discard.receive(0)).isNull();
 	}
 
 	@Test
 	public void testGroupTimeoutExpressionScheduling() {
 		// Since group-timeout-expression="size() >= 2 ? 100 : null". The first message won't be scheduled to 'forceComplete'
 		this.groupTimeoutExpressionAggregatorInput.send(new GenericMessage<>(1, stubHeaders(1, 6, 1)));
-		assertNull(this.output.receive(0));
-		assertNull(this.discard.receive(0));
+		assertThat(this.output.receive(0)).isNull();
+		assertThat(this.discard.receive(0)).isNull();
 
 		// As far as 'group.size() >= 2' it will be scheduled to 'forceComplete'
 		this.groupTimeoutExpressionAggregatorInput.send(new GenericMessage<>(2, stubHeaders(2, 6, 1)));
-		assertNull(this.output.receive(0));
+		assertThat(this.output.receive(0)).isNull();
 		Message<?> receive = this.output.receive(10000);
-		assertNotNull(receive);
-		assertEquals(2, ((Collection<?>) receive.getPayload()).size());
-		assertNull(this.discard.receive(0));
+		assertThat(receive).isNotNull();
+		assertThat(((Collection<?>) receive.getPayload()).size()).isEqualTo(2);
+		assertThat(this.discard.receive(0)).isNull();
 
 		// The same with these three messages
 		this.groupTimeoutExpressionAggregatorInput.send(new GenericMessage<>(3, stubHeaders(3, 6, 1)));
-		assertNull(this.output.receive(0));
-		assertNull(this.discard.receive(0));
+		assertThat(this.output.receive(0)).isNull();
+		assertThat(this.discard.receive(0)).isNull();
 
 		this.groupTimeoutExpressionAggregatorInput.send(new GenericMessage<>(4, stubHeaders(4, 6, 1)));
-		assertNull(this.output.receive(0));
-		assertNull(this.discard.receive(0));
+		assertThat(this.output.receive(0)).isNull();
+		assertThat(this.discard.receive(0)).isNull();
 
 		this.groupTimeoutExpressionAggregatorInput.send(new GenericMessage<>(5, stubHeaders(5, 6, 1)));
-		assertNull(this.output.receive(0));
+		assertThat(this.output.receive(0)).isNull();
 		receive = this.output.receive(10000);
-		assertNotNull(receive);
-		assertEquals(3, ((Collection<?>) receive.getPayload()).size());
-		assertNull(this.discard.receive(0));
+		assertThat(receive).isNotNull();
+		assertThat(((Collection<?>) receive.getPayload()).size()).isEqualTo(3);
+		assertThat(this.discard.receive(0)).isNull();
 
 		// The last message in the sequence - normal release by provided 'ReleaseStrategy'
 		this.groupTimeoutExpressionAggregatorInput.send(new GenericMessage<>(6, stubHeaders(6, 6, 1)));
 		receive = this.output.receive(10000);
-		assertNotNull(receive);
-		assertEquals(1, ((Collection<?>) receive.getPayload()).size());
-		assertNull(this.discard.receive(0));
+		assertThat(receive).isNotNull();
+		assertThat(((Collection<?>) receive.getPayload()).size()).isEqualTo(1);
+		assertThat(this.discard.receive(0)).isNull();
 	}
 
 	@Test
@@ -239,9 +234,9 @@ public class AggregatorIntegrationTests {
 			this.output.send(message);
 			this.zeroGroupTimeoutExpressionAggregatorInput.send(new GenericMessage<>(1, stubHeaders(1, 2, 1)));
 			ErrorMessage em = (ErrorMessage) this.errors.receive(10000);
-			assertNotNull(em);
-			assertThat(em.getPayload().getMessage().toLowerCase(),
-					containsString("failed to send message to channel 'output' within timeout: 10"));
+			assertThat(em).isNotNull();
+			assertThat(em.getPayload().getMessage().toLowerCase())
+					.contains("failed to send message to channel 'output' within timeout: 10");
 		}
 		finally {
 			this.output.purge(null);

spring-integration-core/src/test/java/org/springframework/integration/aggregator/integration/AggregatorSupportedUseCasesTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2016 the original author or authors.
+ * Copyright 2002-2019 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -16,9 +16,7 @@
 
 package org.springframework.integration.aggregator.integration;
 
-import static org.junit.Assert.assertEquals;
-import static org.junit.Assert.assertNotNull;
-import static org.junit.Assert.assertNull;
+import static org.assertj.core.api.Assertions.assertThat;
 
 import java.util.List;
 
@@ -56,19 +54,19 @@ public class AggregatorSupportedUseCasesTests {
 		for (int i = 0; i < 5; i++) {
 			defaultHandler.handleMessage(MessageBuilder.withPayload(i).setSequenceSize(5).setCorrelationId("A").setSequenceNumber(i).build());
 		}
-		assertEquals(5, ((List<?>) outputChannel.receive(0).getPayload()).size());
-		assertNull(discardChannel.receive(0));
-		assertEquals(0, store.getMessageGroup("A").getMessages().size());
+		assertThat(((List<?>) outputChannel.receive(0).getPayload()).size()).isEqualTo(5);
+		assertThat(discardChannel.receive(0)).isNull();
+		assertThat(store.getMessageGroup("A").getMessages().size()).isEqualTo(0);
 
 		// send another message with the same correlation id and see it in the discard channel
 		defaultHandler.handleMessage(MessageBuilder.withPayload("foo").setSequenceSize(5).setCorrelationId("A").setSequenceNumber(3).build());
-		assertNotNull(discardChannel.receive(0));
+		assertThat(discardChannel.receive(0)).isNotNull();
 
 		// expireMessageGroups from aggregator MessageStore and the messages should start accumulating again
 		store.expireMessageGroups(0);
 		defaultHandler.handleMessage(MessageBuilder.withPayload("foo").setSequenceSize(5).setCorrelationId("A").setSequenceNumber(3).build());
-		assertNull(discardChannel.receive(0));
-		assertEquals(1, store.getMessageGroup("A").getMessages().size());
+		assertThat(discardChannel.receive(0)).isNull();
+		assertThat(store.getMessageGroup("A").getMessages().size()).isEqualTo(1);
 	}
 
 	@Test
@@ -82,19 +80,19 @@ public class AggregatorSupportedUseCasesTests {
 		for (int i = 0; i < 5; i++) {
 			defaultHandler.handleMessage(MessageBuilder.withPayload(i).setCorrelationId("A").build());
 		}
-		assertEquals(5, ((List<?>) outputChannel.receive(0).getPayload()).size());
-		assertNull(discardChannel.receive(0));
-		assertEquals(0, store.getMessageGroup("A").getMessages().size());
+		assertThat(((List<?>) outputChannel.receive(0).getPayload()).size()).isEqualTo(5);
+		assertThat(discardChannel.receive(0)).isNull();
+		assertThat(store.getMessageGroup("A").getMessages().size()).isEqualTo(0);
 
 		// send another message with the same correlation id and see it in the discard channel
 		defaultHandler.handleMessage(MessageBuilder.withPayload("foo").setCorrelationId("A").build());
-		assertNotNull(discardChannel.receive(0));
+		assertThat(discardChannel.receive(0)).isNotNull();
 
 		// expireMessageGroups from aggregator MessageStore and the messages should start accumulating again
 		store.expireMessageGroups(0);
 		defaultHandler.handleMessage(MessageBuilder.withPayload("foo").setCorrelationId("A").build());
-		assertNull(discardChannel.receive(0));
-		assertEquals(1, store.getMessageGroup("A").getMessages().size());
+		assertThat(discardChannel.receive(0)).isNull();
+		assertThat(store.getMessageGroup("A").getMessages().size()).isEqualTo(1);
 	}
 
 	@Test
@@ -108,11 +106,11 @@ public class AggregatorSupportedUseCasesTests {
 		for (int i = 0; i < 5; i++) {
 			defaultHandler.handleMessage(MessageBuilder.withPayload(i).setCorrelationId("A").build());
 		}
-		assertEquals(1, ((List<?>) outputChannel.receive(0).getPayload()).size());
-		assertNotNull(discardChannel.receive(0));
-		assertNotNull(discardChannel.receive(0));
-		assertNotNull(discardChannel.receive(0));
-		assertNotNull(discardChannel.receive(0));
+		assertThat(((List<?>) outputChannel.receive(0).getPayload()).size()).isEqualTo(1);
+		assertThat(discardChannel.receive(0)).isNotNull();
+		assertThat(discardChannel.receive(0)).isNotNull();
+		assertThat(discardChannel.receive(0)).isNotNull();
+		assertThat(discardChannel.receive(0)).isNotNull();
 	}
 
 	@Test
@@ -127,9 +125,9 @@ public class AggregatorSupportedUseCasesTests {
 		for (int i = 0; i < 10; i++) {
 			defaultHandler.handleMessage(MessageBuilder.withPayload(i).setCorrelationId("A").build());
 		}
-		assertEquals(5, ((List<?>) outputChannel.receive(0).getPayload()).size());
-		assertEquals(5, ((List<?>) outputChannel.receive(0).getPayload()).size());
-		assertNull(discardChannel.receive(0));
+		assertThat(((List<?>) outputChannel.receive(0).getPayload()).size()).isEqualTo(5);
+		assertThat(((List<?>) outputChannel.receive(0).getPayload()).size()).isEqualTo(5);
+		assertThat(discardChannel.receive(0)).isNull();
 	}
 
 	@Test
@@ -144,10 +142,10 @@ public class AggregatorSupportedUseCasesTests {
 		for (int i = 0; i < 12; i++) {
 			defaultHandler.handleMessage(MessageBuilder.withPayload(i).setCorrelationId("A").build());
 		}
-		assertEquals(5, ((List<?>) outputChannel.receive(0).getPayload()).size());
-		assertEquals(5, ((List<?>) outputChannel.receive(0).getPayload()).size());
-		assertNull(discardChannel.receive(0));
-		assertEquals(2, store.getMessageGroup("A").getMessages().size());
+		assertThat(((List<?>) outputChannel.receive(0).getPayload()).size()).isEqualTo(5);
+		assertThat(((List<?>) outputChannel.receive(0).getPayload()).size()).isEqualTo(5);
+		assertThat(discardChannel.receive(0)).isNull();
+		assertThat(store.getMessageGroup("A").getMessages().size()).isEqualTo(2);
 	}
 
 	private class SampleSizeReleaseStrategy implements ReleaseStrategy {

spring-integration-core/src/test/java/org/springframework/integration/aggregator/integration/AnnotationAggregatorTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2016 the original author or authors.
+ * Copyright 2002-2019 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -16,7 +16,7 @@
 
 package org.springframework.integration.aggregator.integration;
 
-import static org.junit.Assert.assertTrue;
+import static org.assertj.core.api.Assertions.assertThat;
 
 import java.util.List;
 
@@ -55,8 +55,8 @@ public class AnnotationAggregatorTests {
 		@SuppressWarnings("unchecked")
 		Message<String> result = (Message<String>) output.receive();
 		String payload = result.getPayload();
-		assertTrue("Wrong payload: " + payload, payload.matches(".*payload.*?=a.*"));
-		assertTrue("Wrong payload: " + payload, payload.matches(".*payload.*?=b.*"));
+		assertThat(payload.matches(".*payload.*?=a.*")).as("Wrong payload: " + payload).isTrue();
+		assertThat(payload.matches(".*payload.*?=b.*")).as("Wrong payload: " + payload).isTrue();
 	}
 
 	@SuppressWarnings("unused")

spring-integration-core/src/test/java/org/springframework/integration/aggregator/integration/DefaultMessageAggregatorIntegrationTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2018 the original author or authors.
+ * Copyright 2002-2019 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -16,10 +16,7 @@
 
 package org.springframework.integration.aggregator.integration;
 
-import static org.hamcrest.CoreMatchers.instanceOf;
-import static org.hamcrest.CoreMatchers.is;
-import static org.junit.Assert.assertThat;
-import static org.junit.Assert.assertTrue;
+import static org.assertj.core.api.Assertions.assertThat;
 
 import java.util.Arrays;
 import java.util.HashMap;
@@ -64,9 +61,9 @@ public class DefaultMessageAggregatorIntegrationTests {
 			this.input.send(new GenericMessage<>(i, headers));
 		}
 		Object payload = this.output.receive().getPayload();
-		assertThat(payload, is(instanceOf(List.class)));
-		assertTrue(payload + " doesn't contain all of {0,1,2,3,4}",
-				((List) payload).containsAll(Arrays.asList(0, 1, 2, 3, 4)));
+		assertThat(payload).isInstanceOf(List.class);
+		assertThat(((List) payload).containsAll(Arrays.asList(0, 1, 2, 3, 4)))
+				.as(payload + " doesn't contain all of {0,1,2,3,4}").isTrue();
 	}
 
 

spring-integration-core/src/test/java/org/springframework/integration/aggregator/integration/MethodInvokingAggregatorReturningMessageTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2018 the original author or authors.
+ * Copyright 2002-2019 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -16,7 +16,7 @@
 
 package org.springframework.integration.aggregator.integration;
 
-import static org.junit.Assert.assertFalse;
+import static org.assertj.core.api.Assertions.assertThat;
 
 import java.util.Collections;
 import java.util.List;
@@ -58,7 +58,7 @@ public class MethodInvokingAggregatorReturningMessageTests {
 		List<String> payload = Collections.singletonList("test");
 		this.pojoInput.send(MessageBuilder.withPayload(payload).build());
 		Message<?> result = this.pojoOutput.receive();
-		assertFalse(Message.class.isAssignableFrom(result.getPayload().getClass()));
+		assertThat(Message.class.isAssignableFrom(result.getPayload().getClass())).isFalse();
 	}
 
 	@Test
@@ -66,7 +66,7 @@ public class MethodInvokingAggregatorReturningMessageTests {
 		List<String> payload = Collections.singletonList("test");
 		this.defaultInput.send(MessageBuilder.withPayload(payload).build());
 		Message<?> result = this.defaultOutput.receive();
-		assertFalse(Message.class.isAssignableFrom(result.getPayload().getClass()));
+		assertThat(Message.class.isAssignableFrom(result.getPayload().getClass())).isFalse();
 	}
 
 

spring-integration-core/src/test/java/org/springframework/integration/aggregator/integration/ResequencerIntegrationTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2017 the original author or authors.
+ * Copyright 2002-2019 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -16,11 +16,7 @@
 
 package org.springframework.integration.aggregator.integration;
 
-import static org.junit.Assert.assertEquals;
-import static org.junit.Assert.assertFalse;
-import static org.junit.Assert.assertNotNull;
-import static org.junit.Assert.assertNull;
-import static org.junit.Assert.assertTrue;
+import static org.assertj.core.api.Assertions.assertThat;
 
 import org.junit.Test;
 import org.junit.runner.RunWith;
@@ -77,45 +73,45 @@ public class ResequencerIntegrationTests {
 		Message<?> message6 = MessageBuilder.withPayload("6").setCorrelationId("A").setSequenceNumber(6).build();
 
 		inputChannel.send(message3);
-		assertNull(outputChannel.receive(0));
+		assertThat(outputChannel.receive(0)).isNull();
 
 		inputChannel.send(message1);
 		message1 = outputChannel.receive(0);
-		assertNotNull(message1);
-		assertEquals(1, new IntegrationMessageHeaderAccessor(message1).getSequenceNumber());
-		assertFalse(message1.getHeaders().containsKey("foo"));
+		assertThat(message1).isNotNull();
+		assertThat(new IntegrationMessageHeaderAccessor(message1).getSequenceNumber()).isEqualTo(1);
+		assertThat(message1.getHeaders().containsKey("foo")).isFalse();
 
 		inputChannel.send(message2);
 		message2 = outputChannel.receive(0);
 		message3 = outputChannel.receive(0);
-		assertNotNull(message2);
-		assertNotNull(message3);
-		assertEquals(2, new IntegrationMessageHeaderAccessor(message2).getSequenceNumber());
-		assertTrue(message2.getHeaders().containsKey("foo"));
-		assertEquals(3, new IntegrationMessageHeaderAccessor(message3).getSequenceNumber());
-		assertFalse(message3.getHeaders().containsKey("foo"));
+		assertThat(message2).isNotNull();
+		assertThat(message3).isNotNull();
+		assertThat(new IntegrationMessageHeaderAccessor(message2).getSequenceNumber()).isEqualTo(2);
+		assertThat(message2.getHeaders().containsKey("foo")).isTrue();
+		assertThat(new IntegrationMessageHeaderAccessor(message3).getSequenceNumber()).isEqualTo(3);
+		assertThat(message3.getHeaders().containsKey("foo")).isFalse();
 
 		inputChannel.send(message5);
-		assertNull(outputChannel.receive(0));
+		assertThat(outputChannel.receive(0)).isNull();
 
 		inputChannel.send(message6);
-		assertNull(outputChannel.receive(0));
+		assertThat(outputChannel.receive(0)).isNull();
 
 		inputChannel.send(message4);
 		message4 = outputChannel.receive(0);
 		message5 = outputChannel.receive(0);
 		message6 = outputChannel.receive(0);
-		assertNotNull(message4);
-		assertNotNull(message5);
-		assertNotNull(message6);
-		assertEquals(4, new IntegrationMessageHeaderAccessor(message4).getSequenceNumber());
-		assertTrue(message4.getHeaders().containsKey("foo"));
-		assertEquals(5, new IntegrationMessageHeaderAccessor(message5).getSequenceNumber());
-		assertFalse(message5.getHeaders().containsKey("foo"));
-		assertEquals(6, new IntegrationMessageHeaderAccessor(message6).getSequenceNumber());
-		assertFalse(message6.getHeaders().containsKey("foo"));
+		assertThat(message4).isNotNull();
+		assertThat(message5).isNotNull();
+		assertThat(message6).isNotNull();
+		assertThat(new IntegrationMessageHeaderAccessor(message4).getSequenceNumber()).isEqualTo(4);
+		assertThat(message4.getHeaders().containsKey("foo")).isTrue();
+		assertThat(new IntegrationMessageHeaderAccessor(message5).getSequenceNumber()).isEqualTo(5);
+		assertThat(message5.getHeaders().containsKey("foo")).isFalse();
+		assertThat(new IntegrationMessageHeaderAccessor(message6).getSequenceNumber()).isEqualTo(6);
+		assertThat(message6.getHeaders().containsKey("foo")).isFalse();
 
-		assertEquals(0, store.getMessageGroup("A").getMessages().size());
+		assertThat(store.getMessageGroup("A").getMessages().size()).isEqualTo(0);
 	}
 
 	@Test
@@ -131,13 +127,13 @@ public class ResequencerIntegrationTests {
 		Message<?> message3 = MessageBuilder.withPayload("3").setCorrelationId("A").setSequenceNumber(3).build();
 
 		inputChannel.send(message3);
-		assertNull(outputChannel.receive(0));
+		assertThat(outputChannel.receive(0)).isNull();
 		inputChannel.send(message1);
-		assertNotNull(outputChannel.receive(0));
+		assertThat(outputChannel.receive(0)).isNotNull();
 		inputChannel.send(message2);
-		assertNotNull(outputChannel.receive(0));
-		assertNotNull(outputChannel.receive(0));
-		assertEquals(0, store.getMessageGroup("A").getMessages().size());
+		assertThat(outputChannel.receive(0)).isNotNull();
+		assertThat(outputChannel.receive(0)).isNotNull();
+		assertThat(store.getMessageGroup("A").getMessages().size()).isEqualTo(0);
 	}
 
 	@Test
@@ -147,8 +143,8 @@ public class ResequencerIntegrationTests {
 		Message<?> message1 = MessageBuilder.withPayload("1").setCorrelationId("A").setSequenceNumber(1).build();
 		inputChannel.send(message1);
 		message1 = outputChannel.receive(0);
-		assertNotNull(message1);
-		assertEquals(1, new IntegrationMessageHeaderAccessor(message1).getSequenceNumber());
+		assertThat(message1).isNotNull();
+		assertThat(new IntegrationMessageHeaderAccessor(message1).getSequenceNumber()).isEqualTo(1);
 	}
 
 }

spring-integration-core/src/test/java/org/springframework/integration/aggregator/scenarios/AggregationResendTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2018 the original author or authors.
+ * Copyright 2002-2019 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -16,10 +16,11 @@
 
 package org.springframework.integration.aggregator.scenarios;
 
+import static org.assertj.core.api.Assertions.assertThat;
+
 import java.util.ArrayList;
 import java.util.List;
 
-import org.junit.Assert;
 import org.junit.Ignore;
 import org.junit.Test;
 import org.junit.runner.RunWith;
@@ -99,7 +100,7 @@ public class AggregationResendTests {
 		}
 		while (null != replyMessage);
 
-		Assert.assertEquals(1, messageCount);
+		assertThat(messageCount).isEqualTo(1);
 	}
 
 }

spring-integration-core/src/test/java/org/springframework/integration/aggregator/scenarios/AggregatorReplyChannelTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2018 the original author or authors.
+ * Copyright 2002-2019 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -16,10 +16,7 @@
 
 package org.springframework.integration.aggregator.scenarios;
 
-import static org.junit.Assert.assertEquals;
-import static org.junit.Assert.assertNotNull;
-import static org.junit.Assert.assertNull;
-import static org.junit.Assert.assertTrue;
+import static org.assertj.core.api.Assertions.assertThat;
 
 import java.util.ArrayList;
 import java.util.List;
@@ -73,15 +70,15 @@ public class AggregatorReplyChannelTests {
 	}
 
 	private void verifyReply(Message<?> message) {
-		assertNull(this.output.receive(0));
+		assertThat(this.output.receive(0)).isNull();
 		this.input.send(message);
 		Message<?> result = this.output.receive(0);
-		assertNotNull(result);
-		assertTrue(result.getPayload() instanceof List);
+		assertThat(result).isNotNull();
+		assertThat(result.getPayload() instanceof List).isTrue();
 		List<?> resultList = (List<?>) result.getPayload();
-		assertEquals(2, resultList.size());
-		assertTrue(resultList.contains("foo"));
-		assertTrue(resultList.contains("bar"));
+		assertThat(resultList.size()).isEqualTo(2);
+		assertThat(resultList.contains("foo")).isTrue();
+		assertThat(resultList.contains("bar")).isTrue();
 	}
 
 }

spring-integration-core/src/test/java/org/springframework/integration/aggregator/scenarios/AggregatorWithCustomReleaseStrategyTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2018 the original author or authors.
+ * Copyright 2002-2019 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -16,8 +16,7 @@
 
 package org.springframework.integration.aggregator.scenarios;
 
-import static org.junit.Assert.assertEquals;
-import static org.junit.Assert.assertTrue;
+import static org.assertj.core.api.Assertions.assertThat;
 
 import java.util.concurrent.CountDownLatch;
 import java.util.concurrent.ExecutorService;
@@ -92,7 +91,8 @@ public class AggregatorWithCustomReleaseStrategyTests {
 			});
 		}
 
-		assertTrue("Sends failed to complete: " + latch.getCount() + " remain", latch.await(120, TimeUnit.SECONDS));
+		assertThat(latch.await(120, TimeUnit.SECONDS)).as("Sends failed to complete: " + latch.getCount() + " remain")
+				.isTrue();
 
 		Message<?> message = resultChannel.receive(1000);
 		int counter = 0;
@@ -100,7 +100,7 @@ public class AggregatorWithCustomReleaseStrategyTests {
 			counter++;
 			message = resultChannel.receive(1000);
 		}
-		assertEquals(600, counter);
+		assertThat(counter).isEqualTo(600);
 		context.close();
 	}
 
@@ -127,14 +127,15 @@ public class AggregatorWithCustomReleaseStrategyTests {
 			});
 		}
 
-		assertTrue("Sends failed to complete: " + latch.getCount() + " remain", latch.await(60, TimeUnit.SECONDS));
+		assertThat(latch.await(60, TimeUnit.SECONDS)).as("Sends failed to complete: " + latch.getCount() + " remain")
+				.isTrue();
 
 		Message<?> message = resultChannel.receive(1000);
 		int counter = 0;
 		while (message != null && ++counter < 7200) {
 			message = resultChannel.receive(1000);
 		}
-		assertEquals(7200, counter);
+		assertThat(counter).isEqualTo(7200);
 		context.close();
 	}
 

spring-integration-core/src/test/java/org/springframework/integration/aggregator/scenarios/NestedAggregationTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2018 the original author or authors.
+ * Copyright 2002-2019 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -16,8 +16,7 @@
 
 package org.springframework.integration.aggregator.scenarios;
 
-import static org.junit.Assert.assertEquals;
-import static org.junit.Assert.assertNotNull;
+import static org.assertj.core.api.Assertions.assertThat;
 
 import java.util.Arrays;
 import java.util.List;
@@ -55,16 +54,16 @@ public class NestedAggregationTests {
 						Arrays.asList("foo", "bar", "spam"),
 						Arrays.asList("bar", "foo")));
 		List<String> result = sendAndReceiveMessage(splitter, 2000, input);
-		assertNotNull("Expected result and got null", result);
-		assertEquals("[[foo, bar, spam], [bar, foo]]", result.toString());
+		assertThat(result).as("Expected result and got null").isNotNull();
+		assertThat(result.toString()).isEqualTo("[[foo, bar, spam], [bar, foo]]");
 	}
 
 	@Test
 	public void testAggregatorWithNestedRouter() {
 		Message<?> input = new GenericMessage<>(Arrays.asList("bar", "foo"));
 		List<String> result = sendAndReceiveMessage(router, 2000, input);
-		assertNotNull("Expected result and got null", result);
-		assertEquals("[[bar, foo], [bar, foo]]", result.toString());
+		assertThat(result).as("Expected result and got null").isNotNull();
+		assertThat(result.toString()).isEqualTo("[[bar, foo], [bar, foo]]");
 	}
 
 	private List<String> sendAndReceiveMessage(DirectChannel channel, int timeout, Message<?> input) {

spring-integration-core/src/test/java/org/springframework/integration/aggregator/scenarios/PartialSequencesWithGapsTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2016 the original author or authors.
+ * Copyright 2002-2019 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -16,9 +16,7 @@
 
 package org.springframework.integration.aggregator.scenarios;
 
-import static org.hamcrest.Matchers.is;
-import static org.hamcrest.Matchers.nullValue;
-import static org.junit.Assert.assertThat;
+import static org.assertj.core.api.Assertions.assertThat;
 
 import java.util.Queue;
 import java.util.concurrent.ArrayBlockingQueue;
@@ -63,14 +61,14 @@ public class PartialSequencesWithGapsTests {
 		in.send(message(6, 6));
 		in.send(message(2, 6));
 		in.send(message(1, 6));
-		assertThat(new IntegrationMessageHeaderAccessor(received.poll()).getSequenceNumber(), is(1));
-		assertThat(new IntegrationMessageHeaderAccessor(received.poll()).getSequenceNumber(), is(2));
+		assertThat(new IntegrationMessageHeaderAccessor(received.poll()).getSequenceNumber()).isEqualTo(1);
+		assertThat(new IntegrationMessageHeaderAccessor(received.poll()).getSequenceNumber()).isEqualTo(2);
 		received.poll();
 		received.poll();
 		in.send(message(5, 6));
-		assertThat(received.poll(), is(nullValue()));
+		assertThat(received.poll()).isNull();
 		in.send(message(4, 6));
-		assertThat(received.poll(), is(nullValue()));
+		assertThat(received.poll()).isNull();
 	}
 
 	private Message<?> message(int sequenceNumber, int sequenceSize) {

spring-integration-core/src/test/java/org/springframework/integration/aop/AnnotationConfigRegistrationTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2018 the original author or authors.
+ * Copyright 2002-2019 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -16,7 +16,8 @@
 
 package org.springframework.integration.aop;
 
-import org.junit.Assert;
+import static org.assertj.core.api.Assertions.assertThat;
+
 import org.junit.Test;
 import org.junit.runner.RunWith;
 
@@ -53,21 +54,21 @@ public class AnnotationConfigRegistrationTests {
 	@Test // INT-1200
 	public void verifyInterception() {
 		String name = this.testBean.setName("John", "Doe", 123);
-		Assert.assertNotNull(name);
+		assertThat(name).isNotNull();
 		Message<?> message = this.annotationConfigRegistrationTest.receive(0);
-		Assert.assertNotNull(message);
-		Assert.assertEquals("John DoeDoe", message.getPayload());
-		Assert.assertEquals(123, message.getHeaders().get("x"));
+		assertThat(message).isNotNull();
+		assertThat(message.getPayload()).isEqualTo("John DoeDoe");
+		assertThat(message.getHeaders().get("x")).isEqualTo(123);
 	}
 
 	@Test
 	public void defaultChannel() {
 		String result = this.testBean.exclaim("hello");
-		Assert.assertNotNull(result);
-		Assert.assertEquals("HELLO!!!", result);
+		assertThat(result).isNotNull();
+		assertThat(result).isEqualTo("HELLO!!!");
 		Message<?> message = this.defaultChannel.receive(0);
-		Assert.assertNotNull(message);
-		Assert.assertEquals("HELLO!!!", message.getPayload());
+		assertThat(message).isNotNull();
+		assertThat(message.getPayload()).isEqualTo("HELLO!!!");
 	}
 
 

spring-integration-core/src/test/java/org/springframework/integration/aop/MessagePublishingAnnotationUsageTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2018 the original author or authors.
+ * Copyright 2002-2019 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -16,8 +16,7 @@
 
 package org.springframework.integration.aop;
 
-import static org.junit.Assert.assertEquals;
-import static org.junit.Assert.assertNotNull;
+import static org.assertj.core.api.Assertions.assertThat;
 
 import org.junit.Test;
 import org.junit.runner.RunWith;
@@ -52,32 +51,32 @@ public class MessagePublishingAnnotationUsageTests {
 	@Test
 	public void headerWithExplicitName() {
 		String name = this.testBean.defaultPayload("John", "Doe");
-		assertNotNull(name);
+		assertThat(name).isNotNull();
 		Message<?> message = this.channel.receive(1000);
-		assertNotNull(message);
-		assertEquals("John Doe", message.getPayload());
-		assertEquals("Doe", message.getHeaders().get("last"));
+		assertThat(message).isNotNull();
+		assertThat(message.getPayload()).isEqualTo("John Doe");
+		assertThat(message.getHeaders().get("last")).isEqualTo("Doe");
 	}
 
 	@Test
 	public void headerWithImplicitName() {
 		String name = this.testBean.defaultPayloadButExplicitAnnotation("John", "Doe");
-		assertNotNull(name);
+		assertThat(name).isNotNull();
 		Message<?> message = this.channel.receive(1000);
-		assertNotNull(message);
-		assertEquals("John Doe", message.getPayload());
-		assertEquals("Doe", message.getHeaders().get("lname"));
+		assertThat(message).isNotNull();
+		assertThat(message.getPayload()).isEqualTo("John Doe");
+		assertThat(message.getHeaders().get("lname")).isEqualTo("Doe");
 	}
 
 	@Test
 	public void payloadAsArgument() {
 		String name = this.testBean.argumentAsPayload("John", "Doe");
-		assertNotNull(name);
-		assertEquals("John Doe", name);
+		assertThat(name).isNotNull();
+		assertThat(name).isEqualTo("John Doe");
 		Message<?> message = this.channel.receive(1000);
-		assertNotNull(message);
-		assertEquals("John", message.getPayload());
-		assertEquals("Doe", message.getHeaders().get("lname"));
+		assertThat(message).isNotNull();
+		assertThat(message.getPayload()).isEqualTo("John");
+		assertThat(message.getHeaders().get("lname")).isEqualTo("Doe");
 	}
 
 

spring-integration-core/src/test/java/org/springframework/integration/aop/MessagePublishingInterceptorTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2018 the original author or authors.
+ * Copyright 2002-2019 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -16,8 +16,7 @@
 
 package org.springframework.integration.aop;
 
-import static org.junit.Assert.assertEquals;
-import static org.junit.Assert.assertNotNull;
+import static org.assertj.core.api.Assertions.assertThat;
 
 import java.lang.reflect.Method;
 import java.util.HashMap;
@@ -68,8 +67,8 @@ public class MessagePublishingInterceptorTests {
 		TestBean proxy = (TestBean) pf.getProxy();
 		proxy.test();
 		Message<?> message = testChannel.receive(0);
-		assertNotNull(message);
-		assertEquals("test-foo", message.getPayload());
+		assertThat(message).isNotNull();
+		assertThat(message.getPayload()).isEqualTo("test-foo");
 	}
 
 	@Test
@@ -96,10 +95,10 @@ public class MessagePublishingInterceptorTests {
 		TestBean proxy = (TestBean) pf.getProxy();
 		proxy.test();
 		Message<?> message = testChannel.receive(0);
-		assertNotNull(message);
-		assertEquals("foo", message.getPayload());
-		assertEquals("foo", message.getHeaders().get("bar"));
-		assertEquals("oleg", message.getHeaders().get("name"));
+		assertThat(message).isNotNull();
+		assertThat(message.getPayload()).isEqualTo("foo");
+		assertThat(message.getHeaders().get("bar")).isEqualTo("foo");
+		assertThat(message.getHeaders().get("name")).isEqualTo("oleg");
 	}
 
 

spring-integration-core/src/test/java/org/springframework/integration/aop/MessagePublishingInterceptorUsageTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2018 the original author or authors.
+ * Copyright 2002-2019 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -16,7 +16,8 @@
 
 package org.springframework.integration.aop;
 
-import org.junit.Assert;
+import static org.assertj.core.api.Assertions.assertThat;
+
 import org.junit.Test;
 import org.junit.runner.RunWith;
 
@@ -46,11 +47,11 @@ public class MessagePublishingInterceptorUsageTests {
 	@Test
 	public void demoMessagePublishingInterceptor() {
 		String name = this.testBean.setName("John", "Doe");
-		Assert.assertNotNull(name);
+		assertThat(name).isNotNull();
 		Message<?> message = this.channel.receive(1000);
-		Assert.assertNotNull(message);
-		Assert.assertEquals("John Doe", message.getPayload());
-		Assert.assertEquals("bar", message.getHeaders().get("foo"));
+		assertThat(message).isNotNull();
+		assertThat(message.getPayload()).isEqualTo("John Doe");
+		assertThat(message.getHeaders().get("foo")).isEqualTo("bar");
 	}
 
 

spring-integration-core/src/test/java/org/springframework/integration/aop/MethodAnnotationPublisherMetadataSourceTests.java

@@ -16,10 +16,7 @@
 
 package org.springframework.integration.aop;
 
-import static org.hamcrest.Matchers.instanceOf;
-import static org.junit.Assert.assertEquals;
-import static org.junit.Assert.assertNotNull;
-import static org.junit.Assert.assertThat;
+import static org.assertj.core.api.Assertions.assertThat;
 
 import java.lang.annotation.Retention;
 import java.lang.annotation.RetentionPolicy;
@@ -52,8 +49,8 @@ public class MethodAnnotationPublisherMetadataSourceTests {
 		Method method = getMethod("methodWithChannelAndExplicitReturnAsPayload");
 		String channelName = source.getChannelName(method);
 		Expression payloadExpression = source.getExpressionForPayload(method);
-		assertEquals("foo", channelName);
-		assertEquals("#return", payloadExpression.getExpressionString());
+		assertThat(channelName).isEqualTo("foo");
+		assertThat(payloadExpression.getExpressionString()).isEqualTo("#return");
 	}
 
 	@Test
@@ -61,40 +58,40 @@ public class MethodAnnotationPublisherMetadataSourceTests {
 		Method method = getMethod("methodWithChannelAndEmptyPayloadAnnotation");
 		String channelName = source.getChannelName(method);
 		Expression payloadExpression = source.getExpressionForPayload(method);
-		assertEquals("foo", channelName);
-		assertEquals("#return", payloadExpression.getExpressionString());
+		assertThat(channelName).isEqualTo("foo");
+		assertThat(payloadExpression.getExpressionString()).isEqualTo("#return");
 	}
 
 	@Test
 	public void payloadButNoHeaders() {
 		Method method = getMethod("methodWithPayloadAnnotation", String.class, int.class);
 		String expressionString = source.getExpressionForPayload(method).getExpressionString();
-		assertEquals("testExpression1", expressionString);
+		assertThat(expressionString).isEqualTo("testExpression1");
 		Map<String, Expression> headerMap = source.getExpressionsForHeaders(method);
-		assertNotNull(headerMap);
-		assertEquals(0, headerMap.size());
+		assertThat(headerMap).isNotNull();
+		assertThat(headerMap.size()).isEqualTo(0);
 	}
 
 	@Test
 	public void payloadAndHeaders() {
 		Method method = getMethod("methodWithHeaderAnnotations", String.class, String.class, String.class);
 		String expressionString = source.getExpressionForPayload(method).getExpressionString();
-		assertEquals("testExpression2", expressionString);
+		assertThat(expressionString).isEqualTo("testExpression2");
 		Map<String, Expression> headerMap = source.getExpressionsForHeaders(method);
-		assertNotNull(headerMap);
-		assertEquals(2, headerMap.size());
-		assertEquals("#args[1]", headerMap.get("foo").getExpressionString());
-		assertEquals("#args[2]", headerMap.get("bar").getExpressionString());
+		assertThat(headerMap).isNotNull();
+		assertThat(headerMap.size()).isEqualTo(2);
+		assertThat(headerMap.get("foo").getExpressionString()).isEqualTo("#args[1]");
+		assertThat(headerMap.get("bar").getExpressionString()).isEqualTo("#args[2]");
 	}
 
 	@Test
 	public void expressionsAreConcurrentHashMap() {
-		assertThat("Expressions should be concurrent to allow startup",
-				ReflectionTestUtils.getField(source, "channels"), instanceOf(ConcurrentHashMap.class));
-		assertThat("Expressions should be concurrent to allow startup",
-				ReflectionTestUtils.getField(source, "payloadExpressions"), instanceOf(ConcurrentHashMap.class));
-		assertThat("Expressions should be concurrent to allow startup",
-				ReflectionTestUtils.getField(source, "headersExpressions"), instanceOf(ConcurrentHashMap.class));
+		assertThat(ReflectionTestUtils.getField(source, "channels"))
+				.as("Expressions should be concurrent to allow startup").isInstanceOf(ConcurrentHashMap.class);
+		assertThat(ReflectionTestUtils.getField(source, "payloadExpressions"))
+				.as("Expressions should be concurrent to allow startup").isInstanceOf(ConcurrentHashMap.class);
+		assertThat(ReflectionTestUtils.getField(source, "headersExpressions"))
+				.as("Expressions should be concurrent to allow startup").isInstanceOf(ConcurrentHashMap.class);
 	}
 
 	@Test
@@ -102,8 +99,8 @@ public class MethodAnnotationPublisherMetadataSourceTests {
 		Method method = getMethod("methodWithVoidReturnAndMethodNameAsPayload");
 		String channelName = source.getChannelName(method);
 		String payloadExpression = source.getExpressionForPayload(method).getExpressionString();
-		assertEquals("foo", channelName);
-		assertEquals("#method", payloadExpression);
+		assertThat(channelName).isEqualTo("foo");
+		assertThat(payloadExpression).isEqualTo("#method");
 	}
 
 	@Test(expected = IllegalArgumentException.class)
@@ -116,7 +113,7 @@ public class MethodAnnotationPublisherMetadataSourceTests {
 	public void voidReturnAndParameterPayloadAnnotation() {
 		Method method = getMethod("methodWithVoidReturnAndParameterPayloadAnnotation", String.class);
 		String payloadExpression = source.getExpressionForPayload(method).getExpressionString();
-		assertEquals("#args[0]", payloadExpression);
+		assertThat(payloadExpression).isEqualTo("#args[0]");
 	}
 
 	@Test(expected = IllegalArgumentException.class)
@@ -129,14 +126,14 @@ public class MethodAnnotationPublisherMetadataSourceTests {
 	public void explicitAnnotationAttributeOverride() {
 		Method method = getMethod("methodWithExplicitAnnotationAttributeOverride");
 		String channelName = source.getChannelName(method);
-		assertEquals("foo", channelName);
+		assertThat(channelName).isEqualTo("foo");
 	}
 
 	@Test
 	public void explicitAnnotationAttributeOverrideOnDeclaringClass() {
 		Method method = getMethodFromTestClass("methodWithAnnotationOnTheDeclaringClass");
 		String channelName = source.getChannelName(method);
-		assertEquals("bar", channelName);
+		assertThat(channelName).isEqualTo("bar");
 	}
 
 	private static Method getMethodFromTestClass(String name, Class<?>... params) {

spring-integration-core/src/test/java/org/springframework/integration/aop/PublisherAnnotationAdvisorTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2018 the original author or authors.
+ * Copyright 2002-2019 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -16,8 +16,7 @@
 
 package org.springframework.integration.aop;
 
-import static org.junit.Assert.assertEquals;
-import static org.junit.Assert.assertNotNull;
+import static org.assertj.core.api.Assertions.assertThat;
 
 import java.lang.annotation.ElementType;
 import java.lang.annotation.Retention;
@@ -60,8 +59,8 @@ public class PublisherAnnotationAdvisorTests {
 		TestVoidBean proxy = (TestVoidBean) pf.getProxy();
 		proxy.testVoidMethod("foo");
 		Message<?> message = testChannel.receive(0);
-		assertNotNull(message);
-		assertEquals("foo", message.getPayload());
+		assertThat(message).isNotNull();
+		assertThat(message.getPayload()).isEqualTo("foo");
 	}
 
 	@Test
@@ -74,8 +73,8 @@ public class PublisherAnnotationAdvisorTests {
 		TestBean proxy = (TestBean) pf.getProxy();
 		proxy.test();
 		Message<?> message = testChannel.receive(0);
-		assertNotNull(message);
-		assertEquals("foo", message.getPayload());
+		assertThat(message).isNotNull();
+		assertThat(message.getPayload()).isEqualTo("foo");
 	}
 
 	@Test
@@ -88,8 +87,8 @@ public class PublisherAnnotationAdvisorTests {
 		TestBean proxy = (TestBean) pf.getProxy();
 		proxy.test();
 		Message<?> message = testChannel.receive(0);
-		assertNotNull(message);
-		assertEquals("foo", message.getPayload());
+		assertThat(message).isNotNull();
+		assertThat(message.getPayload()).isEqualTo("foo");
 	}
 
 	@Test
@@ -102,8 +101,8 @@ public class PublisherAnnotationAdvisorTests {
 		TestBean proxy = (TestBean) pf.getProxy();
 		proxy.test();
 		Message<?> message = testMetaChannel.receive(0);
-		assertNotNull(message);
-		assertEquals("foo", message.getPayload());
+		assertThat(message).isNotNull();
+		assertThat(message.getPayload()).isEqualTo("foo");
 	}
 
 	@Test
@@ -116,8 +115,8 @@ public class PublisherAnnotationAdvisorTests {
 		TestBean proxy = (TestBean) pf.getProxy();
 		proxy.test();
 		Message<?> message = testMetaChannel.receive(0);
-		assertNotNull(message);
-		assertEquals("foo", message.getPayload());
+		assertThat(message).isNotNull();
+		assertThat(message.getPayload()).isEqualTo("foo");
 	}
 
 	@Test
@@ -130,8 +129,8 @@ public class PublisherAnnotationAdvisorTests {
 		TestVoidBean proxy = (TestVoidBean) pf.getProxy();
 		proxy.testVoidMethod("foo");
 		Message<?> message = testChannel.receive(0);
-		assertNotNull(message);
-		assertEquals("foo", message.getPayload());
+		assertThat(message).isNotNull();
+		assertThat(message.getPayload()).isEqualTo("foo");
 	}
 
 	@Test
@@ -144,8 +143,8 @@ public class PublisherAnnotationAdvisorTests {
 		TestBean proxy = (TestBean) pf.getProxy();
 		proxy.test();
 		Message<?> message = testChannel.receive(0);
-		assertNotNull(message);
-		assertEquals("foo", message.getPayload());
+		assertThat(message).isNotNull();
+		assertThat(message.getPayload()).isEqualTo("foo");
 	}
 
 	@Test
@@ -158,8 +157,8 @@ public class PublisherAnnotationAdvisorTests {
 		TestBean proxy = (TestBean) pf.getProxy();
 		proxy.test();
 		Message<?> message = testChannel.receive(0);
-		assertNotNull(message);
-		assertEquals("foo", message.getPayload());
+		assertThat(message).isNotNull();
+		assertThat(message.getPayload()).isEqualTo("foo");
 	}
 
 	@Test
@@ -172,8 +171,8 @@ public class PublisherAnnotationAdvisorTests {
 		TestBean proxy = (TestBean) pf.getProxy();
 		proxy.test();
 		Message<?> message = testMetaChannel.receive(0);
-		assertNotNull(message);
-		assertEquals("foo", message.getPayload());
+		assertThat(message).isNotNull();
+		assertThat(message.getPayload()).isEqualTo("foo");
 	}
 
 	@Test
@@ -186,8 +185,8 @@ public class PublisherAnnotationAdvisorTests {
 		TestBean proxy = (TestBean) pf.getProxy();
 		proxy.test();
 		Message<?> message = testMetaChannel.receive(0);
-		assertNotNull(message);
-		assertEquals("foo", message.getPayload());
+		assertThat(message).isNotNull();
+		assertThat(message.getPayload()).isEqualTo("foo");
 	}
 
 	interface TestBean {

spring-integration-core/src/test/java/org/springframework/integration/aop/PublisherExpressionTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2018 the original author or authors.
+ * Copyright 2002-2019 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -16,8 +16,7 @@
 
 package org.springframework.integration.aop;
 
-import static org.junit.Assert.assertEquals;
-import static org.junit.Assert.assertNotNull;
+import static org.assertj.core.api.Assertions.assertThat;
 
 import org.junit.After;
 import org.junit.Before;
@@ -74,9 +73,9 @@ public class PublisherExpressionTests {
 		TestBean proxy = (TestBean) pf.getProxy();
 		proxy.test("123");
 		Message<?> message = testChannel.receive(0);
-		assertNotNull(message);
-		assertEquals("hellofoo", message.getPayload());
-		assertEquals("123", message.getHeaders().get("foo"));
+		assertThat(message).isNotNull();
+		assertThat(message.getPayload()).isEqualTo("hellofoo");
+		assertThat(message.getHeaders().get("foo")).isEqualTo("123");
 	}
 
 

spring-integration-core/src/test/java/org/springframework/integration/bus/ApplicationContextMessageBusTests.java

@@ -16,10 +16,7 @@
 
 package org.springframework.integration.bus;
 
-import static org.junit.Assert.assertEquals;
-import static org.junit.Assert.assertNotNull;
-import static org.junit.Assert.assertNull;
-import static org.junit.Assert.assertTrue;
+import static org.assertj.core.api.Assertions.assertThat;
 import static org.mockito.Mockito.mock;
 
 import java.util.concurrent.CountDownLatch;
@@ -78,7 +75,7 @@ public class ApplicationContextMessageBusTests {
 		context.registerEndpoint("testEndpoint", endpoint);
 		context.refresh();
 		Message<?> result = targetChannel.receive(10000);
-		assertEquals("test", result.getPayload());
+		assertThat(result.getPayload()).isEqualTo("test");
 		context.close();
 	}
 
@@ -92,7 +89,7 @@ public class ApplicationContextMessageBusTests {
 		context.registerChannel("targetChannel", targetChannel);
 		context.refresh();
 		Message<?> result = targetChannel.receive(10);
-		assertNull(result);
+		assertThat(result).isNull();
 		context.close();
 	}
 
@@ -105,7 +102,7 @@ public class ApplicationContextMessageBusTests {
 		sourceChannel.send(new GenericMessage<>("test"));
 		PollableChannel targetChannel = (PollableChannel) context.getBean("targetChannel");
 		Message<?> result = targetChannel.receive(10000);
-		assertEquals("test", result.getPayload());
+		assertThat(result.getPayload()).isEqualTo("test");
 		context.close();
 	}
 
@@ -145,7 +142,7 @@ public class ApplicationContextMessageBusTests {
 		Message<?> message1 = outputChannel1.receive(10000);
 		Message<?> message2 = outputChannel2.receive(0);
 		context.close();
-		assertTrue("exactly one message should be null", message1 == null ^ message2 == null);
+		assertThat(message1 == null ^ message2 == null).as("exactly one message should be null").isTrue();
 	}
 
 	@Test
@@ -183,12 +180,12 @@ public class ApplicationContextMessageBusTests {
 		context.refresh();
 		inputChannel.send(new GenericMessage<String>("testing"));
 		latch.await(500, TimeUnit.MILLISECONDS);
-		assertEquals("both handlers should have been invoked", 0, latch.getCount());
+		assertThat(latch.getCount()).as("both handlers should have been invoked").isEqualTo(0);
 		Message<?> message1 = outputChannel1.receive(500);
 		Message<?> message2 = outputChannel2.receive(500);
 		context.close();
-		assertNotNull("both handlers should have replied to the message", message1);
-		assertNotNull("both handlers should have replied to the message", message2);
+		assertThat(message1).as("both handlers should have replied to the message").isNotNull();
+		assertThat(message2).as("both handlers should have replied to the message").isNotNull();
 	}
 
 	@Test
@@ -208,11 +205,11 @@ public class ApplicationContextMessageBusTests {
 		latch.await(2000, TimeUnit.MILLISECONDS);
 		Message<?> message = errorChannel.receive(5000);
 		context.close();
-		assertNull(outputChannel.receive(100));
-		assertNotNull("message should not be null", message);
-		assertTrue(message instanceof ErrorMessage);
+		assertThat(outputChannel.receive(100)).isNull();
+		assertThat(message).as("message should not be null").isNotNull();
+		assertThat(message instanceof ErrorMessage).isTrue();
 		Throwable exception = ((ErrorMessage) message).getPayload();
-		assertEquals("intentional test failure", exception.getCause().getMessage());
+		assertThat(exception.getCause().getMessage()).isEqualTo("intentional test failure");
 	}
 
 	@Test
@@ -235,7 +232,7 @@ public class ApplicationContextMessageBusTests {
 		context.refresh();
 		errorChannel.send(new ErrorMessage(new RuntimeException("test-exception")));
 		latch.await(1000, TimeUnit.MILLISECONDS);
-		assertEquals("handler should have received error message", 0, latch.getCount());
+		assertThat(latch.getCount()).as("handler should have received error message").isEqualTo(0);
 		context.close();
 	}
 

spring-integration-core/src/test/java/org/springframework/integration/bus/DirectChannelSubscriptionTests.java

@@ -16,7 +16,7 @@
 
 package org.springframework.integration.bus;
 
-import static org.junit.Assert.assertEquals;
+import static org.assertj.core.api.Assertions.assertThat;
 
 import org.junit.After;
 import org.junit.Before;
@@ -73,7 +73,7 @@ public class DirectChannelSubscriptionTests {
 		context.refresh();
 		this.sourceChannel.send(new GenericMessage<>("foo"));
 		Message<?> response = this.targetChannel.receive();
-		assertEquals("foo!", response.getPayload());
+		assertThat(response.getPayload()).isEqualTo("foo!");
 	}
 
 	@Test
@@ -86,7 +86,7 @@ public class DirectChannelSubscriptionTests {
 		this.context.refresh();
 		this.sourceChannel.send(new GenericMessage<>("foo"));
 		Message<?> response = this.targetChannel.receive();
-		assertEquals("foo-from-annotated-endpoint", response.getPayload());
+		assertThat(response.getPayload()).isEqualTo("foo-from-annotated-endpoint");
 	}
 
 	@Test(expected = MessagingException.class)

spring-integration-core/src/test/java/org/springframework/integration/channel/CGLibProxyChannelTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2017-2018 the original author or authors.
+ * Copyright 2017-2019 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -16,8 +16,7 @@
 
 package org.springframework.integration.channel;
 
-import static org.junit.Assert.assertNotNull;
-import static org.junit.Assert.assertTrue;
+import static org.assertj.core.api.Assertions.assertThat;
 
 import java.util.concurrent.CountDownLatch;
 import java.util.concurrent.Executor;
@@ -61,23 +60,23 @@ public class CGLibProxyChannelTests {
 
 	@Test
 	public void testProxyDirect() {
-		assertTrue(AopUtils.isCglibProxy(this.directChannel));
+		assertThat(AopUtils.isCglibProxy(this.directChannel)).isTrue();
 		final AtomicReference<Message<?>> message = new AtomicReference<>();
 		this.directChannel.subscribe(m -> message.set(m));
 		this.directChannel.send(new GenericMessage<>("foo"));
-		assertNotNull(message.get());
+		assertThat(message.get()).isNotNull();
 	}
 
 	@Test
 	public void testProxyQueue() {
-		assertTrue(AopUtils.isCglibProxy(this.queueChannel));
+		assertThat(AopUtils.isCglibProxy(this.queueChannel)).isTrue();
 		this.queueChannel.send(new GenericMessage<>("foo"));
-		assertNotNull(this.queueChannel.receive(0));
+		assertThat(this.queueChannel.receive(0)).isNotNull();
 	}
 
 	@Test
 	public void testProxyExecutor() throws Exception {
-		assertTrue(AopUtils.isCglibProxy(this.executorChannel));
+		assertThat(AopUtils.isCglibProxy(this.executorChannel)).isTrue();
 		final AtomicReference<Message<?>> message = new AtomicReference<>();
 		final CountDownLatch latch = new CountDownLatch(1);
 		this.executorChannel.subscribe(m -> {
@@ -85,13 +84,13 @@ public class CGLibProxyChannelTests {
 			latch.countDown();
 		});
 		this.executorChannel.send(new GenericMessage<>("foo"));
-		assertTrue(latch.await(10, TimeUnit.SECONDS));
-		assertNotNull(message.get());
+		assertThat(latch.await(10, TimeUnit.SECONDS)).isTrue();
+		assertThat(message.get()).isNotNull();
 	}
 
 	@Test
 	public void testProxyPubSubWithExec() throws Exception {
-		assertTrue(AopUtils.isCglibProxy(this.publishSubscribeChannel));
+		assertThat(AopUtils.isCglibProxy(this.publishSubscribeChannel)).isTrue();
 		final AtomicReference<Message<?>> message = new AtomicReference<>();
 		final CountDownLatch latch = new CountDownLatch(1);
 		this.publishSubscribeChannel.subscribe(m -> {
@@ -99,8 +98,8 @@ public class CGLibProxyChannelTests {
 			latch.countDown();
 		});
 		this.publishSubscribeChannel.send(new GenericMessage<>("foo"));
-		assertTrue(latch.await(10, TimeUnit.SECONDS));
-		assertNotNull(message.get());
+		assertThat(latch.await(10, TimeUnit.SECONDS)).isTrue();
+		assertThat(message.get()).isNotNull();
 	}
 
 	@Configuration

spring-integration-core/src/test/java/org/springframework/integration/channel/ChannelPurgerTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2016 the original author or authors.
+ * Copyright 2002-2019 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -16,9 +16,7 @@
 
 package org.springframework.integration.channel;
 
-import static org.junit.Assert.assertEquals;
-import static org.junit.Assert.assertNotNull;
-import static org.junit.Assert.assertNull;
+import static org.assertj.core.api.Assertions.assertThat;
 
 import java.util.List;
 
@@ -40,8 +38,8 @@ public class ChannelPurgerTests {
 		channel.send(new GenericMessage<String>("test3"));
 		ChannelPurger purger = new ChannelPurger(channel);
 		List<Message<?>> purgedMessages = purger.purge();
-		assertEquals(3, purgedMessages.size());
-		assertNull(channel.receive(0));
+		assertThat(purgedMessages.size()).isEqualTo(3);
+		assertThat(channel.receive(0)).isNull();
 	}
 
 	@Test
@@ -52,8 +50,8 @@ public class ChannelPurgerTests {
 		channel.send(new GenericMessage<String>("test3"));
 		ChannelPurger purger = new ChannelPurger(message -> false, channel);
 		List<Message<?>> purgedMessages = purger.purge();
-		assertEquals(3, purgedMessages.size());
-		assertNull(channel.receive(0));
+		assertThat(purgedMessages.size()).isEqualTo(3);
+		assertThat(channel.receive(0)).isNull();
 	}
 
 	@Test
@@ -64,10 +62,10 @@ public class ChannelPurgerTests {
 		channel.send(new GenericMessage<String>("test3"));
 		ChannelPurger purger = new ChannelPurger(message -> true, channel);
 		List<Message<?>> purgedMessages = purger.purge();
-		assertEquals(0, purgedMessages.size());
-		assertNotNull(channel.receive(0));
-		assertNotNull(channel.receive(0));
-		assertNotNull(channel.receive(0));
+		assertThat(purgedMessages.size()).isEqualTo(0);
+		assertThat(channel.receive(0)).isNotNull();
+		assertThat(channel.receive(0)).isNotNull();
+		assertThat(channel.receive(0)).isNotNull();
 	}
 
 	@Test
@@ -78,11 +76,11 @@ public class ChannelPurgerTests {
 		channel.send(new GenericMessage<String>("test3"));
 		ChannelPurger purger = new ChannelPurger(message -> (message.getPayload().equals("test2")), channel);
 		List<Message<?>> purgedMessages = purger.purge();
-		assertEquals(2, purgedMessages.size());
+		assertThat(purgedMessages.size()).isEqualTo(2);
 		Message<?> message = channel.receive(0);
-		assertNotNull(message);
-		assertEquals("test2", message.getPayload());
-		assertNull(channel.receive(0));
+		assertThat(message).isNotNull();
+		assertThat(message.getPayload()).isEqualTo("test2");
+		assertThat(channel.receive(0)).isNull();
 	}
 
 	@Test
@@ -95,9 +93,9 @@ public class ChannelPurgerTests {
 		channel2.send(new GenericMessage<String>("test2"));
 		ChannelPurger purger = new ChannelPurger(channel1, channel2);
 		List<Message<?>> purgedMessages = purger.purge();
-		assertEquals(4, purgedMessages.size());
-		assertNull(channel1.receive(0));
-		assertNull(channel2.receive(0));
+		assertThat(purgedMessages.size()).isEqualTo(4);
+		assertThat(channel1.receive(0)).isNull();
+		assertThat(channel2.receive(0)).isNull();
 	}
 
 	@Test
@@ -112,15 +110,15 @@ public class ChannelPurgerTests {
 		channel2.send(new GenericMessage<String>("test3"));
 		ChannelPurger purger = new ChannelPurger(message -> (message.getPayload().equals("test2")), channel1, channel2);
 		List<Message<?>> purgedMessages = purger.purge();
-		assertEquals(4, purgedMessages.size());
+		assertThat(purgedMessages.size()).isEqualTo(4);
 		Message<?> message1 = channel1.receive(0);
-		assertNotNull(message1);
-		assertEquals("test2", message1.getPayload());
-		assertNull(channel1.receive(0));
+		assertThat(message1).isNotNull();
+		assertThat(message1.getPayload()).isEqualTo("test2");
+		assertThat(channel1.receive(0)).isNull();
 		Message<?> message2 = channel2.receive(0);
-		assertNotNull(message2);
-		assertEquals("test2", message2.getPayload());
-		assertNull(channel2.receive(0));
+		assertThat(message2).isNotNull();
+		assertThat(message2.getPayload()).isEqualTo("test2");
+		assertThat(channel2.receive(0)).isNull();
 	}
 
 	@Test
@@ -133,11 +131,11 @@ public class ChannelPurgerTests {
 		channel2.send(new GenericMessage<String>("test2"));
 		ChannelPurger purger = new ChannelPurger(message -> true, channel1, channel2);
 		List<Message<?>> purgedMessages = purger.purge();
-		assertEquals(0, purgedMessages.size());
-		assertNotNull(channel1.receive(0));
-		assertNotNull(channel1.receive(0));
-		assertNotNull(channel2.receive(0));
-		assertNotNull(channel2.receive(0));
+		assertThat(purgedMessages.size()).isEqualTo(0);
+		assertThat(channel1.receive(0)).isNotNull();
+		assertThat(channel1.receive(0)).isNotNull();
+		assertThat(channel2.receive(0)).isNotNull();
+		assertThat(channel2.receive(0)).isNotNull();
 	}
 
 	@Test(expected = IllegalArgumentException.class)

spring-integration-core/src/test/java/org/springframework/integration/channel/DatatypeChannelTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2014 the original author or authors.
+ * Copyright 2002-2019 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -16,12 +16,7 @@
 
 package org.springframework.integration.channel;
 
-import static org.hamcrest.Matchers.instanceOf;
-import static org.junit.Assert.assertEquals;
-import static org.junit.Assert.assertNotNull;
-import static org.junit.Assert.assertSame;
-import static org.junit.Assert.assertThat;
-import static org.junit.Assert.assertTrue;
+import static org.assertj.core.api.Assertions.assertThat;
 
 import java.util.Collections;
 import java.util.Date;
@@ -63,7 +58,7 @@ public class DatatypeChannelTests {
 	@Test
 	public void supportedType() {
 		MessageChannel channel = createChannel(String.class);
-		assertTrue(channel.send(new GenericMessage<String>("test")));
+		assertThat(channel.send(new GenericMessage<String>("test"))).isTrue();
 	}
 
 	@Test(expected = MessageDeliveryException.class)
@@ -79,7 +74,7 @@ public class DatatypeChannelTests {
 		DefaultDatatypeChannelMessageConverter converter = new DefaultDatatypeChannelMessageConverter();
 		converter.setConversionService(conversionService);
 		channel.setMessageConverter(converter);
-		assertTrue(channel.send(new GenericMessage<String>("123")));
+		assertThat(channel.send(new GenericMessage<String>("123"))).isTrue();
 	}
 
 	@Test(expected = MessageDeliveryException.class)
@@ -89,7 +84,7 @@ public class DatatypeChannelTests {
 		DefaultDatatypeChannelMessageConverter converter = new DefaultDatatypeChannelMessageConverter();
 		converter.setConversionService(conversionService);
 		channel.setMessageConverter(converter);
-		assertTrue(channel.send(new GenericMessage<Boolean>(Boolean.TRUE)));
+		assertThat(channel.send(new GenericMessage<Boolean>(Boolean.TRUE))).isTrue();
 	}
 
 	@Test
@@ -105,8 +100,8 @@ public class DatatypeChannelTests {
 		DefaultDatatypeChannelMessageConverter converter = new DefaultDatatypeChannelMessageConverter();
 		converter.setConversionService(conversionService);
 		channel.setMessageConverter(converter);
-		assertTrue(channel.send(new GenericMessage<Boolean>(Boolean.TRUE)));
-		assertEquals(1, channel.receive().getPayload());
+		assertThat(channel.send(new GenericMessage<Boolean>(Boolean.TRUE))).isTrue();
+		assertThat(channel.receive().getPayload()).isEqualTo(1);
 	}
 
 	@Test
@@ -135,10 +130,10 @@ public class DatatypeChannelTests {
 		context.refresh();
 
 		QueueChannel channel = context.getBean("testChannel", QueueChannel.class);
-		assertSame(context.getBean(ConversionService.class),
-				TestUtils.getPropertyValue(channel, "messageConverter.conversionService"));
-		assertTrue(channel.send(new GenericMessage<Boolean>(Boolean.TRUE)));
-		assertEquals(1, channel.receive().getPayload());
+		assertThat(TestUtils.getPropertyValue(channel, "messageConverter.conversionService"))
+				.isSameAs(context.getBean(ConversionService.class));
+		assertThat(channel.send(new GenericMessage<Boolean>(Boolean.TRUE))).isTrue();
+		assertThat(channel.receive().getPayload()).isEqualTo(1);
 		context.close();
 	}
 
@@ -174,16 +169,16 @@ public class DatatypeChannelTests {
 		context.refresh();
 
 		QueueChannel channel = context.getBean("testChannel", QueueChannel.class);
-		assertTrue(channel.send(new GenericMessage<Boolean>(Boolean.TRUE)));
-		assertEquals(99, channel.receive().getPayload());
+		assertThat(channel.send(new GenericMessage<Boolean>(Boolean.TRUE))).isTrue();
+		assertThat(channel.receive().getPayload()).isEqualTo(99);
 		context.close();
 	}
 
 	@Test
 	public void multipleTypes() {
 		MessageChannel channel = createChannel(String.class, Integer.class);
-		assertTrue(channel.send(new GenericMessage<String>("test1")));
-		assertTrue(channel.send(new GenericMessage<Integer>(2)));
+		assertThat(channel.send(new GenericMessage<String>("test1"))).isTrue();
+		assertThat(channel.send(new GenericMessage<Integer>(2))).isTrue();
 		Exception exception = null;
 		try {
 			channel.send(new GenericMessage<Date>(new Date()));
@@ -191,13 +186,13 @@ public class DatatypeChannelTests {
 		catch (MessageDeliveryException e) {
 			exception = e;
 		}
-		assertNotNull(exception);
+		assertThat(exception).isNotNull();
 	}
 
 	@Test
 	public void subclassOfAcceptedType() {
 		MessageChannel channel = createChannel(RuntimeException.class);
-		assertTrue(channel.send(new ErrorMessage(new MessagingException("test"))));
+		assertThat(channel.send(new ErrorMessage(new MessagingException("test")))).isTrue();
 	}
 
 	@Test(expected = MessageDeliveryException.class)
@@ -215,12 +210,12 @@ public class DatatypeChannelTests {
 		DefaultDatatypeChannelMessageConverter converter = new DefaultDatatypeChannelMessageConverter();
 		converter.setConversionService(conversionService);
 		channel.setMessageConverter(converter);
-		assertTrue(channel.send(new GenericMessage<String>("foo")));
+		assertThat(channel.send(new GenericMessage<String>("foo"))).isTrue();
 		Message<?> out = channel.receive(0);
-		assertThat(out.getPayload(), instanceOf(Bar.class));
-		assertTrue(channel.send(new GenericMessage<Integer>(42)));
+		assertThat(out.getPayload()).isInstanceOf(Bar.class);
+		assertThat(channel.send(new GenericMessage<Integer>(42))).isTrue();
 		out = channel.receive(0);
-		assertThat(out.getPayload(), instanceOf(Baz.class));
+		assertThat(out.getPayload()).isInstanceOf(Baz.class);
 	}
 
 

spring-integration-core/src/test/java/org/springframework/integration/channel/DirectChannelParserTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2016 the original author or authors.
+ * Copyright 2002-2019 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -16,8 +16,7 @@
 
 package org.springframework.integration.channel;
 
-import static org.junit.Assert.assertEquals;
-import static org.junit.Assert.assertTrue;
+import static org.assertj.core.api.Assertions.assertThat;
 
 import org.junit.Test;
 
@@ -37,9 +36,10 @@ public class DirectChannelParserTests {
 		ClassPathXmlApplicationContext context = new ClassPathXmlApplicationContext(
 				"directChannelParserTests.xml", DirectChannelParserTests.class);
 		Object channel = context.getBean("channel");
-		assertEquals(DirectChannel.class, channel.getClass());
+		assertThat(channel.getClass()).isEqualTo(DirectChannel.class);
 		DirectFieldAccessor dcAccessor = new DirectFieldAccessor(((DirectChannel) channel).getDispatcher());
-		assertTrue(dcAccessor.getPropertyValue("loadBalancingStrategy") instanceof RoundRobinLoadBalancingStrategy);
+		assertThat(dcAccessor.getPropertyValue("loadBalancingStrategy") instanceof RoundRobinLoadBalancingStrategy)
+				.isTrue();
 		context.close();
 	}
 

spring-integration-core/src/test/java/org/springframework/integration/channel/DirectChannelTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2015 the original author or authors.
+ * Copyright 2002-2019 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -16,11 +16,7 @@
 
 package org.springframework.integration.channel;
 
-import static org.hamcrest.Matchers.startsWith;
-import static org.junit.Assert.assertEquals;
-import static org.junit.Assert.assertFalse;
-import static org.junit.Assert.assertThat;
-import static org.junit.Assert.assertTrue;
+import static org.assertj.core.api.Assertions.assertThat;
 import static org.mockito.Mockito.spy;
 import static org.mockito.Mockito.times;
 import static org.mockito.Mockito.verify;
@@ -64,19 +60,19 @@ public class DirectChannelTests {
 		ThreadNameExtractingTestTarget target = new ThreadNameExtractingTestTarget();
 		channel.subscribe(target);
 		GenericMessage<String> message = new GenericMessage<String>("test");
-		assertTrue(channel.send(message));
-		assertEquals(Thread.currentThread().getName(), target.threadName);
+		assertThat(channel.send(message)).isTrue();
+		assertThat(target.threadName).isEqualTo(Thread.currentThread().getName());
 		DirectFieldAccessor channelAccessor = new DirectFieldAccessor(channel);
 		UnicastingDispatcher dispatcher = (UnicastingDispatcher) channelAccessor.getPropertyValue("dispatcher");
 		DirectFieldAccessor dispatcherAccessor = new DirectFieldAccessor(dispatcher);
 		Object loadBalancingStrategy = dispatcherAccessor.getPropertyValue("loadBalancingStrategy");
-		assertTrue(loadBalancingStrategy instanceof RoundRobinLoadBalancingStrategy);
+		assertThat(loadBalancingStrategy instanceof RoundRobinLoadBalancingStrategy).isTrue();
 		ArgumentCaptor<String> captor = ArgumentCaptor.forClass(String.class);
 		verify(logger, times(2)).debug(captor.capture());
 		List<String> logs = captor.getAllValues();
-		assertEquals(2, logs.size());
-		assertThat(logs.get(0), startsWith("preSend"));
-		assertThat(logs.get(1), startsWith("postSend"));
+		assertThat(logs.size()).isEqualTo(2);
+		assertThat(logs.get(0)).startsWith("preSend");
+		assertThat(logs.get(1)).startsWith("postSend");
 	}
 
 	@Test
@@ -94,7 +90,7 @@ public class DirectChannelTests {
 		final AtomicInteger count = new AtomicInteger();
 		channel.subscribe(message -> count.incrementAndGet());
 		GenericMessage<String> message = new GenericMessage<String>("test");
-		assertTrue(channel.send(message));
+		assertThat(channel.send(message)).isTrue();
 		for (int i = 0; i < 10000000; i++) {
 			channel.send(message);
 		}
@@ -115,12 +111,12 @@ public class DirectChannelTests {
 		channel.subscribe(message -> count1.incrementAndGet());
 		channel.subscribe(message -> count2.getAndIncrement());
 		GenericMessage<String> message = new GenericMessage<String>("test");
-		assertTrue(channel.send(message));
+		assertThat(channel.send(message)).isTrue();
 		for (int i = 0; i < 10000000; i++) {
 			channel.send(message);
 		}
-		assertEquals(5000001, count1.get());
-		assertEquals(5000000, count2.get());
+		assertThat(count1.get()).isEqualTo(5000001);
+		assertThat(count2.get()).isEqualTo(5000000);
 	}
 
 	@Test
@@ -135,7 +131,7 @@ public class DirectChannelTests {
 		final AtomicInteger count = new AtomicInteger();
 		FixedSubscriberChannel channel = new FixedSubscriberChannel(message -> count.incrementAndGet());
 		GenericMessage<String> message = new GenericMessage<String>("test");
-		assertTrue(channel.send(message));
+		assertThat(channel.send(message)).isTrue();
 		for (int i = 0; i < 100000000; i++) {
 			channel.send(message, 0);
 		}
@@ -150,7 +146,7 @@ public class DirectChannelTests {
 		final GenericMessage<String> message = new GenericMessage<String>("test");
 		new Thread((Runnable) () -> channel.send(message), "test-thread").start();
 		latch.await(1000, TimeUnit.MILLISECONDS);
-		assertEquals("test-thread", target.threadName);
+		assertThat(target.threadName).isEqualTo("test-thread");
 	}
 
 	@Test //  See INT-2434
@@ -166,40 +162,43 @@ public class DirectChannelTests {
 		Method method = ReflectionUtils.findMethod(ClassPathXmlApplicationContext.class, "obtainFreshBeanFactory");
 		method.setAccessible(true);
 		method.invoke(context);
-		assertFalse(context.containsBean("channelA"));
-		assertFalse(context.containsBean("channelB"));
-		assertTrue(context.containsBean("channelC"));
-		assertTrue(context.containsBean("channelD"));
+		assertThat(context.containsBean("channelA")).isFalse();
+		assertThat(context.containsBean("channelB")).isFalse();
+		assertThat(context.containsBean("channelC")).isTrue();
+		assertThat(context.containsBean("channelD")).isTrue();
 
 		context.refresh();
 
 		PublishSubscribeChannel channelEarly = context.getBean("channelEarly", PublishSubscribeChannel.class);
 
-		assertTrue(context.containsBean("channelA"));
-		assertTrue(context.containsBean("channelB"));
-		assertTrue(context.containsBean("channelC"));
-		assertTrue(context.containsBean("channelD"));
+		assertThat(context.containsBean("channelA")).isTrue();
+		assertThat(context.containsBean("channelB")).isTrue();
+		assertThat(context.containsBean("channelC")).isTrue();
+		assertThat(context.containsBean("channelD")).isTrue();
 		EventDrivenConsumer consumerA = context.getBean("serviceA", EventDrivenConsumer.class);
-		assertEquals(context.getBean("channelA"), TestUtils.getPropertyValue(consumerA, "inputChannel"));
-		assertEquals(context.getBean("channelB"), TestUtils.getPropertyValue(consumerA, "handler.outputChannel"));
+		assertThat(TestUtils.getPropertyValue(consumerA, "inputChannel")).isEqualTo(context.getBean("channelA"));
+		assertThat(TestUtils.getPropertyValue(consumerA, "handler.outputChannel"))
+				.isEqualTo(context.getBean("channelB"));
 
 		EventDrivenConsumer consumerB = context.getBean("serviceB", EventDrivenConsumer.class);
-		assertEquals(context.getBean("channelB"), TestUtils.getPropertyValue(consumerB, "inputChannel"));
-		assertEquals(context.getBean("channelC"), TestUtils.getPropertyValue(consumerB, "handler.outputChannel"));
+		assertThat(TestUtils.getPropertyValue(consumerB, "inputChannel")).isEqualTo(context.getBean("channelB"));
+		assertThat(TestUtils.getPropertyValue(consumerB, "handler.outputChannel"))
+				.isEqualTo(context.getBean("channelC"));
 
 		EventDrivenConsumer consumerC = context.getBean("serviceC", EventDrivenConsumer.class);
-		assertEquals(context.getBean("channelC"), TestUtils.getPropertyValue(consumerC, "inputChannel"));
-		assertEquals(context.getBean("channelD"), TestUtils.getPropertyValue(consumerC, "handler.outputChannel"));
+		assertThat(TestUtils.getPropertyValue(consumerC, "inputChannel")).isEqualTo(context.getBean("channelC"));
+		assertThat(TestUtils.getPropertyValue(consumerC, "handler.outputChannel"))
+				.isEqualTo(context.getBean("channelD"));
 
 		EventDrivenConsumer consumerD = context.getBean("serviceD", EventDrivenConsumer.class);
-		assertEquals(parentChannelA, TestUtils.getPropertyValue(consumerD, "inputChannel"));
-		assertEquals(parentChannelB, TestUtils.getPropertyValue(consumerD, "handler.outputChannel"));
+		assertThat(TestUtils.getPropertyValue(consumerD, "inputChannel")).isEqualTo(parentChannelA);
+		assertThat(TestUtils.getPropertyValue(consumerD, "handler.outputChannel")).isEqualTo(parentChannelB);
 
 		EventDrivenConsumer consumerE = context.getBean("serviceE", EventDrivenConsumer.class);
-		assertEquals(parentChannelB, TestUtils.getPropertyValue(consumerE, "inputChannel"));
+		assertThat(TestUtils.getPropertyValue(consumerE, "inputChannel")).isEqualTo(parentChannelB);
 
 		EventDrivenConsumer consumerF = context.getBean("serviceF", EventDrivenConsumer.class);
-		assertEquals(channelEarly, TestUtils.getPropertyValue(consumerF, "inputChannel"));
+		assertThat(TestUtils.getPropertyValue(consumerF, "inputChannel")).isEqualTo(channelEarly);
 	}
 
 

spring-integration-core/src/test/java/org/springframework/integration/channel/DispatcherHasNoSubscribersTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2014 the original author or authors.
+ * Copyright 2002-2019 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -16,9 +16,8 @@
 
 package org.springframework.integration.channel;
 
-import static org.hamcrest.Matchers.containsString;
-import static org.junit.Assert.assertThat;
-import static org.junit.Assert.fail;
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.assertj.core.api.Assertions.fail;
 
 import org.junit.Before;
 import org.junit.Test;
@@ -63,8 +62,8 @@ public class DispatcherHasNoSubscribersTests {
 			fail("Exception expected");
 		}
 		catch (MessagingException e) {
-			assertThat(e.getMessage(),
-					containsString("Dispatcher has no subscribers for channel 'foo.noSubscribersChannel'."));
+			assertThat(e.getMessage())
+					.contains("Dispatcher has no subscribers for channel 'foo.noSubscribersChannel'.");
 		}
 	}
 
@@ -75,8 +74,8 @@ public class DispatcherHasNoSubscribersTests {
 			fail("Exception expected");
 		}
 		catch (MessagingException e) {
-			assertThat(e.getMessage(),
-					containsString("Dispatcher has no subscribers for channel 'foo.noSubscribersChannel'."));
+			assertThat(e.getMessage())
+					.contains("Dispatcher has no subscribers for channel 'foo.noSubscribersChannel'.");
 		}
 	}
 
@@ -89,8 +88,7 @@ public class DispatcherHasNoSubscribersTests {
 			fail("Exception expected");
 		}
 		catch (MessagingException e) {
-			assertThat(e.getMessage(),
-					containsString("Dispatcher has no subscribers for channel 'bar'."));
+			assertThat(e.getMessage()).contains("Dispatcher has no subscribers for channel 'bar'.");
 		}
 	}
 

spring-integration-core/src/test/java/org/springframework/integration/channel/DispatchingChannelErrorHandlingTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2016 the original author or authors.
+ * Copyright 2002-2019 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -16,9 +16,7 @@
 
 package org.springframework.integration.channel;
 
-import static org.junit.Assert.assertEquals;
-import static org.junit.Assert.assertNotSame;
-import static org.junit.Assert.assertSame;
+import static org.assertj.core.api.Assertions.assertThat;
 
 import java.util.concurrent.CountDownLatch;
 import java.util.concurrent.TimeUnit;
@@ -76,11 +74,11 @@ public class DispatchingChannelErrorHandlingTests {
 		channel.send(message);
 		this.waitForLatch(10000);
 		Message<?> errorMessage = resultHandler.lastMessage;
-		assertEquals(MessagingException.class, errorMessage.getPayload().getClass());
+		assertThat(errorMessage.getPayload().getClass()).isEqualTo(MessagingException.class);
 		MessagingException exceptionPayload = (MessagingException) errorMessage.getPayload();
-		assertEquals(UnsupportedOperationException.class, exceptionPayload.getCause().getClass());
-		assertSame(message, exceptionPayload.getFailedMessage());
-		assertNotSame(Thread.currentThread(), resultHandler.lastThread);
+		assertThat(exceptionPayload.getCause().getClass()).isEqualTo(UnsupportedOperationException.class);
+		assertThat(exceptionPayload.getFailedMessage()).isSameAs(message);
+		assertThat(resultHandler.lastThread).isNotSameAs(Thread.currentThread());
 	}
 
 	@Test
@@ -105,11 +103,11 @@ public class DispatchingChannelErrorHandlingTests {
 		channel.send(message);
 		this.waitForLatch(10000);
 		Message<?> errorMessage = resultHandler.lastMessage;
-		assertEquals(MessagingException.class, errorMessage.getPayload().getClass());
+		assertThat(errorMessage.getPayload().getClass()).isEqualTo(MessagingException.class);
 		MessagingException exceptionPayload = (MessagingException) errorMessage.getPayload();
-		assertEquals(UnsupportedOperationException.class, exceptionPayload.getCause().getClass());
-		assertSame(message, exceptionPayload.getFailedMessage());
-		assertNotSame(Thread.currentThread(), resultHandler.lastThread);
+		assertThat(exceptionPayload.getCause().getClass()).isEqualTo(UnsupportedOperationException.class);
+		assertThat(exceptionPayload.getFailedMessage()).isSameAs(message);
+		assertThat(resultHandler.lastThread).isNotSameAs(Thread.currentThread());
 	}
 
 

spring-integration-core/src/test/java/org/springframework/integration/channel/ExecutorChannelTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2018 the original author or authors.
+ * Copyright 2002-2019 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -16,15 +16,8 @@
 
 package org.springframework.integration.channel;
 
-import static org.hamcrest.Matchers.equalTo;
-import static org.junit.Assert.assertEquals;
-import static org.junit.Assert.assertFalse;
-import static org.junit.Assert.assertNotNull;
-import static org.junit.Assert.assertNull;
-import static org.junit.Assert.assertSame;
-import static org.junit.Assert.assertThat;
-import static org.junit.Assert.assertTrue;
-import static org.junit.Assert.fail;
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.assertj.core.api.Assertions.fail;
 import static org.mockito.BDDMockito.willThrow;
 import static org.mockito.Mockito.mock;
 import static org.mockito.Mockito.verify;
@@ -65,12 +58,12 @@ public class ExecutorChannelTests {
 		CountDownLatch latch = new CountDownLatch(1);
 		TestHandler handler = new TestHandler(latch);
 		channel.subscribe(handler);
-		channel.send(new GenericMessage<String>("test"));
+		channel.send(new GenericMessage<>("test"));
 		latch.await(1000, TimeUnit.MILLISECONDS);
-		assertEquals(0, latch.getCount());
-		assertNotNull(handler.thread);
-		assertFalse(Thread.currentThread().equals(handler.thread));
-		assertEquals("test-1", handler.thread.getName());
+		assertThat(latch.getCount()).isEqualTo(0);
+		assertThat(handler.thread).isNotNull();
+		assertThat(Thread.currentThread().equals(handler.thread)).isFalse();
+		assertThat(handler.thread.getName()).isEqualTo("test-1");
 	}
 
 	@Test
@@ -89,22 +82,22 @@ public class ExecutorChannelTests {
 		channel.subscribe(handler2);
 		channel.subscribe(handler3);
 		for (int i = 0; i < numberOfMessages; i++) {
-			channel.send(new GenericMessage<String>("test-" + i));
+			channel.send(new GenericMessage<>("test-" + i));
 		}
 		latch.await(3000, TimeUnit.MILLISECONDS);
-		assertEquals(0, latch.getCount());
-		assertNotNull(handler1.thread);
-		assertFalse(Thread.currentThread().equals(handler1.thread));
-		assertTrue(handler1.thread.getName().startsWith("test-"));
-		assertNotNull(handler2.thread);
-		assertFalse(Thread.currentThread().equals(handler2.thread));
-		assertTrue(handler2.thread.getName().startsWith("test-"));
-		assertNotNull(handler3.thread);
-		assertFalse(Thread.currentThread().equals(handler3.thread));
-		assertTrue(handler3.thread.getName().startsWith("test-"));
-		assertEquals(4, handler1.count.get());
-		assertEquals(4, handler2.count.get());
-		assertEquals(3, handler3.count.get());
+		assertThat(latch.getCount()).isEqualTo(0);
+		assertThat(handler1.thread).isNotNull();
+		assertThat(Thread.currentThread().equals(handler1.thread)).isFalse();
+		assertThat(handler1.thread.getName().startsWith("test-")).isTrue();
+		assertThat(handler2.thread).isNotNull();
+		assertThat(Thread.currentThread().equals(handler2.thread)).isFalse();
+		assertThat(handler2.thread.getName().startsWith("test-")).isTrue();
+		assertThat(handler3.thread).isNotNull();
+		assertThat(Thread.currentThread().equals(handler3.thread)).isFalse();
+		assertThat(handler3.thread.getName().startsWith("test-")).isTrue();
+		assertThat(handler1.count.get()).isEqualTo(4);
+		assertThat(handler2.count.get()).isEqualTo(4);
+		assertThat(handler3.count.get()).isEqualTo(3);
 		exec.shutdownNow();
 	}
 
@@ -125,22 +118,22 @@ public class ExecutorChannelTests {
 		channel.subscribe(handler3);
 		handler2.shouldFail = true;
 		for (int i = 0; i < numberOfMessages; i++) {
-			channel.send(new GenericMessage<String>("test-" + i));
+			channel.send(new GenericMessage<>("test-" + i));
 		}
 		latch.await(3000, TimeUnit.MILLISECONDS);
-		assertEquals(0, latch.getCount());
-		assertNotNull(handler1.thread);
-		assertFalse(Thread.currentThread().equals(handler1.thread));
-		assertTrue(handler1.thread.getName().startsWith("test-"));
-		assertNotNull(handler2.thread);
-		assertFalse(Thread.currentThread().equals(handler2.thread));
-		assertTrue(handler2.thread.getName().startsWith("test-"));
-		assertNotNull(handler3.thread);
-		assertFalse(Thread.currentThread().equals(handler3.thread));
-		assertTrue(handler3.thread.getName().startsWith("test-"));
-		assertEquals(0, handler2.count.get());
-		assertEquals(4, handler1.count.get());
-		assertEquals(7, handler3.count.get());
+		assertThat(latch.getCount()).isEqualTo(0);
+		assertThat(handler1.thread).isNotNull();
+		assertThat(Thread.currentThread().equals(handler1.thread)).isFalse();
+		assertThat(handler1.thread.getName().startsWith("test-")).isTrue();
+		assertThat(handler2.thread).isNotNull();
+		assertThat(Thread.currentThread().equals(handler2.thread)).isFalse();
+		assertThat(handler2.thread.getName().startsWith("test-")).isTrue();
+		assertThat(handler3.thread).isNotNull();
+		assertThat(Thread.currentThread().equals(handler3.thread)).isFalse();
+		assertThat(handler3.thread.getName().startsWith("test-")).isTrue();
+		assertThat(handler2.count.get()).isEqualTo(0);
+		assertThat(handler1.count.get()).isEqualTo(4);
+		assertThat(handler3.count.get()).isEqualTo(7);
 		exec.shutdownNow();
 	}
 
@@ -160,20 +153,20 @@ public class ExecutorChannelTests {
 		channel.subscribe(handler3);
 		handler1.shouldFail = true;
 		for (int i = 0; i < numberOfMessages; i++) {
-			channel.send(new GenericMessage<String>("test-" + i));
+			channel.send(new GenericMessage<>("test-" + i));
 		}
 		latch.await(3000, TimeUnit.MILLISECONDS);
-		assertEquals(0, latch.getCount());
-		assertNotNull(handler1.thread);
-		assertFalse(Thread.currentThread().equals(handler1.thread));
-		assertTrue(handler1.thread.getName().startsWith("test-"));
-		assertNotNull(handler2.thread);
-		assertFalse(Thread.currentThread().equals(handler2.thread));
-		assertTrue(handler2.thread.getName().startsWith("test-"));
-		assertNull(handler3.thread);
-		assertEquals(0, handler1.count.get());
-		assertEquals(0, handler3.count.get());
-		assertEquals(numberOfMessages, handler2.count.get());
+		assertThat(latch.getCount()).isEqualTo(0);
+		assertThat(handler1.thread).isNotNull();
+		assertThat(Thread.currentThread().equals(handler1.thread)).isFalse();
+		assertThat(handler1.thread.getName().startsWith("test-")).isTrue();
+		assertThat(handler2.thread).isNotNull();
+		assertThat(Thread.currentThread().equals(handler2.thread)).isFalse();
+		assertThat(handler2.thread.getName().startsWith("test-")).isTrue();
+		assertThat(handler3.thread).isNull();
+		assertThat(handler1.count.get()).isEqualTo(0);
+		assertThat(handler3.count.get()).isEqualTo(0);
+		assertThat(handler2.count.get()).isEqualTo(numberOfMessages);
 		exec.shutdownNow();
 	}
 
@@ -191,8 +184,8 @@ public class ExecutorChannelTests {
 		channel.subscribe(handler);
 		channel.send(new GenericMessage<Object>("foo"));
 		verify(handler).handleMessage(expected);
-		assertEquals(1, interceptor.getCounter().get());
-		assertTrue(interceptor.wasAfterHandledInvoked());
+		assertThat(interceptor.getCounter().get()).isEqualTo(1);
+		assertThat(interceptor.wasAfterHandledInvoked()).isTrue();
 	}
 
 	@Test
@@ -201,7 +194,7 @@ public class ExecutorChannelTests {
 		channel.setBeanFactory(mock(BeanFactory.class));
 		channel.afterPropertiesSet();
 
-		Message<Object> message = new GenericMessage<Object>("foo");
+		Message<Object> message = new GenericMessage<>("foo");
 
 		MessageHandler handler = mock(MessageHandler.class);
 		IllegalStateException expected = new IllegalStateException("Fake exception");
@@ -213,25 +206,26 @@ public class ExecutorChannelTests {
 			channel.send(message);
 		}
 		catch (MessageDeliveryException actual) {
-			assertSame(expected, actual.getCause());
+			assertThat(actual.getCause()).isSameAs(expected);
 		}
 		verify(handler).handleMessage(message);
-		assertEquals(1, interceptor.getCounter().get());
-		assertTrue(interceptor.wasAfterHandledInvoked());
+		assertThat(interceptor.getCounter().get()).isEqualTo(1);
+		assertThat(interceptor.wasAfterHandledInvoked()).isTrue();
 	}
 
 	@Test
 	public void testEarlySubscribe() {
 		ExecutorChannel channel = new ExecutorChannel(mock(Executor.class));
 		try {
-			channel.subscribe(m -> { });
+			channel.subscribe(m -> {
+			});
 			channel.setBeanFactory(mock(BeanFactory.class));
 			channel.afterPropertiesSet();
 			fail("expected Exception");
 		}
 		catch (IllegalStateException e) {
-			assertThat(e.getMessage(), equalTo("You cannot subscribe() until the channel "
-					+ "bean is fully initialized by the framework. Do not subscribe in a @Bean definition"));
+			assertThat(e.getMessage()).isEqualTo("You cannot subscribe() until the channel "
+					+ "bean is fully initialized by the framework. Do not subscribe in a @Bean definition");
 		}
 	}
 
@@ -259,6 +253,7 @@ public class ExecutorChannelTests {
 			this.count.incrementAndGet();
 			this.latch.countDown();
 		}
+
 	}
 
 	private static class BeforeHandleInterceptor implements ExecutorChannelInterceptor {
@@ -287,14 +282,15 @@ public class ExecutorChannelTests {
 
 		@Override
 		public Message<?> beforeHandle(Message<?> message, MessageChannel channel, MessageHandler handler) {
-			assertNotNull(message);
+			assertThat(message).isNotNull();
 			this.counter.incrementAndGet();
 			return (this.messageToReturn != null ? this.messageToReturn : message);
 		}
 
 		@Override
 		public void afterMessageHandled(Message<?> message, MessageChannel channel, MessageHandler handler,
-										Exception ex) {
+				Exception ex) {
+
 			this.afterHandledInvoked = true;
 		}
 

spring-integration-core/src/test/java/org/springframework/integration/channel/FixedSubscriberChannelTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2014-2016 the original author or authors.
+ * Copyright 2014-2019 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -16,12 +16,9 @@
 
 package org.springframework.integration.channel;
 
-import static org.hamcrest.Matchers.instanceOf;
-import static org.junit.Assert.assertEquals;
-import static org.junit.Assert.assertThat;
-import static org.junit.Assert.fail;
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.assertj.core.api.Assertions.fail;
 
-import org.hamcrest.Matchers;
 import org.junit.Test;
 import org.junit.runner.RunWith;
 
@@ -57,8 +54,8 @@ public class FixedSubscriberChannelTests {
 	public void testHappyDay() {
 		this.in.send(new GenericMessage<String>("foo"));
 		Message<?> out = this.out.receive(0);
-		assertEquals("FOO", out.getPayload());
-		assertThat(this.in, instanceOf(FixedSubscriberChannel.class));
+		assertThat(out.getPayload()).isEqualTo("FOO");
+		assertThat(this.in).isInstanceOf(FixedSubscriberChannel.class);
 	}
 
 	@Test
@@ -70,10 +67,10 @@ public class FixedSubscriberChannelTests {
 			fail("Expected exception");
 		}
 		catch (Exception e) {
-			assertThat(e, instanceOf(BeanCreationException.class));
-			assertThat(e.getCause(), instanceOf(BeanInstantiationException.class));
-			assertThat(e.getCause().getCause(), instanceOf(IllegalArgumentException.class));
-			assertThat(e.getCause().getCause().getMessage(), Matchers.containsString("Cannot instantiate a"));
+			assertThat(e).isInstanceOf(BeanCreationException.class);
+			assertThat(e.getCause()).isInstanceOf(BeanInstantiationException.class);
+			assertThat(e.getCause().getCause()).isInstanceOf(IllegalArgumentException.class);
+			assertThat(e.getCause().getCause().getMessage()).contains("Cannot instantiate a");
 		}
 		if (context != null) {
 			context.close();
@@ -89,8 +86,8 @@ public class FixedSubscriberChannelTests {
 			fail("Expected exception");
 		}
 		catch (Exception e) {
-			assertThat(e, instanceOf(BeanDefinitionParsingException.class));
-			assertThat(e.getMessage(), Matchers.containsString("Only one subscriber is allowed for a FixedSubscriberChannel."));
+			assertThat(e).isInstanceOf(BeanDefinitionParsingException.class);
+			assertThat(e.getMessage()).contains("Only one subscriber is allowed for a FixedSubscriberChannel.");
 		}
 		if (context != null) {
 			context.close();
@@ -106,8 +103,8 @@ public class FixedSubscriberChannelTests {
 			fail("Expected exception");
 		}
 		catch (Exception e) {
-			assertThat(e, instanceOf(IllegalArgumentException.class));
-			assertThat(e.getMessage(), Matchers.containsString("Only one subscriber is allowed for a FixedSubscriberChannel."));
+			assertThat(e).isInstanceOf(IllegalArgumentException.class);
+			assertThat(e.getMessage()).contains("Only one subscriber is allowed for a FixedSubscriberChannel.");
 		}
 		if (context != null) {
 			context.close();
@@ -123,8 +120,8 @@ public class FixedSubscriberChannelTests {
 			fail("Expected exception");
 		}
 		catch (Exception e) {
-			assertThat(e, instanceOf(BeanDefinitionParsingException.class));
-			assertThat(e.getMessage(), Matchers.containsString("Cannot have interceptors when 'fixed-subscriber=\"true\"'"));
+			assertThat(e).isInstanceOf(BeanDefinitionParsingException.class);
+			assertThat(e.getMessage()).contains("Cannot have interceptors when 'fixed-subscriber=\"true\"'");
 		}
 		if (context != null) {
 			context.close();
@@ -140,8 +137,8 @@ public class FixedSubscriberChannelTests {
 			fail("Expected exception");
 		}
 		catch (Exception e) {
-			assertThat(e, instanceOf(BeanDefinitionParsingException.class));
-			assertThat(e.getMessage(), Matchers.containsString("Cannot have 'datatype' when 'fixed-subscriber=\"true\"'"));
+			assertThat(e).isInstanceOf(BeanDefinitionParsingException.class);
+			assertThat(e.getMessage()).contains("Cannot have 'datatype' when 'fixed-subscriber=\"true\"'");
 		}
 		if (context != null) {
 			context.close();
@@ -157,8 +154,8 @@ public class FixedSubscriberChannelTests {
 			fail("Expected exception");
 		}
 		catch (Exception e) {
-			assertThat(e, instanceOf(BeanDefinitionParsingException.class));
-			assertThat(e.getMessage(), Matchers.containsString("Cannot have 'message-converter' when 'fixed-subscriber=\"true\"'"));
+			assertThat(e).isInstanceOf(BeanDefinitionParsingException.class);
+			assertThat(e.getMessage()).contains("Cannot have 'message-converter' when 'fixed-subscriber=\"true\"'");
 		}
 		if (context != null) {
 			context.close();
@@ -174,8 +171,9 @@ public class FixedSubscriberChannelTests {
 			fail("Expected exception");
 		}
 		catch (Exception e) {
-			assertThat(e, instanceOf(BeanDefinitionParsingException.class));
-			assertThat(e.getMessage(), Matchers.containsString("The 'fixed-subscriber' attribute is not allowed when a <queue/> child element is present."));
+			assertThat(e).isInstanceOf(BeanDefinitionParsingException.class);
+			assertThat(e.getMessage())
+					.contains("The 'fixed-subscriber' attribute is not allowed when a <queue/> child element is present.");
 		}
 		if (context != null) {
 			context.close();
@@ -191,8 +189,9 @@ public class FixedSubscriberChannelTests {
 			fail("Expected exception");
 		}
 		catch (Exception e) {
-			assertThat(e, instanceOf(BeanDefinitionParsingException.class));
-			assertThat(e.getMessage(), Matchers.containsString("The 'fixed-subscriber' attribute is not allowed when a <dispatcher/> child element is present."));
+			assertThat(e).isInstanceOf(BeanDefinitionParsingException.class);
+			assertThat(e.getMessage())
+					.contains("The 'fixed-subscriber' attribute is not allowed when a <dispatcher/> child element is present.");
 		}
 		if (context != null) {
 			context.close();

spring-integration-core/src/test/java/org/springframework/integration/channel/MixedDispatcherConfigurationScenarioTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2018 the original author or authors.
+ * Copyright 2002-2019 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -16,8 +16,7 @@
 
 package org.springframework.integration.channel;
 
-import static org.junit.Assert.assertFalse;
-import static org.junit.Assert.assertTrue;
+import static org.assertj.core.api.Assertions.assertThat;
 import static org.mockito.ArgumentMatchers.any;
 import static org.mockito.Mockito.doAnswer;
 import static org.mockito.Mockito.doThrow;
@@ -158,12 +157,12 @@ public class MixedDispatcherConfigurationScenarioTests {
 			executor.execute(messageSenderTask);
 		}
 		start.countDown();
-		assertTrue(allDone.await(10, TimeUnit.SECONDS));
+		assertThat(allDone.await(10, TimeUnit.SECONDS)).isTrue();
 
 		executor.shutdown();
 		executor.awaitTermination(10, TimeUnit.SECONDS);
 
-		assertTrue("not all messages were accepted", failed.get());
+		assertThat(failed.get()).as("not all messages were accepted").isTrue();
 		verify(handlerA, times(TOTAL_EXECUTIONS)).handleMessage(message);
 		verify(handlerB, times(0)).handleMessage(message);
 		verify(exceptionRegistry, times(TOTAL_EXECUTIONS)).add(any(Exception.class));
@@ -199,12 +198,12 @@ public class MixedDispatcherConfigurationScenarioTests {
 			executor.execute(messageSenderTask);
 		}
 		start.countDown();
-		assertTrue(allDone.await(10, TimeUnit.SECONDS));
+		assertThat(allDone.await(10, TimeUnit.SECONDS)).isTrue();
 
 		executor.shutdown();
 		executor.awaitTermination(10, TimeUnit.SECONDS);
 
-		assertTrue("not all messages were accepted", failed.get());
+		assertThat(failed.get()).as("not all messages were accepted").isTrue();
 		verify(handlerA, times(TOTAL_EXECUTIONS)).handleMessage(message);
 		verify(handlerB, times(0)).handleMessage(message);
 		verify(exceptionRegistry, times(TOTAL_EXECUTIONS)).add(any(Exception.class));
@@ -280,12 +279,12 @@ public class MixedDispatcherConfigurationScenarioTests {
 			executor.execute(messageSenderTask);
 		}
 		start.countDown();
-		assertTrue(allDone.await(10, TimeUnit.SECONDS));
+		assertThat(allDone.await(10, TimeUnit.SECONDS)).isTrue();
 
 		executor.shutdown();
 		executor.awaitTermination(10, TimeUnit.SECONDS);
 
-		assertTrue("not all messages were accepted", failed.get());
+		assertThat(failed.get()).as("not all messages were accepted").isTrue();
 		verify(handlerA, times(14)).handleMessage(message);
 		verify(handlerB, times(13)).handleMessage(message);
 		verify(handlerC, times(13)).handleMessage(message);
@@ -333,12 +332,12 @@ public class MixedDispatcherConfigurationScenarioTests {
 			executor.execute(messageSenderTask);
 		}
 		start.countDown();
-		assertTrue(allDone.await(10, TimeUnit.SECONDS));
+		assertThat(allDone.await(10, TimeUnit.SECONDS)).isTrue();
 
 		executor.shutdown();
 		executor.awaitTermination(10, TimeUnit.SECONDS);
 
-		assertTrue("not all messages were accepted", failed.get());
+		assertThat(failed.get()).as("not all messages were accepted").isTrue();
 		verify(handlerA, times(14)).handleMessage(message);
 		verify(handlerB, times(13)).handleMessage(message);
 		verify(handlerC, times(13)).handleMessage(message);
@@ -414,12 +413,12 @@ public class MixedDispatcherConfigurationScenarioTests {
 			executor.execute(messageSenderTask);
 		}
 		start.countDown();
-		assertTrue(allDone.await(10, TimeUnit.SECONDS));
+		assertThat(allDone.await(10, TimeUnit.SECONDS)).isTrue();
 
 		executor.shutdown();
 		executor.awaitTermination(10, TimeUnit.SECONDS);
 
-		assertFalse("not all messages were accepted", failed.get());
+		assertThat(failed.get()).as("not all messages were accepted").isFalse();
 		verify(handlerA, times(TOTAL_EXECUTIONS)).handleMessage(message);
 		verify(handlerB, times(TOTAL_EXECUTIONS)).handleMessage(message);
 		verify(handlerC, never()).handleMessage(message);
@@ -458,7 +457,7 @@ public class MixedDispatcherConfigurationScenarioTests {
 
 		}
 		start.countDown();
-		assertTrue(allDone.await(10, TimeUnit.SECONDS));
+		assertThat(allDone.await(10, TimeUnit.SECONDS)).isTrue();
 
 		executor.shutdown();
 		executor.awaitTermination(10, TimeUnit.SECONDS);

spring-integration-core/src/test/java/org/springframework/integration/channel/P2pChannelTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2017 the original author or authors.
+ * Copyright 2002-2019 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -16,7 +16,7 @@
 
 package org.springframework.integration.channel;
 
-import static org.junit.Assert.assertEquals;
+import static org.assertj.core.api.Assertions.assertThat;
 import static org.mockito.Mockito.doAnswer;
 import static org.mockito.Mockito.mock;
 import static org.mockito.Mockito.times;
@@ -73,21 +73,21 @@ public class P2pChannelTests {
 
 		MessageHandler handler1 = mock(MessageHandler.class);
 		channel.subscribe(handler1);
-		assertEquals(1, channel.getSubscriberCount());
-		assertEquals(String.format(log, 1), logs.remove(0));
+		assertThat(channel.getSubscriberCount()).isEqualTo(1);
+		assertThat(logs.remove(0)).isEqualTo(String.format(log, 1));
 		MessageHandler handler2 = mock(MessageHandler.class);
 		channel.subscribe(handler2);
-		assertEquals(2, channel.getSubscriberCount());
-		assertEquals(String.format(log, 2), logs.remove(0));
+		assertThat(channel.getSubscriberCount()).isEqualTo(2);
+		assertThat(logs.remove(0)).isEqualTo(String.format(log, 2));
 		channel.unsubscribe(handler1);
-		assertEquals(1, channel.getSubscriberCount());
-		assertEquals(String.format(log, 1), logs.remove(0));
+		assertThat(channel.getSubscriberCount()).isEqualTo(1);
+		assertThat(logs.remove(0)).isEqualTo(String.format(log, 1));
 		channel.unsubscribe(handler1);
-		assertEquals(1, channel.getSubscriberCount());
-		assertEquals(0, logs.size());
+		assertThat(channel.getSubscriberCount()).isEqualTo(1);
+		assertThat(logs.size()).isEqualTo(0);
 		channel.unsubscribe(handler2);
-		assertEquals(0, channel.getSubscriberCount());
-		assertEquals(String.format(log, 0), logs.remove(0));
+		assertThat(channel.getSubscriberCount()).isEqualTo(0);
+		assertThat(logs.remove(0)).isEqualTo(String.format(log, 0));
 		verify(logger, times(4)).info(Mockito.anyString());
 	}
 

spring-integration-core/src/test/java/org/springframework/integration/channel/PriorityChannelTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2018 the original author or authors.
+ * Copyright 2002-2019 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -16,11 +16,7 @@
 
 package org.springframework.integration.channel;
 
-import static org.junit.Assert.assertEquals;
-import static org.junit.Assert.assertFalse;
-import static org.junit.Assert.assertNotNull;
-import static org.junit.Assert.assertNull;
-import static org.junit.Assert.assertTrue;
+import static org.assertj.core.api.Assertions.assertThat;
 
 import java.util.Comparator;
 import java.util.concurrent.CountDownLatch;
@@ -45,12 +41,12 @@ public class PriorityChannelTests {
 	@Test
 	public void testCapacityEnforced() {
 		PriorityChannel channel = new PriorityChannel(3);
-		assertTrue(channel.send(new GenericMessage<>("test1"), 0));
-		assertTrue(channel.send(new GenericMessage<>("test2"), 0));
-		assertTrue(channel.send(new GenericMessage<>("test3"), 0));
-		assertFalse(channel.send(new GenericMessage<>("test4"), 0));
+		assertThat(channel.send(new GenericMessage<>("test1"), 0)).isTrue();
+		assertThat(channel.send(new GenericMessage<>("test2"), 0)).isTrue();
+		assertThat(channel.send(new GenericMessage<>("test3"), 0)).isTrue();
+		assertThat(channel.send(new GenericMessage<>("test4"), 0)).isFalse();
 		channel.receive(0);
-		assertTrue(channel.send(new GenericMessage<>("test5")));
+		assertThat(channel.send(new GenericMessage<>("test5"))).isTrue();
 	}
 
 	@Test
@@ -60,7 +56,7 @@ public class PriorityChannelTests {
 			channel.send(new GenericMessage<>(i));
 		}
 		for (int i = 0; i < 1000; i++) {
-			assertEquals(i, channel.receive().getPayload());
+			assertThat(channel.receive().getPayload()).isEqualTo(i);
 		}
 	}
 
@@ -77,11 +73,11 @@ public class PriorityChannelTests {
 		channel.send(priority5);
 		channel.send(priority1);
 		channel.send(priority2);
-		assertEquals("test:10", channel.receive(0).getPayload());
-		assertEquals("test:7", channel.receive(0).getPayload());
-		assertEquals("test:0", channel.receive(0).getPayload());
-		assertEquals("test:-3", channel.receive(0).getPayload());
-		assertEquals("test:-99", channel.receive(0).getPayload());
+		assertThat(channel.receive(0).getPayload()).isEqualTo("test:10");
+		assertThat(channel.receive(0).getPayload()).isEqualTo("test:7");
+		assertThat(channel.receive(0).getPayload()).isEqualTo("test:0");
+		assertThat(channel.receive(0).getPayload()).isEqualTo("test:-3");
+		assertThat(channel.receive(0).getPayload()).isEqualTo("test:-99");
 	}
 
 	// although this test has no assertions it results in ConcurrentModificationException
@@ -110,11 +106,11 @@ public class PriorityChannelTests {
 		channel.send(messageE);
 		channel.send(messageD);
 		channel.send(messageB);
-		assertEquals("A", channel.receive(0).getPayload());
-		assertEquals("B", channel.receive(0).getPayload());
-		assertEquals("C", channel.receive(0).getPayload());
-		assertEquals("D", channel.receive(0).getPayload());
-		assertEquals("E", channel.receive(0).getPayload());
+		assertThat(channel.receive(0).getPayload()).isEqualTo("A");
+		assertThat(channel.receive(0).getPayload()).isEqualTo("B");
+		assertThat(channel.receive(0).getPayload()).isEqualTo("C");
+		assertThat(channel.receive(0).getPayload()).isEqualTo("D");
+		assertThat(channel.receive(0).getPayload()).isEqualTo("E");
 	}
 
 	@Test
@@ -149,14 +145,14 @@ public class PriorityChannelTests {
 		Object receivedSeven = channel.receive(0).getPayload();
 		Object receivedEight = channel.receive(0).getPayload();
 
-		assertEquals(7, receivedOne);
-		assertEquals(8, receivedTwo);
-		assertEquals(5, receivedThree);
-		assertEquals(6, receivedFour);
-		assertEquals(1, receivedFive);
-		assertEquals(2, receivedSix);
-		assertEquals(3, receivedSeven);
-		assertEquals(4, receivedEight);
+		assertThat(receivedOne).isEqualTo(7);
+		assertThat(receivedTwo).isEqualTo(8);
+		assertThat(receivedThree).isEqualTo(5);
+		assertThat(receivedFour).isEqualTo(6);
+		assertThat(receivedFive).isEqualTo(1);
+		assertThat(receivedSix).isEqualTo(2);
+		assertThat(receivedSeven).isEqualTo(3);
+		assertThat(receivedEight).isEqualTo(4);
 	}
 
 	@Test
@@ -187,13 +183,13 @@ public class PriorityChannelTests {
 		Object receivedSix = channel.receive(0).getPayload();
 		Object receivedSeven = channel.receive(0).getPayload();
 
-		assertEquals(4, receivedOne);
-		assertEquals(5, receivedTwo);
-		assertEquals(1, receivedThree);
-		assertEquals(2, receivedFour);
-		assertEquals(3, receivedFive);
-		assertEquals(6, receivedSix);
-		assertEquals(7, receivedSeven);
+		assertThat(receivedOne).isEqualTo(4);
+		assertThat(receivedTwo).isEqualTo(5);
+		assertThat(receivedThree).isEqualTo(1);
+		assertThat(receivedFour).isEqualTo(2);
+		assertThat(receivedFive).isEqualTo(3);
+		assertThat(receivedSix).isEqualTo(6);
+		assertThat(receivedSeven).isEqualTo(7);
 	}
 
 	@Test
@@ -205,9 +201,9 @@ public class PriorityChannelTests {
 		channel.send(lowPriority);
 		channel.send(highPriority);
 		channel.send(nullPriority);
-		assertEquals("test:5", channel.receive(0).getPayload());
-		assertEquals("test:NULL", channel.receive(0).getPayload());
-		assertEquals("test:-5", channel.receive(0).getPayload());
+		assertThat(channel.receive(0).getPayload()).isEqualTo("test:5");
+		assertThat(channel.receive(0).getPayload()).isEqualTo("test:NULL");
+		assertThat(channel.receive(0).getPayload()).isEqualTo("test:-5");
 	}
 
 	@Test
@@ -219,9 +215,9 @@ public class PriorityChannelTests {
 		channel.send(lowPriority);
 		channel.send(highPriority);
 		channel.send(nullPriority);
-		assertEquals("test:5", channel.receive(0).getPayload());
-		assertEquals("test:NULL", channel.receive(0).getPayload());
-		assertEquals("test:-5", channel.receive(0).getPayload());
+		assertThat(channel.receive(0).getPayload()).isEqualTo("test:5");
+		assertThat(channel.receive(0).getPayload()).isEqualTo("test:NULL");
+		assertThat(channel.receive(0).getPayload()).isEqualTo("test:-5");
 	}
 
 	@Test
@@ -231,15 +227,15 @@ public class PriorityChannelTests {
 		ExecutorService executor = Executors.newSingleThreadScheduledExecutor();
 		channel.send(new GenericMessage<>("test-1"));
 		executor.execute(() -> sentSecondMessage.set(channel.send(new GenericMessage<>("test-2"), 10)));
-		assertFalse(sentSecondMessage.get());
+		assertThat(sentSecondMessage.get()).isFalse();
 
 		executor.shutdown();
-		assertTrue(executor.awaitTermination(10, TimeUnit.SECONDS));
+		assertThat(executor.awaitTermination(10, TimeUnit.SECONDS)).isTrue();
 		Message<?> message1 = channel.receive(10000);
-		assertNotNull(message1);
-		assertEquals("test-1", message1.getPayload());
-		assertFalse(sentSecondMessage.get());
-		assertNull(channel.receive(0));
+		assertThat(message1).isNotNull();
+		assertThat(message1.getPayload()).isEqualTo("test-1");
+		assertThat(sentSecondMessage.get()).isFalse();
+		assertThat(channel.receive(0)).isNull();
 	}
 
 	@Test
@@ -253,16 +249,16 @@ public class PriorityChannelTests {
 			sentSecondMessage.set(channel.send(new GenericMessage<>("test-2"), 3000));
 			latch.countDown();
 		});
-		assertFalse(sentSecondMessage.get());
+		assertThat(sentSecondMessage.get()).isFalse();
 		Thread.sleep(10);
 		Message<?> message1 = channel.receive();
-		assertNotNull(message1);
-		assertEquals("test-1", message1.getPayload());
-		assertTrue(latch.await(10000, TimeUnit.MILLISECONDS));
-		assertTrue(sentSecondMessage.get());
+		assertThat(message1).isNotNull();
+		assertThat(message1.getPayload()).isEqualTo("test-1");
+		assertThat(latch.await(10000, TimeUnit.MILLISECONDS)).isTrue();
+		assertThat(sentSecondMessage.get()).isTrue();
 		Message<?> message2 = channel.receive();
-		assertNotNull(message2);
-		assertEquals("test-2", message2.getPayload());
+		assertThat(message2).isNotNull();
+		assertThat(message2.getPayload()).isEqualTo("test-2");
 		executor.shutdownNow();
 	}
 
@@ -273,17 +269,17 @@ public class PriorityChannelTests {
 		ExecutorService executor = Executors.newSingleThreadScheduledExecutor();
 		channel.send(new GenericMessage<String>("test-1"));
 		executor.execute(() -> sentSecondMessage.set(channel.send(new GenericMessage<>("test-2"), -1)));
-		assertFalse(sentSecondMessage.get());
+		assertThat(sentSecondMessage.get()).isFalse();
 		Thread.sleep(10);
 		Message<?> message1 = channel.receive(10000);
-		assertNotNull(message1);
-		assertEquals("test-1", message1.getPayload());
+		assertThat(message1).isNotNull();
+		assertThat(message1.getPayload()).isEqualTo("test-1");
 		executor.shutdown();
-		assertTrue(executor.awaitTermination(10, TimeUnit.SECONDS));
-		assertTrue(sentSecondMessage.get());
+		assertThat(executor.awaitTermination(10, TimeUnit.SECONDS)).isTrue();
+		assertThat(sentSecondMessage.get()).isTrue();
 		Message<?> message2 = channel.receive();
-		assertNotNull(message2);
-		assertEquals("test-2", message2.getPayload());
+		assertThat(message2).isNotNull();
+		assertThat(message2.getPayload()).isEqualTo("test-2");
 	}
 
 

spring-integration-core/src/test/java/org/springframework/integration/channel/PublishSubscribeChannelTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2016 the original author or authors.
+ * Copyright 2016-2019 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -16,9 +16,8 @@
 
 package org.springframework.integration.channel;
 
-import static org.hamcrest.Matchers.equalTo;
-import static org.junit.Assert.assertThat;
-import static org.junit.Assert.fail;
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.assertj.core.api.Assertions.fail;
 import static org.mockito.Mockito.mock;
 
 import java.util.concurrent.Executor;
@@ -44,8 +43,9 @@ public class PublishSubscribeChannelTests {
 			fail("expected Exception");
 		}
 		catch (IllegalStateException e) {
-			assertThat(e.getMessage(), equalTo("When providing an Executor, you cannot subscribe() until the channel "
-					+ "bean is fully initialized by the framework. Do not subscribe in a @Bean definition"));
+			assertThat(e.getMessage()).isEqualTo("When providing an Executor, you cannot subscribe() until the " +
+					"channel "
+					+ "bean is fully initialized by the framework. Do not subscribe in a @Bean definition");
 		}
 	}
 

spring-integration-core/src/test/java/org/springframework/integration/channel/QueueChannelTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2018 the original author or authors.
+ * Copyright 2002-2019 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -16,10 +16,7 @@
 
 package org.springframework.integration.channel;
 
-import static org.junit.Assert.assertEquals;
-import static org.junit.Assert.assertFalse;
-import static org.junit.Assert.assertNotNull;
-import static org.junit.Assert.assertTrue;
+import static org.assertj.core.api.Assertions.assertThat;
 import static org.mockito.BDDMockito.willAnswer;
 import static org.mockito.Mockito.spy;
 
@@ -60,7 +57,7 @@ public class QueueChannelTests {
 			}
 		});
 		channel.send(new GenericMessage<>("testing"));
-		assertTrue(latch.await(10000, TimeUnit.MILLISECONDS));
+		assertThat(latch.await(10000, TimeUnit.MILLISECONDS)).isTrue();
 		exec.shutdownNow();
 	}
 
@@ -76,7 +73,7 @@ public class QueueChannelTests {
 			}
 		});
 		channel.send(new GenericMessage<>("testing"));
-		assertTrue(latch.await(10000, TimeUnit.MILLISECONDS));
+		assertThat(latch.await(10000, TimeUnit.MILLISECONDS)).isTrue();
 		exec.shutdownNow();
 	}
 
@@ -92,7 +89,7 @@ public class QueueChannelTests {
 			}
 		});
 		channel.send(new GenericMessage<>("testing"));
-		assertTrue(latch.await(10000, TimeUnit.MILLISECONDS));
+		assertThat(latch.await(10000, TimeUnit.MILLISECONDS)).isTrue();
 		exec.shutdownNow();
 	}
 
@@ -110,7 +107,7 @@ public class QueueChannelTests {
 		};
 		Runnable sendTask = () -> channel.send(new GenericMessage<>("testing"));
 		singleThreadExecutor.execute(receiveTask1);
-		assertTrue(latch1.await(10, TimeUnit.SECONDS));
+		assertThat(latch1.await(10, TimeUnit.SECONDS)).isTrue();
 		singleThreadExecutor.execute(sendTask);
 		Runnable receiveTask2 = () -> {
 			Message<?> message = channel.receive(0);
@@ -119,7 +116,7 @@ public class QueueChannelTests {
 			}
 		};
 		singleThreadExecutor.execute(receiveTask2);
-		assertTrue(latch2.await(10, TimeUnit.SECONDS));
+		assertThat(latch2.await(10, TimeUnit.SECONDS)).isTrue();
 		singleThreadExecutor.shutdownNow();
 	}
 
@@ -135,8 +132,8 @@ public class QueueChannelTests {
 			latch.countDown();
 		});
 		exec.shutdownNow();
-		assertTrue(latch.await(10, TimeUnit.SECONDS));
-		assertTrue(messageNull.get());
+		assertThat(latch.await(10, TimeUnit.SECONDS)).isTrue();
+		assertThat(messageNull.get()).isTrue();
 	}
 
 	@Test
@@ -151,8 +148,8 @@ public class QueueChannelTests {
 			latch.countDown();
 		});
 		exec.shutdownNow();
-		assertTrue(latch.await(10, TimeUnit.SECONDS));
-		assertTrue(messageNull.get());
+		assertThat(latch.await(10, TimeUnit.SECONDS)).isTrue();
+		assertThat(messageNull.get()).isTrue();
 	}
 
 	@Test
@@ -173,9 +170,9 @@ public class QueueChannelTests {
 				latch.countDown();
 			}
 		});
-		assertTrue(pollLatch.await(10, TimeUnit.SECONDS));
+		assertThat(pollLatch.await(10, TimeUnit.SECONDS)).isTrue();
 		channel.send(new GenericMessage<>("testing"));
-		assertTrue(latch.await(10, TimeUnit.SECONDS));
+		assertThat(latch.await(10, TimeUnit.SECONDS)).isTrue();
 		exec.shutdownNow();
 	}
 
@@ -197,9 +194,9 @@ public class QueueChannelTests {
 				latch.countDown();
 			}
 		});
-		assertTrue(pollLatch.await(10, TimeUnit.SECONDS));
+		assertThat(pollLatch.await(10, TimeUnit.SECONDS)).isTrue();
 		channel.send(new GenericMessage<>("testing"));
-		assertTrue(latch.await(10, TimeUnit.SECONDS));
+		assertThat(latch.await(10, TimeUnit.SECONDS)).isTrue();
 		exec.shutdownNow();
 	}
 
@@ -207,20 +204,20 @@ public class QueueChannelTests {
 	public void testImmediateSend() {
 		QueueChannel channel = new QueueChannel(3);
 		boolean result1 = channel.send(new GenericMessage<>("test-1"));
-		assertTrue(result1);
+		assertThat(result1).isTrue();
 		boolean result2 = channel.send(new GenericMessage<>("test-2"), 100);
-		assertTrue(result2);
+		assertThat(result2).isTrue();
 		boolean result3 = channel.send(new GenericMessage<>("test-3"), 0);
-		assertTrue(result3);
+		assertThat(result3).isTrue();
 		boolean result4 = channel.send(new GenericMessage<>("test-4"), 0);
-		assertFalse(result4);
+		assertThat(result4).isFalse();
 	}
 
 	@Test
 	public void testBlockingSendWithNoTimeout() throws Exception {
 		final QueueChannel channel = new QueueChannel(1);
 		boolean result1 = channel.send(new GenericMessage<>("test-1"));
-		assertTrue(result1);
+		assertThat(result1).isTrue();
 		final CountDownLatch latch = new CountDownLatch(1);
 		ExecutorService exec = Executors.newSingleThreadExecutor();
 		exec.execute(() -> {
@@ -228,14 +225,14 @@ public class QueueChannelTests {
 			latch.countDown();
 		});
 		exec.shutdownNow();
-		assertTrue(latch.await(10, TimeUnit.SECONDS));
+		assertThat(latch.await(10, TimeUnit.SECONDS)).isTrue();
 	}
 
 	@Test
 	public void testBlockingSendWithTimeout() throws Exception {
 		final QueueChannel channel = new QueueChannel(1);
 		boolean result1 = channel.send(new GenericMessage<>("test-1"));
-		assertTrue(result1);
+		assertThat(result1).isTrue();
 		final CountDownLatch latch = new CountDownLatch(1);
 		ExecutorService exec = Executors.newSingleThreadExecutor();
 		exec.execute(() -> {
@@ -243,7 +240,7 @@ public class QueueChannelTests {
 			latch.countDown();
 		});
 		exec.shutdownNow();
-		assertTrue(latch.await(10, TimeUnit.SECONDS));
+		assertThat(latch.await(10, TimeUnit.SECONDS)).isTrue();
 	}
 
 	@Test
@@ -252,21 +249,21 @@ public class QueueChannelTests {
 		GenericMessage<String> message1 = new GenericMessage<>("test1");
 		GenericMessage<String> message2 = new GenericMessage<>("test2");
 		GenericMessage<String> message3 = new GenericMessage<>("test3");
-		assertTrue(channel.send(message1));
-		assertTrue(channel.send(message2));
-		assertFalse(channel.send(message3, 0));
+		assertThat(channel.send(message1)).isTrue();
+		assertThat(channel.send(message2)).isTrue();
+		assertThat(channel.send(message3, 0)).isFalse();
 		List<Message<?>> clearedMessages = channel.clear();
-		assertNotNull(clearedMessages);
-		assertEquals(2, clearedMessages.size());
-		assertTrue(channel.send(message3));
+		assertThat(clearedMessages).isNotNull();
+		assertThat(clearedMessages.size()).isEqualTo(2);
+		assertThat(channel.send(message3)).isTrue();
 	}
 
 	@Test
 	public void testClearEmptyChannel() {
 		QueueChannel channel = new QueueChannel();
 		List<Message<?>> clearedMessages = channel.clear();
-		assertNotNull(clearedMessages);
-		assertEquals(0, clearedMessages.size());
+		assertThat(clearedMessages).isNotNull();
+		assertThat(clearedMessages.size()).isEqualTo(0);
 	}
 
 	@Test
@@ -280,13 +277,13 @@ public class QueueChannelTests {
 				.setExpirationDate(past).build();
 		Message<String> unexpiredMessage = MessageBuilder.withPayload("test2")
 				.setExpirationDate(future).build();
-		assertTrue(channel.send(expiredMessage, 0));
-		assertTrue(channel.send(unexpiredMessage, 0));
-		assertFalse(channel.send(new GenericMessage<>("atCapacity"), 0));
+		assertThat(channel.send(expiredMessage, 0)).isTrue();
+		assertThat(channel.send(unexpiredMessage, 0)).isTrue();
+		assertThat(channel.send(new GenericMessage<>("atCapacity"), 0)).isFalse();
 		List<Message<?>> purgedMessages = channel.purge(new UnexpiredMessageSelector());
-		assertNotNull(purgedMessages);
-		assertEquals(1, purgedMessages.size());
-		assertTrue(channel.send(new GenericMessage<>("roomAvailable"), 0));
+		assertThat(purgedMessages).isNotNull();
+		assertThat(purgedMessages.size()).isEqualTo(1);
+		assertThat(channel.send(new GenericMessage<>("roomAvailable"), 0)).isTrue();
 	}
 
 	@Rule

spring-integration-core/src/test/java/org/springframework/integration/channel/TransactionSynchronizationQueueChannelTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2017 the original author or authors.
+ * Copyright 2002-2019 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -16,9 +16,7 @@
 
 package org.springframework.integration.channel;
 
-import static org.junit.Assert.assertEquals;
-import static org.junit.Assert.assertNotNull;
-import static org.junit.Assert.assertSame;
+import static org.assertj.core.api.Assertions.assertThat;
 
 import org.junit.Before;
 import org.junit.Test;
@@ -65,17 +63,17 @@ public class TransactionSynchronizationQueueChannelTests {
 		GenericMessage<String> sentMessage = new GenericMessage<>("hello");
 		this.queueChannel.send(sentMessage);
 		Message<?> message = this.good.receive(10000);
-		assertNotNull(message);
-		assertEquals("hello", message.getPayload());
-		assertSame(message, sentMessage);
+		assertThat(message).isNotNull();
+		assertThat(message.getPayload()).isEqualTo("hello");
+		assertThat(sentMessage).isSameAs(message);
 	}
 
 	@Test
 	public void testRollback() throws Exception {
 		this.queueChannel.send(new GenericMessage<>("fail"));
 		Message<?> message = this.good.receive(10000);
-		assertNotNull(message);
-		assertEquals("retry:fail", message.getPayload());
+		assertThat(message).isNotNull();
+		assertThat(message.getPayload()).isEqualTo("retry:fail");
 	}
 
 	@Test
@@ -84,10 +82,10 @@ public class TransactionSynchronizationQueueChannelTests {
 				.setHeader("foo", "bar").build();
 		queueChannel2.send(sentMessage);
 		Message<?> message = good.receive(10000);
-		assertNotNull(message);
-		assertEquals("hello processed ok from queueChannel2", message.getPayload());
-		assertNotNull(message.getHeaders().get("foo"));
-		assertEquals("bar", message.getHeaders().get("foo"));
+		assertThat(message).isNotNull();
+		assertThat(message.getPayload()).isEqualTo("hello processed ok from queueChannel2");
+		assertThat(message.getHeaders().get("foo")).isNotNull();
+		assertThat(message.getHeaders().get("foo")).isEqualTo("bar");
 	}
 
 	public static class Service {

spring-integration-core/src/test/java/org/springframework/integration/channel/config/AutoGeneratedChannelTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2009 the original author or authors.
+ * Copyright 2002-2019 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -16,8 +16,7 @@
 
 package org.springframework.integration.channel.config;
 
-import static org.junit.Assert.assertEquals;
-import static org.junit.Assert.assertNotNull;
+import static org.assertj.core.api.Assertions.assertThat;
 
 import org.junit.Test;
 import org.junit.runner.RunWith;
@@ -41,8 +40,8 @@ public class AutoGeneratedChannelTests {
 	@Test
 	public void checkConfig() {
 		Object input = context.getBean("input");
-		assertNotNull(input);
-		assertEquals(DirectChannel.class, input.getClass());
+		assertThat(input).isNotNull();
+		assertThat(input.getClass()).isEqualTo(DirectChannel.class);
 	}
 
 }

spring-integration-core/src/test/java/org/springframework/integration/channel/config/ChannelCapacityPlaceholderTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2016 the original author or authors.
+ * Copyright 2002-2019 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -16,8 +16,7 @@
 
 package org.springframework.integration.channel.config;
 
-import static org.junit.Assert.assertEquals;
-import static org.junit.Assert.assertNotNull;
+import static org.assertj.core.api.Assertions.assertThat;
 
 import org.junit.Test;
 import org.junit.runner.RunWith;
@@ -44,25 +43,25 @@ public class ChannelCapacityPlaceholderTests {
 	@Test
 	public void verifyCapacityValueChanges() {
 		QueueChannel channel = context.getBean("channel", QueueChannel.class);
-		assertNotNull(channel);
-		assertEquals(99, channel.getRemainingCapacity());
+		assertThat(channel).isNotNull();
+		assertThat(channel.getRemainingCapacity()).isEqualTo(99);
 		channel.send(MessageBuilder.withPayload("test1").build());
 		channel.send(MessageBuilder.withPayload("test2").build());
-		assertEquals(97, channel.getRemainingCapacity());
-		assertNotNull(channel.receive(0));
-		assertEquals(98, channel.getRemainingCapacity());
+		assertThat(channel.getRemainingCapacity()).isEqualTo(97);
+		assertThat(channel.receive(0)).isNotNull();
+		assertThat(channel.getRemainingCapacity()).isEqualTo(98);
 	}
 
 	@Test
 	public void testCapacityOnPriorityChannel() {
 		PriorityChannel channel = context.getBean("priorityChannel", PriorityChannel.class);
-		assertNotNull(channel);
-		assertEquals(99, channel.getRemainingCapacity());
+		assertThat(channel).isNotNull();
+		assertThat(channel.getRemainingCapacity()).isEqualTo(99);
 		channel.send(MessageBuilder.withPayload("test1").build());
 		channel.send(MessageBuilder.withPayload("test2").build());
-		assertEquals(97, channel.getRemainingCapacity());
-		assertNotNull(channel.receive(0));
-		assertEquals(98, channel.getRemainingCapacity());
+		assertThat(channel.getRemainingCapacity()).isEqualTo(97);
+		assertThat(channel.receive(0)).isNotNull();
+		assertThat(channel.getRemainingCapacity()).isEqualTo(98);
 	}
 
 }

spring-integration-core/src/test/java/org/springframework/integration/channel/config/ChannelParserTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2018 the original author or authors.
+ * Copyright 2002-2019 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -16,15 +16,7 @@
 
 package org.springframework.integration.channel.config;
 
-import static org.hamcrest.CoreMatchers.instanceOf;
-import static org.hamcrest.CoreMatchers.is;
-import static org.junit.Assert.assertEquals;
-import static org.junit.Assert.assertFalse;
-import static org.junit.Assert.assertNotNull;
-import static org.junit.Assert.assertNull;
-import static org.junit.Assert.assertSame;
-import static org.junit.Assert.assertThat;
-import static org.junit.Assert.assertTrue;
+import static org.assertj.core.api.Assertions.assertThat;
 
 import java.util.concurrent.Executor;
 
@@ -89,28 +81,28 @@ public class ChannelParserTests {
 		MessageChannel channel = (MessageChannel) context.getBean("capacityChannel");
 		for (int i = 0; i < 10; i++) {
 			boolean result = channel.send(new GenericMessage<String>("test"), 10);
-			assertTrue(result);
+			assertThat(result).isTrue();
 		}
-		assertFalse(channel.send(new GenericMessage<String>("test"), 3));
+		assertThat(channel.send(new GenericMessage<String>("test"), 3)).isFalse();
 	}
 
 	@Test
 	public void testDirectChannelByDefault() throws InterruptedException {
 		MessageChannel channel = (MessageChannel) context.getBean("defaultChannel");
-		assertThat(channel, instanceOf(DirectChannel.class));
+		assertThat(channel).isInstanceOf(DirectChannel.class);
 		DirectFieldAccessor accessor = new DirectFieldAccessor(channel);
 		Object dispatcher = accessor.getPropertyValue("dispatcher");
-		assertThat(dispatcher, is(instanceOf(UnicastingDispatcher.class)));
-		assertThat(new DirectFieldAccessor(dispatcher).getPropertyValue("loadBalancingStrategy"),
-				is(instanceOf(RoundRobinLoadBalancingStrategy.class)));
+		assertThat(dispatcher).isInstanceOf(UnicastingDispatcher.class);
+		assertThat(new DirectFieldAccessor(dispatcher).getPropertyValue("loadBalancingStrategy"))
+				.isInstanceOf(RoundRobinLoadBalancingStrategy.class);
 	}
 
 	@Test
 	public void testExecutorChannel() throws InterruptedException {
 		MessageChannel channel = context.getBean("executorChannel", MessageChannel.class);
-		assertThat(channel, instanceOf(ExecutorChannel.class));
-		assertNotNull(TestUtils.getPropertyValue(channel, "messageConverter"));
-		assertNotNull(TestUtils.getPropertyValue(channel, "messageConverter.conversionService"));
+		assertThat(channel).isInstanceOf(ExecutorChannel.class);
+		assertThat(TestUtils.getPropertyValue(channel, "messageConverter")).isNotNull();
+		assertThat(TestUtils.getPropertyValue(channel, "messageConverter.conversionService")).isNotNull();
 	}
 
 	@Test
@@ -118,63 +110,63 @@ public class ChannelParserTests {
 		ClassPathXmlApplicationContext context = new ClassPathXmlApplicationContext(
 				"ChannelParserTests-no-converter-context.xml", this.getClass());
 		MessageChannel channel = context.getBean("executorChannel", MessageChannel.class);
-		assertThat(channel, instanceOf(ExecutorChannel.class));
-		assertNotNull(TestUtils.getPropertyValue(channel, "messageConverter"));
-		assertNotNull(TestUtils.getPropertyValue(channel, "messageConverter.conversionService"));
+		assertThat(channel).isInstanceOf(ExecutorChannel.class);
+		assertThat(TestUtils.getPropertyValue(channel, "messageConverter")).isNotNull();
+		assertThat(TestUtils.getPropertyValue(channel, "messageConverter.conversionService")).isNotNull();
 		context.close();
 	}
 
 	@Test
 	public void channelWithFailoverDispatcherAttribute() throws Exception {
 		MessageChannel channel = (MessageChannel) context.getBean("channelWithFailover");
-		assertEquals(DirectChannel.class, channel.getClass());
+		assertThat(channel.getClass()).isEqualTo(DirectChannel.class);
 		DirectFieldAccessor accessor = new DirectFieldAccessor(channel);
 		Object dispatcher = accessor.getPropertyValue("dispatcher");
-		assertThat(dispatcher, is(instanceOf(UnicastingDispatcher.class)));
-		assertNull(new DirectFieldAccessor(dispatcher).getPropertyValue("loadBalancingStrategy"));
+		assertThat(dispatcher).isInstanceOf(UnicastingDispatcher.class);
+		assertThat(new DirectFieldAccessor(dispatcher).getPropertyValue("loadBalancingStrategy")).isNull();
 	}
 
 	@Test
 	public void testPublishSubscribeChannel() throws InterruptedException {
 		MessageChannel channel = (MessageChannel) context.getBean("publishSubscribeChannel");
-		assertEquals(PublishSubscribeChannel.class, channel.getClass());
+		assertThat(channel.getClass()).isEqualTo(PublishSubscribeChannel.class);
 	}
 
 	@Test
 	public void testPublishSubscribeChannelWithTaskExecutorReference() throws InterruptedException {
 		MessageChannel channel = (MessageChannel) context.getBean("publishSubscribeChannelWithTaskExecutorRef");
-		assertEquals(PublishSubscribeChannel.class, channel.getClass());
+		assertThat(channel.getClass()).isEqualTo(PublishSubscribeChannel.class);
 		DirectFieldAccessor accessor = new DirectFieldAccessor(channel);
 		accessor = new DirectFieldAccessor(accessor.getPropertyValue("dispatcher"));
 		Object executorProperty = accessor.getPropertyValue("executor");
-		assertNotNull(executorProperty);
-		assertEquals(ErrorHandlingTaskExecutor.class, executorProperty.getClass());
+		assertThat(executorProperty).isNotNull();
+		assertThat(executorProperty.getClass()).isEqualTo(ErrorHandlingTaskExecutor.class);
 		DirectFieldAccessor executorAccessor = new DirectFieldAccessor(executorProperty);
 		Executor innerExecutor = (Executor) executorAccessor.getPropertyValue("executor");
 		Object executorBean = context.getBean("taskExecutor");
-		assertEquals(executorBean, innerExecutor);
+		assertThat(innerExecutor).isEqualTo(executorBean);
 	}
 
 	@Test
 	public void channelWithCustomQueue() {
 		Object customQueue = context.getBean("customQueue");
 		Object channelWithCustomQueue = context.getBean("channelWithCustomQueue");
-		assertEquals(QueueChannel.class, channelWithCustomQueue.getClass());
+		assertThat(channelWithCustomQueue.getClass()).isEqualTo(QueueChannel.class);
 		Object actualQueue = new DirectFieldAccessor(channelWithCustomQueue).getPropertyValue("queue");
-		assertSame(customQueue, actualQueue);
+		assertThat(actualQueue).isSameAs(customQueue);
 	}
 
 	@Test
 	public void testDatatypeChannelWithCorrectType() {
 		MessageChannel channel = (MessageChannel) context.getBean("integerChannel");
-		assertTrue(channel.send(new GenericMessage<Integer>(123)));
+		assertThat(channel.send(new GenericMessage<Integer>(123))).isTrue();
 	}
 
 	@Test(expected = MessageDeliveryException.class)
 	public void testDatatypeChannelWithIncorrectType() {
 		MessageChannel channel = (MessageChannel) context.getBean("integerChannel");
 		channel.send(new GenericMessage<String>("incorrect type"));
-		assertTrue(TestUtils.getPropertyValue(channel, "messageConverter") instanceof UselessMessageConverter);
+		assertThat(TestUtils.getPropertyValue(channel, "messageConverter") instanceof UselessMessageConverter).isTrue();
 	}
 
 	@Test
@@ -183,25 +175,25 @@ public class ChannelParserTests {
 				new ClassPathXmlApplicationContext("channelParserGlobalConverterTests.xml", getClass());
 		MessageChannel channel = context.getBean("integerChannel", MessageChannel.class);
 		context.close();
-		assertTrue(TestUtils.getPropertyValue(channel, "messageConverter") instanceof UselessMessageConverter);
+		assertThat(TestUtils.getPropertyValue(channel, "messageConverter") instanceof UselessMessageConverter).isTrue();
 	}
 
 	@Test
 	public void testDatatypeChannelWithAssignableSubTypes() {
 		MessageChannel channel = (MessageChannel) context.getBean("numberChannel");
-		assertTrue(channel.send(new GenericMessage<>(123)));
-		assertTrue(channel.send(new GenericMessage<>(123.45)));
-		assertTrue(channel.send(new GenericMessage<>(Boolean.TRUE)));
-		assertThat(TestUtils.getPropertyValue(channel, "messageConverter"),
-				instanceOf(DefaultDatatypeChannelMessageConverter.class));
-		assertNotNull(TestUtils.getPropertyValue(channel, "messageConverter.conversionService"));
+		assertThat(channel.send(new GenericMessage<>(123))).isTrue();
+		assertThat(channel.send(new GenericMessage<>(123.45))).isTrue();
+		assertThat(channel.send(new GenericMessage<>(Boolean.TRUE))).isTrue();
+		assertThat(TestUtils.getPropertyValue(channel, "messageConverter"))
+				.isInstanceOf(DefaultDatatypeChannelMessageConverter.class);
+		assertThat(TestUtils.getPropertyValue(channel, "messageConverter.conversionService")).isNotNull();
 	}
 
 	@Test
 	public void testMultipleDatatypeChannelWithCorrectTypes() {
 		MessageChannel channel = (MessageChannel) context.getBean("stringOrNumberChannel");
-		assertTrue(channel.send(new GenericMessage<>(123)));
-		assertTrue(channel.send(new GenericMessage<>("accepted type")));
+		assertThat(channel.send(new GenericMessage<>(123))).isTrue();
+		assertThat(channel.send(new GenericMessage<>("accepted type"))).isTrue();
 	}
 
 	@Test(expected = MessageDeliveryException.class)
@@ -216,12 +208,12 @@ public class ChannelParserTests {
 				new ClassPathXmlApplicationContext("channelInterceptorParserTests.xml", getClass());
 		PollableChannel channel = (PollableChannel) context.getBean("channelWithInterceptorRef");
 		TestChannelInterceptor interceptor = (TestChannelInterceptor) context.getBean("interceptor");
-		assertEquals(0, interceptor.getSendCount());
+		assertThat(interceptor.getSendCount()).isEqualTo(0);
 		channel.send(new GenericMessage<>("test"));
-		assertEquals(1, interceptor.getSendCount());
-		assertEquals(0, interceptor.getReceiveCount());
+		assertThat(interceptor.getSendCount()).isEqualTo(1);
+		assertThat(interceptor.getReceiveCount()).isEqualTo(0);
 		channel.receive();
-		assertEquals(1, interceptor.getReceiveCount());
+		assertThat(interceptor.getReceiveCount()).isEqualTo(1);
 		context.close();
 	}
 
@@ -232,7 +224,7 @@ public class ChannelParserTests {
 		PollableChannel channel = (PollableChannel) context.getBean("channelWithInterceptorInnerBean");
 		channel.send(new GenericMessage<String>("test"));
 		Message<?> transformed = channel.receive(1000);
-		assertEquals("TEST", transformed.getPayload());
+		assertThat(transformed.getPayload()).isEqualTo("TEST");
 		context.close();
 	}
 
@@ -248,9 +240,9 @@ public class ChannelParserTests {
 		Message<?> reply1 = channel.receive(0);
 		Message<?> reply2 = channel.receive(0);
 		Message<?> reply3 = channel.receive(0);
-		assertEquals("high", reply1.getPayload());
-		assertEquals("mid", reply2.getPayload());
-		assertEquals("low", reply3.getPayload());
+		assertThat(reply1.getPayload()).isEqualTo("high");
+		assertThat(reply2.getPayload()).isEqualTo("mid");
+		assertThat(reply3.getPayload()).isEqualTo("low");
 	}
 
 	@Test
@@ -264,10 +256,10 @@ public class ChannelParserTests {
 		Message<?> reply2 = channel.receive(0);
 		Message<?> reply3 = channel.receive(0);
 		Message<?> reply4 = channel.receive(0);
-		assertEquals("A", reply1.getPayload());
-		assertEquals("B", reply2.getPayload());
-		assertEquals("C", reply3.getPayload());
-		assertEquals("D", reply4.getPayload());
+		assertThat(reply1.getPayload()).isEqualTo("A");
+		assertThat(reply2.getPayload()).isEqualTo("B");
+		assertThat(reply3.getPayload()).isEqualTo("C");
+		assertThat(reply4.getPayload()).isEqualTo("D");
 	}
 
 	@Test
@@ -276,18 +268,18 @@ public class ChannelParserTests {
 		channel.send(new GenericMessage<>(3));
 		channel.send(new GenericMessage<>(2));
 		channel.send(new GenericMessage<>(1));
-		assertEquals(1, channel.receive(0).getPayload());
-		assertEquals(2, channel.receive(0).getPayload());
-		assertEquals(3, channel.receive(0).getPayload());
+		assertThat(channel.receive(0).getPayload()).isEqualTo(1);
+		assertThat(channel.receive(0).getPayload()).isEqualTo(2);
+		assertThat(channel.receive(0).getPayload()).isEqualTo(3);
 		boolean threwException = false;
 		try {
 			channel.send(new GenericMessage<>("wrong type"));
 		}
 		catch (MessageDeliveryException e) {
-			assertEquals("wrong type", e.getFailedMessage().getPayload());
+			assertThat(e.getFailedMessage().getPayload()).isEqualTo("wrong type");
 			threwException = true;
 		}
-		assertTrue(threwException);
+		assertThat(threwException).isTrue();
 	}
 
 	public static class TestInterceptor implements ChannelInterceptor {

spring-integration-core/src/test/java/org/springframework/integration/channel/config/ChannelWithCustomQueueParserTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2016 the original author or authors.
+ * Copyright 2002-2019 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -16,10 +16,7 @@
 
 package org.springframework.integration.channel.config;
 
-import static org.hamcrest.Matchers.instanceOf;
-import static org.hamcrest.Matchers.is;
-import static org.junit.Assert.assertNotNull;
-import static org.junit.Assert.assertThat;
+import static org.assertj.core.api.Assertions.assertThat;
 
 import java.util.concurrent.ArrayBlockingQueue;
 import java.util.concurrent.BlockingQueue;
@@ -54,16 +51,16 @@ public class ChannelWithCustomQueueParserTests {
 
 	@Test
 	public void parseConfig() throws Exception {
-		assertNotNull(customQueueChannel);
+		assertThat(customQueueChannel).isNotNull();
 	}
 
 	@Test
 	public void queueTypeSet() throws Exception {
 		DirectFieldAccessor accessor = new DirectFieldAccessor(customQueueChannel);
 		Object queue = accessor.getPropertyValue("queue");
-		assertNotNull(queue);
-		assertThat(queue, is(instanceOf(ArrayBlockingQueue.class)));
-		assertThat(((BlockingQueue<?>) queue).remainingCapacity(), is(2));
+		assertThat(queue).isNotNull();
+		assertThat(queue).isInstanceOf(ArrayBlockingQueue.class);
+		assertThat(((BlockingQueue<?>) queue).remainingCapacity()).isEqualTo(2);
 	}
 
 }

spring-integration-core/src/test/java/org/springframework/integration/channel/config/DispatchingChannelParserTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2013 the original author or authors.
+ * Copyright 2002-2019 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -16,18 +16,12 @@
 
 package org.springframework.integration.channel.config;
 
-import static org.junit.Assert.assertEquals;
-import static org.junit.Assert.assertFalse;
-import static org.junit.Assert.assertNull;
-import static org.junit.Assert.assertSame;
-import static org.junit.Assert.assertThat;
-import static org.junit.Assert.assertTrue;
+import static org.assertj.core.api.Assertions.assertThat;
 
 import java.util.Collection;
 import java.util.Iterator;
 import java.util.Map;
 
-import org.hamcrest.Matchers;
 import org.junit.Test;
 import org.junit.runner.RunWith;
 
@@ -66,72 +60,73 @@ public class DispatchingChannelParserTests {
 	@Test
 	public void taskExecutorOnly() {
 		MessageChannel channel = channels.get("taskExecutorOnly");
-		assertEquals(ExecutorChannel.class, channel.getClass());
+		assertThat(channel.getClass()).isEqualTo(ExecutorChannel.class);
 		Object executor = getDispatcherProperty("executor", channel);
-		assertEquals(ErrorHandlingTaskExecutor.class, executor.getClass());
-		assertSame(context.getBean("taskExecutor"),
-				new DirectFieldAccessor(executor).getPropertyValue("executor"));
-		assertTrue((Boolean) getDispatcherProperty("failover", channel));
-		assertEquals(RoundRobinLoadBalancingStrategy.class,
-				getDispatcherProperty("loadBalancingStrategy", channel).getClass());
+		assertThat(executor.getClass()).isEqualTo(ErrorHandlingTaskExecutor.class);
+		assertThat(new DirectFieldAccessor(executor).getPropertyValue("executor"))
+				.isSameAs(context.getBean("taskExecutor"));
+		assertThat((Boolean) getDispatcherProperty("failover", channel)).isTrue();
+		assertThat(getDispatcherProperty("loadBalancingStrategy", channel).getClass())
+				.isEqualTo(RoundRobinLoadBalancingStrategy.class);
 	}
 
 	@Test
 	public void failoverFalse() {
 		MessageChannel channel = channels.get("failoverFalse");
-		assertEquals(DirectChannel.class, channel.getClass());
-		assertFalse((Boolean) getDispatcherProperty("failover", channel));
-		assertEquals(RoundRobinLoadBalancingStrategy.class,
-				getDispatcherProperty("loadBalancingStrategy", channel).getClass());
+		assertThat(channel.getClass()).isEqualTo(DirectChannel.class);
+		assertThat((Boolean) getDispatcherProperty("failover", channel)).isFalse();
+		assertThat(getDispatcherProperty("loadBalancingStrategy", channel).getClass())
+				.isEqualTo(RoundRobinLoadBalancingStrategy.class);
 	}
 
 	@Test
 	public void failoverTrue() {
 		MessageChannel channel = channels.get("failoverTrue");
-		assertEquals(DirectChannel.class, channel.getClass());
-		assertTrue((Boolean) getDispatcherProperty("failover", channel));
-		assertEquals(RoundRobinLoadBalancingStrategy.class,
-				getDispatcherProperty("loadBalancingStrategy", channel).getClass());
+		assertThat(channel.getClass()).isEqualTo(DirectChannel.class);
+		assertThat((Boolean) getDispatcherProperty("failover", channel)).isTrue();
+		assertThat(getDispatcherProperty("loadBalancingStrategy", channel).getClass())
+				.isEqualTo(RoundRobinLoadBalancingStrategy.class);
 	}
 
 	@Test
 	public void loadBalancerDisabled() {
 		MessageChannel channel = channels.get("loadBalancerDisabled");
-		assertEquals(DirectChannel.class, channel.getClass());
-		assertTrue((Boolean) getDispatcherProperty("failover", channel));
-		assertNull(getDispatcherProperty("loadBalancingStrategy", channel));
+		assertThat(channel.getClass()).isEqualTo(DirectChannel.class);
+		assertThat((Boolean) getDispatcherProperty("failover", channel)).isTrue();
+		assertThat(getDispatcherProperty("loadBalancingStrategy", channel)).isNull();
 	}
 
 	@Test
 	public void loadBalancerDisabledAndTaskExecutor() {
 		MessageChannel channel = channels.get("loadBalancerDisabledAndTaskExecutor");
-		assertEquals(ExecutorChannel.class, channel.getClass());
-		assertTrue((Boolean) getDispatcherProperty("failover", channel));
-		assertNull(getDispatcherProperty("loadBalancingStrategy", channel));
+		assertThat(channel.getClass()).isEqualTo(ExecutorChannel.class);
+		assertThat((Boolean) getDispatcherProperty("failover", channel)).isTrue();
+		assertThat(getDispatcherProperty("loadBalancingStrategy", channel)).isNull();
 		Object executor = getDispatcherProperty("executor", channel);
-		assertEquals(ErrorHandlingTaskExecutor.class, executor.getClass());
-		assertSame(context.getBean("taskExecutor"),
-				new DirectFieldAccessor(executor).getPropertyValue("executor"));
+		assertThat(executor.getClass()).isEqualTo(ErrorHandlingTaskExecutor.class);
+		assertThat(new DirectFieldAccessor(executor).getPropertyValue("executor"))
+				.isSameAs(context.getBean("taskExecutor"));
 	}
 
 	@Test
 	public void roundRobinLoadBalancerAndTaskExecutor() {
 		MessageChannel channel = channels.get("roundRobinLoadBalancerAndTaskExecutor");
-		assertEquals(ExecutorChannel.class, channel.getClass());
-		assertTrue((Boolean) getDispatcherProperty("failover", channel));
-		assertEquals(RoundRobinLoadBalancingStrategy.class,
-				getDispatcherProperty("loadBalancingStrategy", channel).getClass());
+		assertThat(channel.getClass()).isEqualTo(ExecutorChannel.class);
+		assertThat((Boolean) getDispatcherProperty("failover", channel)).isTrue();
+		assertThat(getDispatcherProperty("loadBalancingStrategy", channel).getClass())
+				.isEqualTo(RoundRobinLoadBalancingStrategy.class);
 		Object executor = getDispatcherProperty("executor", channel);
-		assertEquals(ErrorHandlingTaskExecutor.class, executor.getClass());
-		assertSame(context.getBean("taskExecutor"),
-				new DirectFieldAccessor(executor).getPropertyValue("executor"));
+		assertThat(executor.getClass()).isEqualTo(ErrorHandlingTaskExecutor.class);
+		assertThat(new DirectFieldAccessor(executor).getPropertyValue("executor"))
+				.isSameAs(context.getBean("taskExecutor"));
 	}
 
 	@Test
 	public void loadBalancerRef() {
 		MessageChannel channel = channels.get("lbRefChannel");
-		LoadBalancingStrategy lbStrategy = TestUtils.getPropertyValue(channel, "dispatcher.loadBalancingStrategy", LoadBalancingStrategy.class);
-		assertTrue(lbStrategy instanceof SampleLoadBalancingStrategy);
+		LoadBalancingStrategy lbStrategy = TestUtils.getPropertyValue(channel, "dispatcher.loadBalancingStrategy",
+				LoadBalancingStrategy.class);
+		assertThat(lbStrategy instanceof SampleLoadBalancingStrategy).isTrue();
 	}
 
 	@Test
@@ -141,7 +136,7 @@ public class DispatchingChannelParserTests {
 			new ClassPathXmlApplicationContext("ChannelWithLoadBalancerRef-fail-config.xml", this.getClass()).close();
 		}
 		catch (BeanDefinitionParsingException e) {
-			assertThat(e.getMessage(), Matchers.containsString("'load-balancer' and 'load-balancer-ref' are mutually exclusive"));
+			assertThat(e.getMessage()).contains("'load-balancer' and 'load-balancer-ref' are mutually exclusive");
 		}
 
 	}

spring-integration-core/src/test/java/org/springframework/integration/channel/config/RendezvousChannelParserTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2016 the original author or authors.
+ * Copyright 2002-2019 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -16,7 +16,7 @@
 
 package org.springframework.integration.channel.config;
 
-import static org.junit.Assert.assertEquals;
+import static org.assertj.core.api.Assertions.assertThat;
 
 import org.junit.Test;
 
@@ -35,7 +35,7 @@ public class RendezvousChannelParserTests {
 		ClassPathXmlApplicationContext context = new ClassPathXmlApplicationContext(
 				"rendezvousChannelParserTests.xml", RendezvousChannelParserTests.class);
 		MessageChannel channel = (MessageChannel) context.getBean("channel");
-		assertEquals(RendezvousChannel.class, channel.getClass());
+		assertThat(channel.getClass()).isEqualTo(RendezvousChannel.class);
 		context.close();
 	}
 

spring-integration-core/src/test/java/org/springframework/integration/channel/config/ThreadLocalChannelParserTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2017 the original author or authors.
+ * Copyright 2002-2019 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -16,9 +16,7 @@
 
 package org.springframework.integration.channel.config;
 
-import static org.junit.Assert.assertEquals;
-import static org.junit.Assert.assertNull;
-import static org.junit.Assert.assertTrue;
+import static org.assertj.core.api.Assertions.assertThat;
 
 import java.util.ArrayList;
 import java.util.List;
@@ -67,10 +65,10 @@ public class ThreadLocalChannelParserTests {
 			simpleChannel.send(new GenericMessage<String>("crap"));
 			latch.countDown();
 		});
-		assertTrue(latch.await(10, TimeUnit.SECONDS));
-		assertEquals("test", simpleChannel.receive(10).getPayload());
+		assertThat(latch.await(10, TimeUnit.SECONDS)).isTrue();
+		assertThat(simpleChannel.receive(10).getPayload()).isEqualTo("test");
 		// Message sent on another thread is not collected here
-		assertEquals(null, simpleChannel.receive(10));
+		assertThat(simpleChannel.receive(10)).isEqualTo(null);
 	}
 
 	@Test
@@ -91,24 +89,24 @@ public class ThreadLocalChannelParserTests {
 			otherThreadResults.add(channelWithInterceptor.receive(0));
 			latch.countDown();
 		});
-		assertTrue(latch.await(10, TimeUnit.SECONDS));
-		assertEquals(2, otherThreadResults.size());
-		assertNull(otherThreadResults.get(0));
-		assertNull(otherThreadResults.get(1));
-		assertEquals("test-1.1", simpleChannel.receive(0).getPayload());
-		assertEquals("test-1.2", simpleChannel.receive(0).getPayload());
-		assertEquals("test-1.3", simpleChannel.receive(0).getPayload());
-		assertNull(simpleChannel.receive(0));
-		assertEquals("test-2.1", channelWithInterceptor.receive(0).getPayload());
-		assertEquals("test-2.2", channelWithInterceptor.receive(0).getPayload());
-		assertNull(channelWithInterceptor.receive(0));
+		assertThat(latch.await(10, TimeUnit.SECONDS)).isTrue();
+		assertThat(otherThreadResults.size()).isEqualTo(2);
+		assertThat(otherThreadResults.get(0)).isNull();
+		assertThat(otherThreadResults.get(1)).isNull();
+		assertThat(simpleChannel.receive(0).getPayload()).isEqualTo("test-1.1");
+		assertThat(simpleChannel.receive(0).getPayload()).isEqualTo("test-1.2");
+		assertThat(simpleChannel.receive(0).getPayload()).isEqualTo("test-1.3");
+		assertThat(simpleChannel.receive(0)).isNull();
+		assertThat(channelWithInterceptor.receive(0).getPayload()).isEqualTo("test-2.1");
+		assertThat(channelWithInterceptor.receive(0).getPayload()).isEqualTo("test-2.2");
+		assertThat(channelWithInterceptor.receive(0)).isNull();
 	}
 
 	@Test
 	public void testInterceptor() {
 		int before = interceptor.getSendCount();
 		channelWithInterceptor.send(new GenericMessage<String>("test"));
-		assertEquals(before + 1, interceptor.getSendCount());
+		assertThat(interceptor.getSendCount()).isEqualTo(before + 1);
 	}
 
 }

spring-integration-core/src/test/java/org/springframework/integration/channel/interceptor/ChannelInterceptorTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2018 the original author or authors.
+ * Copyright 2002-2019 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -16,13 +16,7 @@
 
 package org.springframework.integration.channel.interceptor;
 
-import static org.junit.Assert.assertEquals;
-import static org.junit.Assert.assertFalse;
-import static org.junit.Assert.assertNotNull;
-import static org.junit.Assert.assertNull;
-import static org.junit.Assert.assertSame;
-import static org.junit.Assert.assertThat;
-import static org.junit.Assert.assertTrue;
+import static org.assertj.core.api.Assertions.assertThat;
 
 import java.util.ArrayList;
 import java.util.List;
@@ -31,7 +25,6 @@ import java.util.concurrent.TimeUnit;
 import java.util.concurrent.atomic.AtomicBoolean;
 import java.util.concurrent.atomic.AtomicInteger;
 
-import org.hamcrest.Matchers;
 import org.junit.Test;
 
 import org.springframework.context.ConfigurableApplicationContext;
@@ -67,10 +60,10 @@ public class ChannelInterceptorTests {
 		channel.addInterceptor(interceptor);
 		channel.send(new GenericMessage<String>("test"));
 		Message<?> result = channel.receive(0);
-		assertNotNull(result);
-		assertEquals("test", result.getPayload());
-		assertEquals(1, result.getHeaders().get(PreSendReturnsMessageInterceptor.class.getSimpleName()));
-		assertTrue(interceptor.wasAfterCompletionInvoked());
+		assertThat(result).isNotNull();
+		assertThat(result.getPayload()).isEqualTo("test");
+		assertThat(result.getHeaders().get(PreSendReturnsMessageInterceptor.class.getSimpleName())).isEqualTo(1);
+		assertThat(interceptor.wasAfterCompletionInvoked()).isTrue();
 	}
 
 	@Test
@@ -79,16 +72,16 @@ public class ChannelInterceptorTests {
 		channel.addInterceptor(interceptor);
 		Message<?> message = new GenericMessage<String>("test");
 		channel.send(message);
-		assertEquals(1, interceptor.getCount());
+		assertThat(interceptor.getCount()).isEqualTo(1);
 
-		assertTrue(channel.removeInterceptor(interceptor));
+		assertThat(channel.removeInterceptor(interceptor)).isTrue();
 
 		channel.send(new GenericMessage<String>("TEST"));
-		assertEquals(1, interceptor.getCount());
+		assertThat(interceptor.getCount()).isEqualTo(1);
 
 		Message<?> result = channel.receive(0);
-		assertNotNull(result);
-		assertEquals("TEST", result.getPayload());
+		assertThat(result).isNotNull();
+		assertThat(result.getPayload()).isEqualTo("TEST");
 	}
 
 	@Test
@@ -98,16 +91,16 @@ public class ChannelInterceptorTests {
 
 			@Override
 			public void postSend(Message<?> message, MessageChannel channel, boolean sent) {
-				assertNotNull(message);
-				assertNotNull(channel);
-				assertSame(ChannelInterceptorTests.this.channel, channel);
-				assertTrue(sent);
+				assertThat(message).isNotNull();
+				assertThat(channel).isNotNull();
+				assertThat(channel).isSameAs(ChannelInterceptorTests.this.channel);
+				assertThat(sent).isTrue();
 				invoked.set(true);
 			}
 
 		});
 		channel.send(new GenericMessage<String>("test"));
-		assertTrue(invoked.get());
+		assertThat(invoked.get()).isTrue();
 	}
 
 	@Test
@@ -119,9 +112,9 @@ public class ChannelInterceptorTests {
 
 			@Override
 			public void postSend(Message<?> message, MessageChannel channel, boolean sent) {
-				assertNotNull(message);
-				assertNotNull(channel);
-				assertSame(singleItemChannel, channel);
+				assertThat(message).isNotNull();
+				assertThat(channel).isNotNull();
+				assertThat(channel).isSameAs(singleItemChannel);
 				if (sent) {
 					sentCounter.incrementAndGet();
 				}
@@ -129,19 +122,19 @@ public class ChannelInterceptorTests {
 			}
 
 		});
-		assertEquals(0, invokedCounter.get());
-		assertEquals(0, sentCounter.get());
+		assertThat(invokedCounter.get()).isEqualTo(0);
+		assertThat(sentCounter.get()).isEqualTo(0);
 		singleItemChannel.send(new GenericMessage<String>("test1"));
-		assertEquals(1, invokedCounter.get());
-		assertEquals(1, sentCounter.get());
+		assertThat(invokedCounter.get()).isEqualTo(1);
+		assertThat(sentCounter.get()).isEqualTo(1);
 		singleItemChannel.send(new GenericMessage<String>("test2"), 0);
-		assertEquals(2, invokedCounter.get());
-		assertEquals(1, sentCounter.get());
+		assertThat(invokedCounter.get()).isEqualTo(2);
+		assertThat(sentCounter.get()).isEqualTo(1);
 
-		assertNotNull(singleItemChannel.removeInterceptor(0));
+		assertThat(singleItemChannel.removeInterceptor(0)).isNotNull();
 		singleItemChannel.send(new GenericMessage<String>("test2"), 0);
-		assertEquals(2, invokedCounter.get());
-		assertEquals(1, sentCounter.get());
+		assertThat(invokedCounter.get()).isEqualTo(2);
+		assertThat(sentCounter.get()).isEqualTo(1);
 	}
 
 	@Test
@@ -161,10 +154,10 @@ public class ChannelInterceptorTests {
 			testChannel.send(MessageBuilder.withPayload("test").build());
 		}
 		catch (Exception ex) {
-			assertEquals("Simulated exception", ex.getCause().getMessage());
+			assertThat(ex.getCause().getMessage()).isEqualTo("Simulated exception");
 		}
-		assertTrue(interceptor1.wasAfterCompletionInvoked());
-		assertTrue(interceptor2.wasAfterCompletionInvoked());
+		assertThat(interceptor1.wasAfterCompletionInvoked()).isTrue();
+		assertThat(interceptor2.wasAfterCompletionInvoked()).isTrue();
 	}
 
 	@Test
@@ -178,10 +171,10 @@ public class ChannelInterceptorTests {
 			this.channel.send(MessageBuilder.withPayload("test").build());
 		}
 		catch (Exception ex) {
-			assertEquals("Simulated exception", ex.getCause().getMessage());
+			assertThat(ex.getCause().getMessage()).isEqualTo("Simulated exception");
 		}
-		assertTrue(interceptor1.wasAfterCompletionInvoked());
-		assertFalse(interceptor2.wasAfterCompletionInvoked());
+		assertThat(interceptor1.wasAfterCompletionInvoked()).isTrue();
+		assertThat(interceptor2.wasAfterCompletionInvoked()).isFalse();
 	}
 
 	@Test
@@ -191,9 +184,9 @@ public class ChannelInterceptorTests {
 		Message<?> message = new GenericMessage<String>("test");
 		channel.send(message);
 		Message<?> result = channel.receive(0);
-		assertEquals(1, interceptor.getCounter().get());
-		assertNotNull(result);
-		assertTrue(interceptor.wasAfterCompletionInvoked());
+		assertThat(interceptor.getCounter().get()).isEqualTo(1);
+		assertThat(result).isNotNull();
+		assertThat(interceptor.wasAfterCompletionInvoked()).isTrue();
 	}
 
 	@Test
@@ -202,8 +195,8 @@ public class ChannelInterceptorTests {
 		Message<?> message = new GenericMessage<String>("test");
 		channel.send(message);
 		Message<?> result = channel.receive(0);
-		assertEquals(1, PreReceiveReturnsFalseInterceptor.counter.get());
-		assertNull(result);
+		assertThat(PreReceiveReturnsFalseInterceptor.counter.get()).isEqualTo(1);
+		assertThat(result).isNull();
 	}
 
 	@Test
@@ -213,19 +206,19 @@ public class ChannelInterceptorTests {
 
 			@Override
 			public Message<?> postReceive(Message<?> message, MessageChannel channel) {
-				assertNotNull(channel);
-				assertSame(ChannelInterceptorTests.this.channel, channel);
+				assertThat(channel).isNotNull();
+				assertThat(channel).isSameAs(ChannelInterceptorTests.this.channel);
 				messageCount.incrementAndGet();
 				return message;
 			}
 
 		});
 		channel.receive(0);
-		assertEquals(0, messageCount.get());
+		assertThat(messageCount.get()).isEqualTo(0);
 		channel.send(new GenericMessage<String>("test"));
 		Message<?> result = channel.receive(0);
-		assertNotNull(result);
-		assertEquals(1, messageCount.get());
+		assertThat(result).isNotNull();
+		assertThat(messageCount.get()).isEqualTo(1);
 	}
 
 	@Test
@@ -240,10 +233,10 @@ public class ChannelInterceptorTests {
 			channel.receive(0);
 		}
 		catch (Exception ex) {
-			assertEquals("Simulated exception", ex.getMessage());
+			assertThat(ex.getMessage()).isEqualTo("Simulated exception");
 		}
-		assertTrue(interceptor1.wasAfterCompletionInvoked());
-		assertFalse(interceptor2.wasAfterCompletionInvoked());
+		assertThat(interceptor1.wasAfterCompletionInvoked()).isTrue();
+		assertThat(interceptor2.wasAfterCompletionInvoked()).isFalse();
 	}
 
 	@Test
@@ -253,10 +246,10 @@ public class ChannelInterceptorTests {
 		ChannelInterceptorAware channel = ac.getBean("input", AbstractMessageChannel.class);
 		List<ChannelInterceptor> interceptors = channel.getChannelInterceptors();
 		ChannelInterceptor channelInterceptor = interceptors.get(0);
-		assertThat(channelInterceptor, Matchers.instanceOf(PreSendReturnsMessageInterceptor.class));
+		assertThat(channelInterceptor).isInstanceOf(PreSendReturnsMessageInterceptor.class);
 		String foo = ((PreSendReturnsMessageInterceptor) channelInterceptor).getFoo();
-		assertTrue(StringUtils.hasText(foo));
-		assertEquals("foo", foo);
+		assertThat(StringUtils.hasText(foo)).isTrue();
+		assertThat(foo).isEqualTo("foo");
 		ac.close();
 	}
 
@@ -281,16 +274,16 @@ public class ChannelInterceptorTests {
 
 		channel.send(new GenericMessage<>("foo"));
 
-		assertTrue(latch1.await(10, TimeUnit.SECONDS));
+		assertThat(latch1.await(10, TimeUnit.SECONDS)).isTrue();
 
 		channel.addInterceptor(new TestExecutorInterceptor());
 		channel.send(new GenericMessage<>("foo"));
 
-		assertTrue(latch2.await(10, TimeUnit.SECONDS));
-		assertEquals(2, messages.size());
+		assertThat(latch2.await(10, TimeUnit.SECONDS)).isTrue();
+		assertThat(messages.size()).isEqualTo(2);
 
-		assertEquals("foo", messages.get(0).getPayload());
-		assertEquals("FOO", messages.get(1).getPayload());
+		assertThat(messages.get(0).getPayload()).isEqualTo("foo");
+		assertThat(messages.get(1).getPayload()).isEqualTo("FOO");
 
 		testApplicationContext.close();
 	}
@@ -304,7 +297,7 @@ public class ChannelInterceptorTests {
 
 		@Override
 		public Message<?> preSend(Message<?> message, MessageChannel channel) {
-			assertNotNull(message);
+			assertThat(message).isNotNull();
 			return MessageBuilder.fromMessage(message)
 					.setHeader(this.getClass().getSimpleName(), counter.incrementAndGet())
 					.build();
@@ -343,7 +336,7 @@ public class ChannelInterceptorTests {
 
 		@Override
 		public Message<?> preSend(Message<?> message, MessageChannel channel) {
-			assertNotNull(message);
+			assertThat(message).isNotNull();
 			counter.incrementAndGet();
 			return null;
 		}
@@ -376,7 +369,7 @@ public class ChannelInterceptorTests {
 
 		@Override
 		public Message<?> preSend(Message<?> message, MessageChannel channel) {
-			assertNotNull(message);
+			assertThat(message).isNotNull();
 			counter.incrementAndGet();
 			if (this.exceptionToRaise != null) {
 				throw this.exceptionToRaise;

spring-integration-core/src/test/java/org/springframework/integration/channel/interceptor/GlobalChannelInterceptorSubElementTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2015 the original author or authors.
+ * Copyright 2002-2019 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -16,9 +16,7 @@
 
 package org.springframework.integration.channel.interceptor;
 
-import static org.junit.Assert.assertEquals;
-import static org.junit.Assert.assertNotNull;
-import static org.junit.Assert.assertNull;
+import static org.assertj.core.api.Assertions.assertThat;
 
 import org.junit.Test;
 import org.junit.runner.RunWith;
@@ -59,10 +57,10 @@ public class GlobalChannelInterceptorSubElementTests {
 	public void testWiretapSubElement() {
 		this.inputA.send(new GenericMessage<String>("hello"));
 		Message<?> result = this.wiretapChannel.receive(100);
-		assertNotNull(result);
-		assertEquals("hello", result.getPayload());
-		assertNull(this.wiretapChannel.receive(1));
-		assertNull(this.wiretap1.receive(1));
+		assertThat(result).isNotNull();
+		assertThat(result.getPayload()).isEqualTo("hello");
+		assertThat(this.wiretapChannel.receive(1)).isNull();
+		assertThat(this.wiretap1.receive(1)).isNull();
 	}
 
 }

spring-integration-core/src/test/java/org/springframework/integration/channel/interceptor/GlobalChannelInterceptorTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2018 the original author or authors.
+ * Copyright 2002-2019 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -16,11 +16,7 @@
 
 package org.springframework.integration.channel.interceptor;
 
-import static org.hamcrest.Matchers.instanceOf;
-import static org.junit.Assert.assertEquals;
-import static org.junit.Assert.assertNotNull;
-import static org.junit.Assert.assertThat;
-import static org.junit.Assert.assertTrue;
+import static org.assertj.core.api.Assertions.assertThat;
 
 import java.util.ArrayList;
 import java.util.List;
@@ -76,60 +72,60 @@ public class GlobalChannelInterceptorTests {
 			ChannelInterceptor[] interceptors = channel.getChannelInterceptors()
 					.toArray(new ChannelInterceptor[channel.getChannelInterceptors().size()]);
 			if (channelName.equals("inputA")) { // 328741
-				assertTrue(interceptors.length == 10);
-				assertEquals("interceptor-three", interceptors[0].toString());
-				assertEquals("interceptor-two", interceptors[1].toString());
-				assertEquals("interceptor-eight", interceptors[2].toString());
-				assertEquals("interceptor-seven", interceptors[3].toString());
-				assertEquals("interceptor-five", interceptors[4].toString());
-				assertEquals("interceptor-six", interceptors[5].toString());
-				assertEquals("interceptor-ten", interceptors[6].toString());
-				assertEquals("interceptor-eleven", interceptors[7].toString());
-				assertEquals("interceptor-four", interceptors[8].toString());
-				assertEquals("interceptor-one", interceptors[9].toString());
+				assertThat(interceptors.length == 10).isTrue();
+				assertThat(interceptors[0].toString()).isEqualTo("interceptor-three");
+				assertThat(interceptors[1].toString()).isEqualTo("interceptor-two");
+				assertThat(interceptors[2].toString()).isEqualTo("interceptor-eight");
+				assertThat(interceptors[3].toString()).isEqualTo("interceptor-seven");
+				assertThat(interceptors[4].toString()).isEqualTo("interceptor-five");
+				assertThat(interceptors[5].toString()).isEqualTo("interceptor-six");
+				assertThat(interceptors[6].toString()).isEqualTo("interceptor-ten");
+				assertThat(interceptors[7].toString()).isEqualTo("interceptor-eleven");
+				assertThat(interceptors[8].toString()).isEqualTo("interceptor-four");
+				assertThat(interceptors[9].toString()).isEqualTo("interceptor-one");
 			}
 			else if (channelName.equals("inputB")) {
-				assertTrue(interceptors.length == 6);
-				assertEquals("interceptor-three", interceptors[0].toString());
-				assertEquals("interceptor-two", interceptors[1].toString());
-				assertEquals("interceptor-ten", interceptors[2].toString());
-				assertEquals("interceptor-eleven", interceptors[3].toString());
-				assertEquals("interceptor-four", interceptors[4].toString());
-				assertEquals("interceptor-one", interceptors[5].toString());
+				assertThat(interceptors.length == 6).isTrue();
+				assertThat(interceptors[0].toString()).isEqualTo("interceptor-three");
+				assertThat(interceptors[1].toString()).isEqualTo("interceptor-two");
+				assertThat(interceptors[2].toString()).isEqualTo("interceptor-ten");
+				assertThat(interceptors[3].toString()).isEqualTo("interceptor-eleven");
+				assertThat(interceptors[4].toString()).isEqualTo("interceptor-four");
+				assertThat(interceptors[5].toString()).isEqualTo("interceptor-one");
 			}
 			else if (channelName.equals("foo")) {
-				assertTrue(interceptors.length == 6);
-				assertEquals("interceptor-two", interceptors[0].toString());
-				assertEquals("interceptor-five", interceptors[1].toString());
-				assertEquals("interceptor-ten", interceptors[2].toString());
-				assertEquals("interceptor-eleven", interceptors[3].toString());
-				assertEquals("interceptor-four", interceptors[4].toString());
-				assertEquals("interceptor-one", interceptors[5].toString());
+				assertThat(interceptors.length == 6).isTrue();
+				assertThat(interceptors[0].toString()).isEqualTo("interceptor-two");
+				assertThat(interceptors[1].toString()).isEqualTo("interceptor-five");
+				assertThat(interceptors[2].toString()).isEqualTo("interceptor-ten");
+				assertThat(interceptors[3].toString()).isEqualTo("interceptor-eleven");
+				assertThat(interceptors[4].toString()).isEqualTo("interceptor-four");
+				assertThat(interceptors[5].toString()).isEqualTo("interceptor-one");
 			}
 			else if (channelName.equals("bar")) {
-				assertTrue(interceptors.length == 4);
-				assertEquals("interceptor-eight", interceptors[0].toString());
-				assertEquals("interceptor-seven", interceptors[1].toString());
-				assertEquals("interceptor-ten", interceptors[2].toString());
-				assertEquals("interceptor-eleven", interceptors[3].toString());
+				assertThat(interceptors.length == 4).isTrue();
+				assertThat(interceptors[0].toString()).isEqualTo("interceptor-eight");
+				assertThat(interceptors[1].toString()).isEqualTo("interceptor-seven");
+				assertThat(interceptors[2].toString()).isEqualTo("interceptor-ten");
+				assertThat(interceptors[3].toString()).isEqualTo("interceptor-eleven");
 			}
 			else if (channelName.equals("baz")) {
-				assertTrue(interceptors.length == 2);
-				assertEquals("interceptor-ten", interceptors[0].toString());
-				assertEquals("interceptor-eleven", interceptors[1].toString());
+				assertThat(interceptors.length == 2).isTrue();
+				assertThat(interceptors[0].toString()).isEqualTo("interceptor-ten");
+				assertThat(interceptors[1].toString()).isEqualTo("interceptor-eleven");
 			}
 			else if (channelName.equals("inputWithProxy")) {
-				assertTrue(interceptors.length == 6);
+				assertThat(interceptors.length == 6).isTrue();
 			}
 			else if (channelName.equals("test")) {
-				assertNotNull(interceptors);
-				assertTrue(interceptors.length == 2);
+				assertThat(interceptors).isNotNull();
+				assertThat(interceptors.length == 2).isTrue();
 				List<String> interceptorNames = new ArrayList<String>();
 				for (ChannelInterceptor interceptor : interceptors) {
 					interceptorNames.add(interceptor.toString());
 				}
-				assertTrue(interceptorNames.contains("interceptor-ten"));
-				assertTrue(interceptorNames.contains("interceptor-eleven"));
+				assertThat(interceptorNames.contains("interceptor-ten")).isTrue();
+				assertThat(interceptorNames.contains("interceptor-eleven")).isTrue();
 			}
 		}
 	}
@@ -142,8 +138,8 @@ public class GlobalChannelInterceptorTests {
 		for (ChannelInterceptor interceptor : channelInterceptors) {
 			interceptorNames.add(interceptor.toString());
 		}
-		assertTrue(interceptorNames.contains("interceptor-ten"));
-		assertTrue(interceptorNames.contains("interceptor-eleven"));
+		assertThat(interceptorNames.contains("interceptor-ten")).isTrue();
+		assertThat(interceptorNames.contains("interceptor-eleven")).isTrue();
 	}
 
 	@Test
@@ -154,9 +150,9 @@ public class GlobalChannelInterceptorTests {
 
 		List<ChannelInterceptor> channelInterceptors = testChannel.getChannelInterceptors();
 
-		assertEquals(2, channelInterceptors.size());
-		assertThat(channelInterceptors.get(0), instanceOf(SampleInterceptor.class));
-		assertThat(channelInterceptors.get(0), instanceOf(SampleInterceptor.class));
+		assertThat(channelInterceptors.size()).isEqualTo(2);
+		assertThat(channelInterceptors.get(0)).isInstanceOf(SampleInterceptor.class);
+		assertThat(channelInterceptors.get(0)).isInstanceOf(SampleInterceptor.class);
 	}
 
 	public static class SampleInterceptor implements ChannelInterceptor {

spring-integration-core/src/test/java/org/springframework/integration/channel/interceptor/GlobalWireTapTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2016 the original author or authors.
+ * Copyright 2002-2019 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -16,9 +16,7 @@
 
 package org.springframework.integration.channel.interceptor;
 
-import static org.junit.Assert.assertEquals;
-import static org.junit.Assert.assertNotNull;
-import static org.junit.Assert.assertNull;
+import static org.assertj.core.api.Assertions.assertThat;
 
 import org.junit.Test;
 import org.junit.runner.RunWith;
@@ -73,7 +71,7 @@ public class GlobalWireTapTests {
 		Message<?> message = new GenericMessage<String>("hello");
 		this.channel.send(message);
 		Message<?> wireTapMessage = this.wiretapSingle.receive(100);
-		assertNotNull(wireTapMessage);
+		assertThat(wireTapMessage).isNotNull();
 
 		// There should be 5 messages on this channel:
 		// 'channel', 'output', 'wiretapSingle', and too for 'unnamedGlobalWireTaps'.
@@ -81,15 +79,15 @@ public class GlobalWireTapTests {
 		int msgCount = 0;
 		while (wireTapMessage != null) {
 			msgCount++;
-			assertEquals(wireTapMessage.getPayload(), message.getPayload());
+			assertThat(message.getPayload()).isEqualTo(wireTapMessage.getPayload());
 			wireTapMessage = this.wiretapAll.receive(100);
 		}
 
-		assertEquals(5, msgCount);
+		assertThat(msgCount).isEqualTo(5);
 
-		assertNull(this.wiretapAll2.receive(1));
+		assertThat(this.wiretapAll2.receive(1)).isNull();
 
-		assertEquals(4, this.channel.getChannelInterceptors().size());
+		assertThat(this.channel.getChannelInterceptors().size()).isEqualTo(4);
 	}
 
 	@Test
@@ -99,18 +97,18 @@ public class GlobalWireTapTests {
 
 		//This time no message on wiretapSingle
 		Message<?> wireTapMessage = wiretapSingle.receive(100);
-		assertNull(wireTapMessage);
+		assertThat(wireTapMessage).isNull();
 
 		//There should be two messages on this channel. One for 'channel' and one for 'output'
 		wireTapMessage = wiretapAll.receive(100);
 		int msgCount = 0;
 		while (wireTapMessage != null) {
 			msgCount++;
-			assertEquals(wireTapMessage.getPayload(), message.getPayload());
+			assertThat(message.getPayload()).isEqualTo(wireTapMessage.getPayload());
 			wireTapMessage = wiretapAll.receive(100);
 		}
 
-		assertEquals(2, msgCount);
+		assertThat(msgCount).isEqualTo(2);
 	}
 
 }

spring-integration-core/src/test/java/org/springframework/integration/channel/interceptor/ImplicitConsumerChannelTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2014-2018 the original author or authors.
+ * Copyright 2014-2019 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -16,10 +16,7 @@
 
 package org.springframework.integration.channel.interceptor;
 
-import static org.hamcrest.Matchers.anyOf;
-import static org.hamcrest.Matchers.instanceOf;
-import static org.junit.Assert.assertEquals;
-import static org.junit.Assert.assertThat;
+import static org.assertj.core.api.Assertions.assertThat;
 
 import java.util.List;
 
@@ -57,17 +54,17 @@ public class ImplicitConsumerChannelTests {
 	public void testImplicit() {
 		// used to fail to load AC (no channel 'bar')
 		List<ChannelInterceptor> barInterceptors = bar.getChannelInterceptors();
-		assertEquals(2, barInterceptors.size());
-		assertThat(barInterceptors.get(0), anyOf(instanceOf(Interceptor1.class), instanceOf(Interceptor2.class)));
-		assertThat(barInterceptors.get(1), anyOf(instanceOf(Interceptor1.class), instanceOf(Interceptor2.class)));
+		assertThat(barInterceptors.size()).isEqualTo(2);
+		assertThat(barInterceptors.get(0)).isInstanceOfAny(Interceptor1.class, Interceptor2.class);
+		assertThat(barInterceptors.get(1)).isInstanceOfAny(Interceptor1.class, Interceptor2.class);
 		List<ChannelInterceptor> fooInterceptors = foo.getChannelInterceptors();
-		assertEquals(2, fooInterceptors.size());
-		assertThat(fooInterceptors.get(0), anyOf(instanceOf(WireTap.class), instanceOf(Interceptor2.class)));
-		assertThat(fooInterceptors.get(1), anyOf(instanceOf(WireTap.class), instanceOf(Interceptor2.class)));
+		assertThat(fooInterceptors.size()).isEqualTo(2);
+		assertThat(fooInterceptors.get(0)).isInstanceOfAny(WireTap.class, Interceptor2.class);
+		assertThat(fooInterceptors.get(1)).isInstanceOfAny(WireTap.class, Interceptor2.class);
 		List<ChannelInterceptor> bazInterceptors = baz.getChannelInterceptors();
-		assertEquals(2, bazInterceptors.size());
-		assertThat(bazInterceptors.get(0), anyOf(instanceOf(WireTap.class), instanceOf(Interceptor1.class)));
-		assertThat(bazInterceptors.get(1), anyOf(instanceOf(WireTap.class), instanceOf(Interceptor1.class)));
+		assertThat(bazInterceptors.size()).isEqualTo(2);
+		assertThat(bazInterceptors.get(0)).isInstanceOfAny(WireTap.class, Interceptor1.class);
+		assertThat(bazInterceptors.get(1)).isInstanceOfAny(WireTap.class, Interceptor1.class);
 	}
 
 	public static class Interceptor1 implements ChannelInterceptor, VetoCapableInterceptor {

spring-integration-core/src/test/java/org/springframework/integration/channel/interceptor/MessageSelectingInterceptorTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2018 the original author or authors.
+ * Copyright 2002-2019 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -16,8 +16,7 @@
 
 package org.springframework.integration.channel.interceptor;
 
-import static org.junit.Assert.assertEquals;
-import static org.junit.Assert.assertTrue;
+import static org.assertj.core.api.Assertions.assertThat;
 
 import java.util.concurrent.atomic.AtomicInteger;
 
@@ -42,7 +41,7 @@ public class MessageSelectingInterceptorTests {
 		MessageSelectingInterceptor interceptor = new MessageSelectingInterceptor(selector);
 		QueueChannel channel = new QueueChannel();
 		channel.addInterceptor(interceptor);
-		assertTrue(channel.send(new GenericMessage<>("test1")));
+		assertThat(channel.send(new GenericMessage<>("test1"))).isTrue();
 	}
 
 	@Test(expected = MessageDeliveryException.class)
@@ -63,8 +62,8 @@ public class MessageSelectingInterceptorTests {
 		MessageSelectingInterceptor interceptor = new MessageSelectingInterceptor(selector1, selector2);
 		QueueChannel channel = new QueueChannel();
 		channel.addInterceptor(interceptor);
-		assertTrue(channel.send(new GenericMessage<>("test1")));
-		assertEquals(2, counter.get());
+		assertThat(channel.send(new GenericMessage<>("test1"))).isTrue();
+		assertThat(counter.get()).isEqualTo(2);
 	}
 
 	@Test
@@ -85,8 +84,8 @@ public class MessageSelectingInterceptorTests {
 		catch (MessageDeliveryException e) {
 			exceptionThrown = true;
 		}
-		assertTrue(exceptionThrown);
-		assertEquals(2, counter.get());
+		assertThat(exceptionThrown).isTrue();
+		assertThat(counter.get()).isEqualTo(2);
 	}
 
 

spring-integration-core/src/test/java/org/springframework/integration/channel/interceptor/WireTapTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2018 the original author or authors.
+ * Copyright 2002-2019 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -16,9 +16,7 @@
 
 package org.springframework.integration.channel.interceptor;
 
-import static org.junit.Assert.assertEquals;
-import static org.junit.Assert.assertNotNull;
-import static org.junit.Assert.assertNull;
+import static org.assertj.core.api.Assertions.assertThat;
 
 import org.junit.Test;
 
@@ -42,10 +40,10 @@ public class WireTapTests {
 		mainChannel.addInterceptor(new WireTap(secondaryChannel));
 		mainChannel.send(new GenericMessage<>("testing"));
 		Message<?> original = mainChannel.receive(0);
-		assertNotNull(original);
+		assertThat(original).isNotNull();
 		Message<?> intercepted = secondaryChannel.receive(0);
-		assertNotNull(intercepted);
-		assertEquals(original, intercepted);
+		assertThat(intercepted).isNotNull();
+		assertThat(intercepted).isEqualTo(original);
 	}
 
 	@Test
@@ -55,9 +53,9 @@ public class WireTapTests {
 		mainChannel.addInterceptor(new WireTap(secondaryChannel, new TestSelector(false)));
 		mainChannel.send(new GenericMessage<>("testing"));
 		Message<?> original = mainChannel.receive(0);
-		assertNotNull(original);
+		assertThat(original).isNotNull();
 		Message<?> intercepted = secondaryChannel.receive(0);
-		assertNull(intercepted);
+		assertThat(intercepted).isNull();
 	}
 
 	@Test
@@ -67,10 +65,10 @@ public class WireTapTests {
 		mainChannel.addInterceptor(new WireTap(secondaryChannel, new TestSelector(true)));
 		mainChannel.send(new GenericMessage<>("testing"));
 		Message<?> original = mainChannel.receive(0);
-		assertNotNull(original);
+		assertThat(original).isNotNull();
 		Message<?> intercepted = secondaryChannel.receive(0);
-		assertNotNull(intercepted);
-		assertEquals(original, intercepted);
+		assertThat(intercepted).isNotNull();
+		assertThat(intercepted).isEqualTo(original);
 	}
 
 	@Test(expected = IllegalArgumentException.class)
@@ -83,14 +81,14 @@ public class WireTapTests {
 		QueueChannel mainChannel = new QueueChannel();
 		QueueChannel secondaryChannel = new QueueChannel();
 		mainChannel.addInterceptor(new WireTap(secondaryChannel));
-		assertNull(secondaryChannel.receive(0));
+		assertThat(secondaryChannel.receive(0)).isNull();
 		Message<?> message = new GenericMessage<>("testing");
 		mainChannel.send(message);
 		Message<?> original = mainChannel.receive(0);
 		Message<?> intercepted = secondaryChannel.receive(0);
-		assertNotNull(original);
-		assertNotNull(intercepted);
-		assertEquals(original, intercepted);
+		assertThat(original).isNotNull();
+		assertThat(intercepted).isNotNull();
+		assertThat(intercepted).isEqualTo(original);
 	}
 
 	@Test
@@ -106,9 +104,9 @@ public class WireTapTests {
 		Message<?> intercepted = secondaryChannel.receive(0);
 		Object originalAttribute = original.getHeaders().get(headerName);
 		Object interceptedAttribute = intercepted.getHeaders().get(headerName);
-		assertNotNull(originalAttribute);
-		assertNotNull(interceptedAttribute);
-		assertEquals(originalAttribute, interceptedAttribute);
+		assertThat(originalAttribute).isNotNull();
+		assertThat(interceptedAttribute).isNotNull();
+		assertThat(interceptedAttribute).isEqualTo(originalAttribute);
 	}
 
 	@Test

spring-integration-core/src/test/java/org/springframework/integration/channel/reactive/FluxMessageChannelTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2016-2018 the original author or authors.
+ * Copyright 2016-2019 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -16,13 +16,7 @@
 
 package org.springframework.integration.channel.reactive;
 
-import static org.hamcrest.Matchers.contains;
-import static org.hamcrest.Matchers.isOneOf;
-import static org.junit.Assert.assertEquals;
-import static org.junit.Assert.assertNotNull;
-import static org.junit.Assert.assertNull;
-import static org.junit.Assert.assertThat;
-import static org.junit.Assert.assertTrue;
+import static org.assertj.core.api.Assertions.assertThat;
 
 import java.util.ArrayList;
 import java.util.List;
@@ -88,14 +82,14 @@ public class FluxMessageChannelTests {
 
 		for (int i = 0; i < 9; i++) {
 			Message<?> receive = replyChannel.receive(10000);
-			assertNotNull(receive);
-			assertThat(receive.getPayload(), isOneOf("0", "1", "2", "3", "4", "6", "7", "8", "9"));
+			assertThat(receive).isNotNull();
+			assertThat(receive.getPayload()).isIn("0", "1", "2", "3", "4", "6", "7", "8", "9");
 		}
-		assertNull(replyChannel.receive(0));
+		assertThat(replyChannel.receive(0)).isNull();
 
 		Message<?> error = this.errorChannel.receive(0);
-		assertNotNull(error);
-		assertEquals(5, ((MessagingException) error.getPayload()).getFailedMessage().getPayload());
+		assertThat(error).isNotNull();
+		assertThat(((MessagingException) error.getPayload()).getFailedMessage().getPayload()).isEqualTo(5);
 	}
 
 	@Test
@@ -112,8 +106,8 @@ public class FluxMessageChannelTests {
 		this.queueChannel.send(new GenericMessage<>("foo"));
 		this.queueChannel.send(new GenericMessage<>("bar"));
 
-		assertTrue(done.await(10, TimeUnit.SECONDS));
-		assertThat(results, contains("FOO", "BAR"));
+		assertThat(done.await(10, TimeUnit.SECONDS)).isTrue();
+		assertThat(results).containsExactly("FOO", "BAR");
 	}
 
 	@Test
@@ -134,9 +128,9 @@ public class FluxMessageChannelTests {
 
 		flowRegistration.getInputChannel().send(new GenericMessage<>("foo"));
 
-		assertTrue(finishLatch.await(10, TimeUnit.SECONDS));
+		assertThat(finishLatch.await(10, TimeUnit.SECONDS)).isTrue();
 
-		assertTrue(TestUtils.getPropertyValue(flux, "publishers", Map.class).isEmpty());
+		assertThat(TestUtils.getPropertyValue(flux, "publishers", Map.class).isEmpty()).isTrue();
 
 		flowRegistration.destroy();
 	}

spring-integration-core/src/test/java/org/springframework/integration/channel/reactive/ReactiveStreamsConsumerTests.java

@@ -16,13 +16,8 @@
 
 package org.springframework.integration.channel.reactive;
 
-import static org.hamcrest.Matchers.containsString;
-import static org.hamcrest.Matchers.equalTo;
-import static org.hamcrest.Matchers.instanceOf;
-import static org.junit.Assert.assertSame;
-import static org.junit.Assert.assertThat;
-import static org.junit.Assert.assertTrue;
-import static org.junit.Assert.fail;
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.assertj.core.api.Assertions.fail;
 import static org.mockito.ArgumentMatchers.any;
 import static org.mockito.BDDMockito.willAnswer;
 import static org.mockito.Mockito.mock;
@@ -37,7 +32,6 @@ import java.util.concurrent.CountDownLatch;
 import java.util.concurrent.LinkedBlockingQueue;
 import java.util.concurrent.TimeUnit;
 
-import org.hamcrest.Matchers;
 import org.junit.Test;
 import org.mockito.ArgumentCaptor;
 import org.mockito.Mockito;
@@ -92,9 +86,9 @@ public class ReactiveStreamsConsumerTests {
 			testChannel.send(testMessage);
 		}
 		catch (Exception e) {
-			assertThat(e, instanceOf(MessageDeliveryException.class));
-			assertThat(e.getCause(), instanceOf(IllegalStateException.class));
-			assertThat(e.getMessage(), containsString("doesn't have subscribers to accept messages"));
+			assertThat(e).isInstanceOf(MessageDeliveryException.class);
+			assertThat(e.getCause()).isInstanceOf(IllegalStateException.class);
+			assertThat(e.getMessage()).contains("doesn't have subscribers to accept messages");
 		}
 
 		reactiveConsumer.start();
@@ -102,8 +96,8 @@ public class ReactiveStreamsConsumerTests {
 		Message<?> testMessage2 = new GenericMessage<>("test2");
 		testChannel.send(testMessage2);
 
-		assertTrue(stopLatch.await(10, TimeUnit.SECONDS));
-		assertThat(result, Matchers.<Message<?>>contains(testMessage, testMessage2));
+		assertThat(stopLatch.await(10, TimeUnit.SECONDS)).isTrue();
+		assertThat(result).containsExactly(testMessage, testMessage2);
 	}
 
 
@@ -138,7 +132,7 @@ public class ReactiveStreamsConsumerTests {
 		subscription.request(1);
 
 		Message<?> message = messages.poll(10, TimeUnit.SECONDS);
-		assertSame(testMessage, message);
+		assertThat(message).isSameAs(testMessage);
 
 		reactiveConsumer.stop();
 
@@ -147,7 +141,7 @@ public class ReactiveStreamsConsumerTests {
 			fail("MessageDeliveryException");
 		}
 		catch (Exception e) {
-			assertThat(e, instanceOf(MessageDeliveryException.class));
+			assertThat(e).isInstanceOf(MessageDeliveryException.class);
 		}
 
 		reactiveConsumer.start();
@@ -159,12 +153,12 @@ public class ReactiveStreamsConsumerTests {
 		testChannel.send(testMessage);
 
 		message = messages.poll(10, TimeUnit.SECONDS);
-		assertSame(testMessage, message);
+		assertThat(message).isSameAs(testMessage);
 
 		verify(testSubscriber, never()).onError(any(Throwable.class));
 		verify(testSubscriber, never()).onComplete();
 
-		assertTrue(messages.isEmpty());
+		assertThat(messages.isEmpty()).isTrue();
 	}
 
 	@Test
@@ -198,7 +192,7 @@ public class ReactiveStreamsConsumerTests {
 		subscription.request(1);
 
 		Message<?> message = messages.poll(10, TimeUnit.SECONDS);
-		assertSame(testMessage, message);
+		assertThat(message).isSameAs(testMessage);
 
 		reactiveConsumer.stop();
 
@@ -217,15 +211,15 @@ public class ReactiveStreamsConsumerTests {
 		testChannel.send(testMessage2);
 
 		message = messages.poll(10, TimeUnit.SECONDS);
-		assertSame(testMessage, message);
+		assertThat(message).isSameAs(testMessage);
 
 		message = messages.poll(10, TimeUnit.SECONDS);
-		assertSame(testMessage2, message);
+		assertThat(message).isSameAs(testMessage2);
 
 		verify(testSubscriber, never()).onError(any(Throwable.class));
 		verify(testSubscriber, never()).onComplete();
 
-		assertTrue(messages.isEmpty());
+		assertThat(messages.isEmpty()).isTrue();
 	}
 
 	@Test
@@ -257,9 +251,9 @@ public class ReactiveStreamsConsumerTests {
 			testChannel.send(testMessage);
 		}
 		catch (Exception e) {
-			assertThat(e, instanceOf(MessageDeliveryException.class));
-			assertThat(e.getCause(), instanceOf(IllegalStateException.class));
-			assertThat(e.getMessage(), containsString("doesn't have subscribers to accept messages"));
+			assertThat(e).isInstanceOf(MessageDeliveryException.class);
+			assertThat(e.getCause()).isInstanceOf(IllegalStateException.class);
+			assertThat(e.getMessage()).contains("doesn't have subscribers to accept messages");
 		}
 
 		endpointFactoryBean.start();
@@ -269,9 +263,9 @@ public class ReactiveStreamsConsumerTests {
 		testChannel.send(testMessage2);
 		testChannel.send(testMessage2);
 
-		assertTrue(stopLatch.await(10, TimeUnit.SECONDS));
-		assertThat(result.size(), equalTo(3));
-		assertThat(result, Matchers.<Message<?>>contains(testMessage, testMessage2, testMessage2));
+		assertThat(stopLatch.await(10, TimeUnit.SECONDS)).isTrue();
+		assertThat(result.size()).isEqualTo(3);
+		assertThat(result).containsExactly(testMessage, testMessage2, testMessage2);
 	}
 
 }

spring-integration-core/src/test/java/org/springframework/integration/channel/registry/HeaderChannelRegistryTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2013-2017 the original author or authors.
+ * Copyright 2013-2019 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -16,25 +16,14 @@
 
 package org.springframework.integration.channel.registry;
 
-import static org.hamcrest.CoreMatchers.not;
-import static org.hamcrest.Matchers.allOf;
-import static org.hamcrest.Matchers.greaterThan;
-import static org.hamcrest.Matchers.instanceOf;
-import static org.hamcrest.Matchers.lessThan;
-import static org.junit.Assert.assertEquals;
-import static org.junit.Assert.assertNotNull;
-import static org.junit.Assert.assertNull;
-import static org.junit.Assert.assertSame;
-import static org.junit.Assert.assertThat;
-import static org.junit.Assert.assertTrue;
-import static org.junit.Assert.fail;
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.assertj.core.api.Assertions.fail;
 import static org.mockito.Mockito.doAnswer;
 import static org.mockito.Mockito.mock;
 import static org.mockito.Mockito.when;
 
 import java.util.Map;
 
-import org.hamcrest.Matchers;
 import org.junit.Test;
 import org.junit.runner.RunWith;
 
@@ -65,6 +54,8 @@ import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;
 
 /**
  * @author Gary Russell
+ * @author Artem Bilan
+ *
  * @since 3.0
  *
  */
@@ -105,13 +96,13 @@ public class HeaderChannelRegistryTests {
 		MessagingTemplate template = new MessagingTemplate();
 		template.setDefaultDestination(this.input);
 		Message<?> reply = template.sendAndReceive(new GenericMessage<String>("foo"));
-		assertNotNull(reply);
-		assertEquals("echo:foo", reply.getPayload());
+		assertThat(reply).isNotNull();
+		assertThat(reply.getPayload()).isEqualTo("echo:foo");
 		String stringReplyChannel = reply.getHeaders().get("stringReplyChannel", String.class);
 		assertThat(TestUtils.getPropertyValue(
 				TestUtils.getPropertyValue(registry, "channels", Map.class)
-					.get(stringReplyChannel), "expireAt", Long.class) - System.currentTimeMillis(),
-						lessThan(61000L));
+						.get(stringReplyChannel), "expireAt", Long.class) - System.currentTimeMillis())
+				.isLessThan(61000L);
 	}
 
 	@Test
@@ -119,13 +110,13 @@ public class HeaderChannelRegistryTests {
 		MessagingTemplate template = new MessagingTemplate();
 		template.setDefaultDestination(this.inputTtl);
 		Message<?> reply = template.sendAndReceive(new GenericMessage<String>("ttl"));
-		assertNotNull(reply);
-		assertEquals("echo:ttl", reply.getPayload());
+		assertThat(reply).isNotNull();
+		assertThat(reply.getPayload()).isEqualTo("echo:ttl");
 		String stringReplyChannel = reply.getHeaders().get("stringReplyChannel", String.class);
 		assertThat(TestUtils.getPropertyValue(
 				TestUtils.getPropertyValue(registry, "channels", Map.class)
-					.get(stringReplyChannel), "expireAt", Long.class) - System.currentTimeMillis(),
-						greaterThan(100000L));
+						.get(stringReplyChannel), "expireAt", Long.class) - System.currentTimeMillis())
+				.isGreaterThan(100000L);
 	}
 
 	@Test
@@ -136,36 +127,36 @@ public class HeaderChannelRegistryTests {
 				.setHeader("channelTTL", 180000)
 				.build();
 		Message<?> reply = template.sendAndReceive(requestMessage);
-		assertNotNull(reply);
-		assertEquals("echo:ttl", reply.getPayload());
+		assertThat(reply).isNotNull();
+		assertThat(reply.getPayload()).isEqualTo("echo:ttl");
 		String stringReplyChannel = reply.getHeaders().get("stringReplyChannel", String.class);
 		assertThat(TestUtils.getPropertyValue(
 				TestUtils.getPropertyValue(registry, "channels", Map.class)
-					.get(stringReplyChannel), "expireAt", Long.class) - System.currentTimeMillis(),
-						allOf(greaterThan(160000L), lessThan(181000L)));
+						.get(stringReplyChannel), "expireAt", Long.class) - System.currentTimeMillis())
+				.isGreaterThan(160000L).isLessThan(181000L);
 		// Now for Elvis...
 		reply = template.sendAndReceive(new GenericMessage<String>("ttl"));
-		assertNotNull(reply);
-		assertEquals("echo:ttl", reply.getPayload());
+		assertThat(reply).isNotNull();
+		assertThat(reply.getPayload()).isEqualTo("echo:ttl");
 		stringReplyChannel = reply.getHeaders().get("stringReplyChannel", String.class);
 		assertThat(TestUtils.getPropertyValue(
 				TestUtils.getPropertyValue(registry, "channels", Map.class)
-					.get(stringReplyChannel), "expireAt", Long.class) - System.currentTimeMillis(),
-						greaterThan(220000L));
+						.get(stringReplyChannel), "expireAt", Long.class) - System.currentTimeMillis())
+				.isGreaterThan(220000L);
 	}
 
 	@Test
 	public void testReplaceGatewayWithNoReplyChannel() {
 		String reply = this.gatewayNoReplyChannel.exchange("foo");
-		assertNotNull(reply);
-		assertEquals("echo:foo", reply);
+		assertThat(reply).isNotNull();
+		assertThat(reply).isEqualTo("echo:foo");
 	}
 
 	@Test
 	public void testReplaceGatewayWithExplicitReplyChannel() {
 		String reply = this.gatewayExplicitReplyChannel.exchange("foo");
-		assertNotNull(reply);
-		assertEquals("echo:foo", reply);
+		assertThat(reply).isNotNull();
+		assertThat(reply).isEqualTo("echo:foo");
 	}
 
 	/**
@@ -177,10 +168,10 @@ public class HeaderChannelRegistryTests {
 		MessagingTemplate template = new MessagingTemplate();
 		template.setDefaultDestination(this.inputPolled);
 		Message<?> reply = template.sendAndReceive(new GenericMessage<String>("bar"));
-		assertNotNull(reply);
-		assertTrue(reply instanceof ErrorMessage);
-		assertNotNull(((ErrorMessage) reply).getOriginalMessage());
-		assertThat(reply.getPayload(), not(instanceOf(MessagingExceptionWrapper.class)));
+		assertThat(reply).isNotNull();
+		assertThat(reply instanceof ErrorMessage).isTrue();
+		assertThat(((ErrorMessage) reply).getOriginalMessage()).isNotNull();
+		assertThat(reply.getPayload()).isNotInstanceOf(MessagingExceptionWrapper.class);
 	}
 
 	@Test
@@ -191,8 +182,8 @@ public class HeaderChannelRegistryTests {
 				.build();
 		this.input.send(requestMessage);
 		Message<?> reply = alreadyAString.receive(0);
-		assertNotNull(reply);
-		assertEquals("echo:foo", reply.getPayload());
+		assertThat(reply).isNotNull();
+		assertThat(reply.getPayload()).isEqualTo("echo:foo");
 	}
 
 	@Test
@@ -204,7 +195,7 @@ public class HeaderChannelRegistryTests {
 			fail("expected exception");
 		}
 		catch (Exception e) {
-			assertThat(e.getMessage(), Matchers.containsString("no output-channel or replyChannel"));
+			assertThat(e.getMessage()).contains("no output-channel or replyChannel");
 		}
 	}
 
@@ -217,7 +208,7 @@ public class HeaderChannelRegistryTests {
 		while (n++ < 100 && registry.channelNameToChannel(id) != null) {
 			Thread.sleep(100);
 		}
-		assertNull(registry.channelNameToChannel(id));
+		assertThat(registry.channelNameToChannel(id)).isNull();
 		registry.stop();
 	}
 
@@ -226,8 +217,8 @@ public class HeaderChannelRegistryTests {
 		BeanFactoryChannelResolver resolver = new BeanFactoryChannelResolver();
 		BeanFactory beanFactory = mock(BeanFactory.class);
 		when(beanFactory.getBean(IntegrationContextUtils.INTEGRATION_HEADER_CHANNEL_REGISTRY_BEAN_NAME,
-						HeaderChannelRegistry.class))
-			.thenReturn(mock(HeaderChannelRegistry.class));
+				HeaderChannelRegistry.class))
+				.thenReturn(mock(HeaderChannelRegistry.class));
 		doAnswer(invocation -> {
 			throw new NoSuchBeanDefinitionException("bar");
 		}).when(beanFactory).getBean("foo", MessageChannel.class);
@@ -237,8 +228,8 @@ public class HeaderChannelRegistryTests {
 			fail("Expected exception");
 		}
 		catch (DestinationResolutionException e) {
-			assertThat(e.getMessage(),
-				Matchers.containsString("failed to look up MessageChannel with name 'foo' in the BeanFactory."));
+			assertThat(e.getMessage()).contains("failed to look up MessageChannel with name 'foo' in the BeanFactory" +
+					".");
 		}
 	}
 
@@ -255,9 +246,9 @@ public class HeaderChannelRegistryTests {
 			fail("Expected exception");
 		}
 		catch (DestinationResolutionException e) {
-			assertThat(e.getMessage(),
-				Matchers.containsString("failed to look up MessageChannel with name 'foo' in the BeanFactory " +
-						"(and there is no HeaderChannelRegistry present)."));
+			assertThat(e.getMessage()).contains("failed to look up MessageChannel with name 'foo' in the BeanFactory" +
+					" " +
+					"(and there is no HeaderChannelRegistry present).");
 		}
 	}
 
@@ -267,12 +258,12 @@ public class HeaderChannelRegistryTests {
 		MessageChannel channel = new DirectChannel();
 		String foo = (String) registry.channelToChannelName(channel);
 		Map<?, ?> map = TestUtils.getPropertyValue(registry, "channels", Map.class);
-		assertEquals(1, map.size());
-		assertSame(channel, registry.channelNameToChannel(foo));
-		assertEquals(1, map.size());
+		assertThat(map.size()).isEqualTo(1);
+		assertThat(registry.channelNameToChannel(foo)).isSameAs(channel);
+		assertThat(map.size()).isEqualTo(1);
 		registry.setRemoveOnGet(true);
-		assertSame(channel, registry.channelNameToChannel(foo));
-		assertEquals(0, map.size());
+		assertThat(registry.channelNameToChannel(foo)).isSameAs(channel);
+		assertThat(map.size()).isEqualTo(0);
 	}
 
 
@@ -280,10 +271,14 @@ public class HeaderChannelRegistryTests {
 
 		@Override
 		protected Object handleRequestMessage(Message<?> requestMessage) {
-			assertThat(requestMessage.getHeaders().getReplyChannel(),
-					Matchers.anyOf(instanceOf(String.class), Matchers.nullValue()));
-			assertThat(requestMessage.getHeaders().getErrorChannel(),
-					Matchers.anyOf(instanceOf(String.class), Matchers.nullValue()));
+			assertThat(requestMessage.getHeaders().getReplyChannel())
+					.satisfiesAnyOf(
+							replyChannel -> assertThat(replyChannel).isInstanceOf(String.class),
+							replyChannel -> assertThat(replyChannel).isNull());
+			assertThat(requestMessage.getHeaders().getErrorChannel())
+					.satisfiesAnyOf(
+							errorChannel -> assertThat(errorChannel).isInstanceOf(String.class),
+							errorChannel -> assertThat(errorChannel).isNull());
 			if (requestMessage.getPayload().equals("bar")) {
 				throw new RuntimeException("intentional");
 			}

spring-integration-core/src/test/java/org/springframework/integration/codec/kryo/CompositeCodecTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2015-2016 the original author or authors.
+ * Copyright 2015-2019 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -16,7 +16,7 @@
 
 package org.springframework.integration.codec.kryo;
 
-import static org.junit.Assert.assertEquals;
+import static org.assertj.core.api.Assertions.assertThat;
 
 import java.io.IOException;
 import java.util.HashMap;
@@ -49,7 +49,7 @@ public class CompositeCodecTests {
 		SomeClassWithNoDefaultConstructors foo2 = this.codec.decode(
 				this.codec.encode(foo),
 				SomeClassWithNoDefaultConstructors.class);
-		assertEquals(foo, foo2);
+		assertThat(foo2).isEqualTo(foo);
 	}
 
 	static class SomeClassWithNoDefaultConstructors {

spring-integration-core/src/test/java/org/springframework/integration/codec/kryo/FileKryoRegistrarTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2015-2016 the original author or authors.
+ * Copyright 2015-2019 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -16,7 +16,7 @@
 
 package org.springframework.integration.codec.kryo;
 
-import static org.junit.Assert.assertEquals;
+import static org.assertj.core.api.Assertions.assertThat;
 
 import java.io.File;
 import java.io.IOException;
@@ -35,7 +35,7 @@ public class FileKryoRegistrarTests {
 		PojoCodec pc = new PojoCodec(new FileKryoRegistrar());
 		File file = new File("/foo/bar");
 		File file2 = pc.decode(pc.encode(file), File.class);
-		assertEquals(file, file2);
+		assertThat(file2).isEqualTo(file);
 	}
 
 }

spring-integration-core/src/test/java/org/springframework/integration/codec/kryo/KryoCodecTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2015-2016 the original author or authors.
+ * Copyright 2015-2019 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -16,7 +16,7 @@
 
 package org.springframework.integration.codec.kryo;
 
-import static org.junit.Assert.assertEquals;
+import static org.assertj.core.api.Assertions.assertThat;
 
 import java.io.ByteArrayOutputStream;
 import java.io.File;
@@ -26,10 +26,13 @@ import java.io.IOException;
 import java.util.HashMap;
 import java.util.Map;
 
+import org.assertj.core.data.Offset;
 import org.junit.Test;
 
 /**
  * @author David Turanski
+ * @author Artem Bilan
+ *
  * @since 4.2
  */
 public class KryoCodecTests {
@@ -43,7 +46,7 @@ public class KryoCodecTests {
 		codec.encode(str, bos);
 
 		String s2 = codec.decode(bos.toByteArray(), String.class);
-		assertEquals(str, s2);
+		assertThat(s2).isEqualTo(str);
 	}
 
 	@Test
@@ -58,7 +61,7 @@ public class KryoCodecTests {
 		FileInputStream fis = new FileInputStream(file);
 		String s2 = codec.decode(fis, String.class);
 		file.delete();
-		assertEquals(str, s2);
+		assertThat(s2).isEqualTo(str);
 	}
 
 	@Test
@@ -68,7 +71,7 @@ public class KryoCodecTests {
 		ByteArrayOutputStream bos = new ByteArrayOutputStream();
 		codec.encode(foo, bos);
 		Object foo2 = codec.decode(bos.toByteArray(), SomeClassWithNoDefaultConstructors.class);
-		assertEquals(foo, foo2);
+		assertThat(foo2).isEqualTo(foo);
 	}
 
 	@Test
@@ -78,36 +81,36 @@ public class KryoCodecTests {
 		ByteArrayOutputStream bos = new ByteArrayOutputStream();
 		codec.encode(true, bos);
 		boolean b = codec.decode(bos.toByteArray(), Boolean.class);
-		assertEquals(true, b);
+		assertThat(b).isEqualTo(true);
 		b = codec.decode(bos.toByteArray(), boolean.class);
-		assertEquals(true, b);
+		assertThat(b).isEqualTo(true);
 
 		bos = new ByteArrayOutputStream();
 		codec.encode(3.14159, bos);
 
 		double d = codec.decode(bos.toByteArray(), double.class);
-		assertEquals(3.14159, d, 0.00001);
+		assertThat(d).isCloseTo(3.14159, Offset.offset(0.00001));
 
 		bos = new ByteArrayOutputStream();
 		codec.encode(3.14159, bos);
 
 		d = codec.decode(bos.toByteArray(), Double.class);
-		assertEquals(3.14159, d, 0.00001);
+		assertThat(d).isCloseTo(3.14159, Offset.offset(0.00001));
 
 	}
 
 	@Test
 	public void testMapSerialization() throws IOException {
 		PojoCodec codec = new PojoCodec();
-		Map<String, Integer> map = new HashMap<String, Integer>();
+		Map<String, Integer> map = new HashMap<>();
 		map.put("one", 1);
 		map.put("two", 2);
 		ByteArrayOutputStream bos = new ByteArrayOutputStream();
 		codec.encode(map, bos);
 		Map<?, ?> m2 = (Map<?, ?>) codec.decode(bos.toByteArray(), HashMap.class);
-		assertEquals(2, m2.size());
-		assertEquals(1, m2.get("one"));
-		assertEquals(2, m2.get("two"));
+		assertThat(m2.size()).isEqualTo(2);
+		assertThat(m2.get("one")).isEqualTo(1);
+		assertThat(m2.get("two")).isEqualTo(2);
 	}
 
 	@Test
@@ -120,8 +123,8 @@ public class KryoCodecTests {
 		codec.encode(foo, bos);
 
 		Foo foo2 = codec.decode(bos.toByteArray(), Foo.class);
-		assertEquals(1, foo2.get("one"));
-		assertEquals(2, foo2.get("two"));
+		assertThat(foo2.get("one")).isEqualTo(1);
+		assertThat(foo2.get("two")).isEqualTo(2);
 	}
 
 	static class SomeClassWithNoDefaultConstructors {
@@ -158,7 +161,7 @@ public class KryoCodecTests {
 		private Map<Object, Object> map;
 
 		Foo() {
-			map = new HashMap<Object, Object>();
+			this.map = new HashMap<>();
 		}
 
 		public void put(Object key, Object value) {

spring-integration-core/src/test/java/org/springframework/integration/config/AggregatorParserTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2018 the original author or authors.
+ * Copyright 2002-2019 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -16,24 +16,14 @@
 
 package org.springframework.integration.config;
 
-import static org.hamcrest.CoreMatchers.instanceOf;
-import static org.hamcrest.CoreMatchers.is;
-import static org.hamcrest.Matchers.containsString;
-import static org.junit.Assert.assertEquals;
-import static org.junit.Assert.assertFalse;
-import static org.junit.Assert.assertNotNull;
-import static org.junit.Assert.assertNull;
-import static org.junit.Assert.assertSame;
-import static org.junit.Assert.assertThat;
-import static org.junit.Assert.assertTrue;
-import static org.junit.Assert.fail;
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.assertj.core.api.Assertions.fail;
 
 import java.util.ArrayList;
 import java.util.Collection;
 import java.util.List;
 import java.util.concurrent.atomic.AtomicReference;
 
-import org.junit.Assert;
 import org.junit.Test;
 import org.junit.runner.RunWith;
 
@@ -92,14 +82,15 @@ public class AggregatorParserTests {
 
 		outboundMessages.forEach(input::send);
 
-		assertEquals("One and only one message must have been aggregated", 1,
-				aggregatorBean.getAggregatedMessages().size());
+		assertThat(aggregatorBean.getAggregatedMessages().size())
+				.as("One and only one message must have been aggregated").isEqualTo(1);
 		Message<?> aggregatedMessage = aggregatorBean.getAggregatedMessages().get("id1");
-		assertEquals("The aggregated message payload is not correct", "123456789", aggregatedMessage.getPayload());
+		assertThat(aggregatedMessage.getPayload()).as("The aggregated message payload is not correct")
+				.isEqualTo("123456789");
 		Object mbf = context.getBean(IntegrationUtils.INTEGRATION_MESSAGE_BUILDER_FACTORY_BEAN_NAME);
 		Object handler = context.getBean("aggregatorWithReference.handler");
-		assertSame(mbf, TestUtils.getPropertyValue(handler, "outputProcessor.messageBuilderFactory"));
-		assertTrue(TestUtils.getPropertyValue(handler, "releaseLockBeforeSend", Boolean.class));
+		assertThat(TestUtils.getPropertyValue(handler, "outputProcessor.messageBuilderFactory")).isSameAs(mbf);
+		assertThat(TestUtils.getPropertyValue(handler, "releaseLockBeforeSend", Boolean.class)).isTrue();
 	}
 
 	@Test
@@ -114,10 +105,10 @@ public class AggregatorParserTests {
 
 		outboundMessages.forEach(input::send);
 
-		assertEquals(3, output.getQueueSize());
+		assertThat(output.getQueueSize()).isEqualTo(3);
 		output.purge(null);
-		assertFalse(TestUtils.getPropertyValue(context.getBean("aggregatorWithMGPReference.handler"),
-				"releaseLockBeforeSend", Boolean.class));
+		assertThat(TestUtils.getPropertyValue(context.getBean("aggregatorWithMGPReference.handler"),
+				"releaseLockBeforeSend", Boolean.class)).isFalse();
 	}
 
 	@Test
@@ -132,7 +123,7 @@ public class AggregatorParserTests {
 
 		outboundMessages.forEach(input::send);
 
-		assertEquals(3, output.getQueueSize());
+		assertThat(output.getQueueSize()).isEqualTo(3);
 		output.purge(null);
 	}
 
@@ -149,12 +140,12 @@ public class AggregatorParserTests {
 
 		outboundMessages.forEach(input::send);
 
-		assertEquals("The aggregated message payload is not correct", "[123]", aggregatedMessage.get().getPayload()
-				.toString());
+		assertThat(aggregatedMessage.get().getPayload()
+				.toString()).as("The aggregated message payload is not correct").isEqualTo("[123]");
 		Object mbf = context.getBean(IntegrationUtils.INTEGRATION_MESSAGE_BUILDER_FACTORY_BEAN_NAME);
 		Object handler = context.getBean("aggregatorWithExpressions.handler");
-		assertSame(mbf, TestUtils.getPropertyValue(handler, "outputProcessor.messageBuilderFactory"));
-		assertTrue(TestUtils.getPropertyValue(handler, "expireGroupsUponTimeout", Boolean.class));
+		assertThat(TestUtils.getPropertyValue(handler, "outputProcessor.messageBuilderFactory")).isSameAs(mbf);
+		assertThat(TestUtils.getPropertyValue(handler, "expireGroupsUponTimeout", Boolean.class)).isTrue();
 	}
 
 	@Test
@@ -165,40 +156,46 @@ public class AggregatorParserTests {
 		MessageChannel outputChannel = (MessageChannel) context.getBean("outputChannel");
 		MessageChannel discardChannel = (MessageChannel) context.getBean("discardChannel");
 		Object consumer = new DirectFieldAccessor(endpoint).getPropertyValue("handler");
-		assertThat(consumer, is(instanceOf(AggregatingMessageHandler.class)));
+		assertThat(consumer).isInstanceOf(AggregatingMessageHandler.class);
 		DirectFieldAccessor accessor = new DirectFieldAccessor(consumer);
 		Object handlerMethods = new DirectFieldAccessor(new DirectFieldAccessor(new DirectFieldAccessor(accessor
 				.getPropertyValue("outputProcessor")).getPropertyValue("processor")).getPropertyValue("delegate"))
 				.getPropertyValue("handlerMethods");
-		assertNull(handlerMethods);
+		assertThat(handlerMethods).isNull();
 		Object handlerMethod = new DirectFieldAccessor(new DirectFieldAccessor(new DirectFieldAccessor(accessor
 				.getPropertyValue("outputProcessor")).getPropertyValue("processor")).getPropertyValue("delegate"))
 				.getPropertyValue("handlerMethod");
-		assertTrue(handlerMethod.toString().contains("createSingleMessageFromGroup"));
-		assertEquals("The AggregatorEndpoint is not injected with the appropriate ReleaseStrategy instance",
-				releaseStrategy, accessor.getPropertyValue("releaseStrategy"));
-		assertEquals("The AggregatorEndpoint is not injected with the appropriate CorrelationStrategy instance",
-				correlationStrategy, accessor.getPropertyValue("correlationStrategy"));
-		assertEquals("The AggregatorEndpoint is not injected with the appropriate output channel",
-				outputChannel, accessor.getPropertyValue("outputChannel"));
-		assertEquals("The AggregatorEndpoint is not injected with the appropriate discard channel",
-				discardChannel, accessor.getPropertyValue("discardChannel"));
-		assertEquals("The AggregatorEndpoint is not set with the appropriate timeout value", 86420000L,
-				TestUtils.getPropertyValue(consumer, "messagingTemplate.sendTimeout"));
-		assertEquals(
-				"The AggregatorEndpoint is not configured with the appropriate 'send partial results on timeout' flag",
-				true, accessor.getPropertyValue("sendPartialResultOnExpiry"));
-		assertFalse(TestUtils.getPropertyValue(consumer, "expireGroupsUponTimeout", Boolean.class));
-		assertTrue(TestUtils.getPropertyValue(consumer, "expireGroupsUponCompletion", Boolean.class));
-		assertEquals(123L, TestUtils.getPropertyValue(consumer, "minimumTimeoutForEmptyGroups"));
-		assertEquals("456", TestUtils.getPropertyValue(consumer, "groupTimeoutExpression", Expression.class)
-				.getExpressionString());
-		assertSame(this.context.getBean(LockRegistry.class), TestUtils.getPropertyValue(consumer, "lockRegistry"));
-		assertSame(this.context.getBean("scheduler"), TestUtils.getPropertyValue(consumer, "taskScheduler"));
-		assertSame(this.context.getBean("store"), TestUtils.getPropertyValue(consumer, "messageStore"));
-		assertEquals(5, TestUtils.getPropertyValue(consumer, "order"));
-		assertNotNull(TestUtils.getPropertyValue(consumer, "forceReleaseAdviceChain"));
-		assertFalse(TestUtils.getPropertyValue(consumer, "popSequence", Boolean.class));
+		assertThat(handlerMethod.toString().contains("createSingleMessageFromGroup")).isTrue();
+		assertThat(accessor.getPropertyValue("releaseStrategy"))
+				.as("The AggregatorEndpoint is not injected with the appropriate ReleaseStrategy instance")
+				.isEqualTo(releaseStrategy);
+		assertThat(accessor.getPropertyValue("correlationStrategy"))
+				.as("The AggregatorEndpoint is not injected with the appropriate CorrelationStrategy instance")
+				.isEqualTo(correlationStrategy);
+		assertThat(accessor.getPropertyValue("outputChannel"))
+				.as("The AggregatorEndpoint is not injected with the appropriate output channel")
+				.isEqualTo(outputChannel);
+		assertThat(accessor.getPropertyValue("discardChannel"))
+				.as("The AggregatorEndpoint is not injected with the appropriate discard channel")
+				.isEqualTo(discardChannel);
+		assertThat(TestUtils.getPropertyValue(consumer, "messagingTemplate.sendTimeout"))
+				.as("The AggregatorEndpoint is not set with the appropriate timeout value").isEqualTo(86420000L);
+		assertThat(accessor.getPropertyValue("sendPartialResultOnExpiry"))
+				.as("The AggregatorEndpoint is not configured with the appropriate 'send partial results on timeout' " +
+						"flag")
+				.isEqualTo(true);
+		assertThat(TestUtils.getPropertyValue(consumer, "expireGroupsUponTimeout", Boolean.class)).isFalse();
+		assertThat(TestUtils.getPropertyValue(consumer, "expireGroupsUponCompletion", Boolean.class)).isTrue();
+		assertThat(TestUtils.getPropertyValue(consumer, "minimumTimeoutForEmptyGroups")).isEqualTo(123L);
+		assertThat(TestUtils.getPropertyValue(consumer, "groupTimeoutExpression", Expression.class)
+				.getExpressionString()).isEqualTo("456");
+		assertThat(TestUtils.getPropertyValue(consumer, "lockRegistry"))
+				.isSameAs(this.context.getBean(LockRegistry.class));
+		assertThat(TestUtils.getPropertyValue(consumer, "taskScheduler")).isSameAs(this.context.getBean("scheduler"));
+		assertThat(TestUtils.getPropertyValue(consumer, "messageStore")).isSameAs(this.context.getBean("store"));
+		assertThat(TestUtils.getPropertyValue(consumer, "order")).isEqualTo(5);
+		assertThat(TestUtils.getPropertyValue(consumer, "forceReleaseAdviceChain")).isNotNull();
+		assertThat(TestUtils.getPropertyValue(consumer, "popSequence", Boolean.class)).isFalse();
 	}
 
 	@Test
@@ -211,10 +208,10 @@ public class AggregatorParserTests {
 		outboundMessages.forEach(input::send);
 		PollableChannel outputChannel = (PollableChannel) context.getBean("outputChannel");
 		Message<?> response = outputChannel.receive(10);
-		Assert.assertEquals(6L, response.getPayload());
+		assertThat(response.getPayload()).isEqualTo(6L);
 		Object mbf = context.getBean(IntegrationUtils.INTEGRATION_MESSAGE_BUILDER_FACTORY_BEAN_NAME);
 		Object handler = context.getBean("aggregatorWithReferenceAndMethod.handler");
-		assertSame(mbf, TestUtils.getPropertyValue(handler, "outputProcessor.messageBuilderFactory"));
+		assertThat(TestUtils.getPropertyValue(handler, "outputProcessor.messageBuilderFactory")).isSameAs(mbf);
 	}
 
 	@Test
@@ -224,7 +221,7 @@ public class AggregatorParserTests {
 			fail("Expected exception");
 		}
 		catch (BeanCreationException e) {
-			assertThat(e.getMessage(), containsString("Adder] has no eligible methods"));
+			assertThat(e.getMessage()).contains("Adder] has no eligible methods");
 		}
 	}
 
@@ -235,7 +232,7 @@ public class AggregatorParserTests {
 			fail("Expected exception");
 		}
 		catch (BeanCreationException e) {
-			assertThat(e.getMessage(), containsString("No bean named 'testReleaseStrategy' available"));
+			assertThat(e.getMessage()).contains("No bean named 'testReleaseStrategy' available");
 		}
 	}
 
@@ -246,23 +243,23 @@ public class AggregatorParserTests {
 		EventDrivenConsumer endpoint = this.context.getBean("aggregatorWithPojoReleaseStrategy", EventDrivenConsumer.class);
 		ReleaseStrategy releaseStrategy =
 				TestUtils.getPropertyValue(endpoint, "handler.releaseStrategy", ReleaseStrategy.class);
-		Assert.assertTrue(releaseStrategy instanceof MethodInvokingReleaseStrategy);
+		assertThat(releaseStrategy instanceof MethodInvokingReleaseStrategy).isTrue();
 		MessagingMethodInvokerHelper<Long> methodInvokerHelper =
 				TestUtils.getPropertyValue(releaseStrategy, "adapter.delegate", MessagingMethodInvokerHelper.class);
 		Object handlerMethods = TestUtils.getPropertyValue(methodInvokerHelper, "handlerMethods");
-		assertNull(handlerMethods);
+		assertThat(handlerMethods).isNull();
 		Object handlerMethod = TestUtils.getPropertyValue(methodInvokerHelper, "handlerMethod");
-		assertTrue(handlerMethod.toString().contains("checkCompleteness"));
+		assertThat(handlerMethod.toString().contains("checkCompleteness")).isTrue();
 		input.send(createMessage(1L, "correlationId", 4, 0, null));
 		input.send(createMessage(2L, "correlationId", 4, 1, null));
 		input.send(createMessage(3L, "correlationId", 4, 2, null));
 		PollableChannel outputChannel = (PollableChannel) context.getBean("outputChannel");
 		Message<?> reply = outputChannel.receive(0);
-		Assert.assertNull(reply);
+		assertThat(reply).isNull();
 		input.send(createMessage(5L, "correlationId", 4, 3, null));
 		reply = outputChannel.receive(0);
-		Assert.assertNotNull(reply);
-		assertEquals(11L, reply.getPayload());
+		assertThat(reply).isNotNull();
+		assertThat(reply.getPayload()).isEqualTo(11L);
 	}
 
 	@Test // see INT-2011
@@ -271,23 +268,23 @@ public class AggregatorParserTests {
 		EventDrivenConsumer endpoint = (EventDrivenConsumer) context.getBean("aggregatorWithPojoReleaseStrategyAsCollection");
 		ReleaseStrategy releaseStrategy = (ReleaseStrategy) new DirectFieldAccessor(new DirectFieldAccessor(endpoint)
 				.getPropertyValue("handler")).getPropertyValue("releaseStrategy");
-		Assert.assertTrue(releaseStrategy instanceof MethodInvokingReleaseStrategy);
+		assertThat(releaseStrategy instanceof MethodInvokingReleaseStrategy).isTrue();
 		DirectFieldAccessor releaseStrategyAccessor = new DirectFieldAccessor(new DirectFieldAccessor(new DirectFieldAccessor(releaseStrategy)
 				.getPropertyValue("adapter")).getPropertyValue("delegate"));
 		Object handlerMethods = releaseStrategyAccessor.getPropertyValue("handlerMethods");
-		assertNull(handlerMethods);
+		assertThat(handlerMethods).isNull();
 		Object handlerMethod = releaseStrategyAccessor.getPropertyValue("handlerMethod");
-		assertTrue(handlerMethod.toString().contains("checkCompleteness"));
+		assertThat(handlerMethod.toString().contains("checkCompleteness")).isTrue();
 		input.send(createMessage(1L, "correlationId", 4, 0, null));
 		input.send(createMessage(2L, "correlationId", 4, 1, null));
 		input.send(createMessage(3L, "correlationId", 4, 2, null));
 		PollableChannel outputChannel = (PollableChannel) context.getBean("outputChannel");
 		Message<?> reply = outputChannel.receive(0);
-		Assert.assertNull(reply);
+		assertThat(reply).isNull();
 		input.send(createMessage(5L, "correlationId", 4, 3, null));
 		reply = outputChannel.receive(0);
-		Assert.assertNotNull(reply);
-		assertEquals(11L, reply.getPayload());
+		assertThat(reply).isNotNull();
+		assertThat(reply.getPayload()).isEqualTo(11L);
 	}
 
 	@Test
@@ -297,7 +294,7 @@ public class AggregatorParserTests {
 			fail("Expected exception");
 		}
 		catch (BeanCreationException e) {
-			assertThat(e.getMessage(), containsString("TestReleaseStrategy] has no eligible methods"));
+			assertThat(e.getMessage()).contains("TestReleaseStrategy] has no eligible methods");
 		}
 	}
 
@@ -306,15 +303,17 @@ public class AggregatorParserTests {
 		EventDrivenConsumer aggregatorConsumer = (EventDrivenConsumer) context.getBean("aggregatorWithExpressionsAndPojoAggregator");
 		AggregatingMessageHandler aggregatingMessageHandler = (AggregatingMessageHandler) TestUtils.getPropertyValue(aggregatorConsumer, "handler");
 		MethodInvokingMessageGroupProcessor messageGroupProcessor = (MethodInvokingMessageGroupProcessor) TestUtils.getPropertyValue(aggregatingMessageHandler, "outputProcessor");
-		Object messageGroupProcessorTargetObject = TestUtils.getPropertyValue(messageGroupProcessor, "processor.delegate.targetObject");
-		assertSame(context.getBean("aggregatorBean"), messageGroupProcessorTargetObject);
+		Object messageGroupProcessorTargetObject = TestUtils.getPropertyValue(messageGroupProcessor, "processor" +
+				".delegate.targetObject");
+		assertThat(messageGroupProcessorTargetObject).isSameAs(context.getBean("aggregatorBean"));
 		ReleaseStrategy releaseStrategy = (ReleaseStrategy) TestUtils.getPropertyValue(aggregatingMessageHandler, "releaseStrategy");
 		CorrelationStrategy correlationStrategy = (CorrelationStrategy) TestUtils.getPropertyValue(aggregatingMessageHandler, "correlationStrategy");
-		Long minimumTimeoutForEmptyGroups = TestUtils.getPropertyValue(aggregatingMessageHandler, "minimumTimeoutForEmptyGroups", Long.class);
+		Long minimumTimeoutForEmptyGroups = TestUtils.getPropertyValue(aggregatingMessageHandler,
+				"minimumTimeoutForEmptyGroups", Long.class);
 
-		assertTrue(ExpressionEvaluatingReleaseStrategy.class.equals(releaseStrategy.getClass()));
-		assertTrue(ExpressionEvaluatingCorrelationStrategy.class.equals(correlationStrategy.getClass()));
-		assertEquals(60000L, minimumTimeoutForEmptyGroups.longValue());
+		assertThat(ExpressionEvaluatingReleaseStrategy.class.equals(releaseStrategy.getClass())).isTrue();
+		assertThat(ExpressionEvaluatingCorrelationStrategy.class.equals(correlationStrategy.getClass())).isTrue();
+		assertThat(minimumTimeoutForEmptyGroups.longValue()).isEqualTo(60000L);
 	}
 
 	@Test
@@ -323,8 +322,8 @@ public class AggregatorParserTests {
 			new ClassPathXmlApplicationContext("aggregatorParserFailTests.xml", this.getClass()).close();
 		}
 		catch (BeanDefinitionParsingException e) {
-			assertThat(e.getMessage(), containsString(
-					"Exactly one of the 'release-strategy' or 'release-strategy-expression' attribute is allowed."));
+			assertThat(e.getMessage())
+					.contains("Exactly one of the 'release-strategy' or 'release-strategy-expression' attribute is allowed.");
 		}
 	}
 

spring-integration-core/src/test/java/org/springframework/integration/config/AggregatorWithCorrelationStrategyTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2018 the original author or authors.
+ * Copyright 2002-2019 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -16,12 +16,10 @@
 
 package org.springframework.integration.config;
 
-import static org.hamcrest.CoreMatchers.containsString;
-import static org.junit.Assert.assertThat;
+import static org.assertj.core.api.Assertions.assertThat;
 
 import java.util.List;
 
-import org.junit.Assert;
 import org.junit.Test;
 import org.junit.runner.RunWith;
 
@@ -97,9 +95,9 @@ public class AggregatorWithCorrelationStrategyTests {
 
 	private void receiveAndCompare(PollableChannel outputChannel, String... expectedValues) {
 		Message<?> message = outputChannel.receive(500);
-		Assert.assertNotNull(message);
+		assertThat(message).isNotNull();
 		for (String expectedValue : expectedValues) {
-			assertThat((String) message.getPayload(), containsString(expectedValue));
+			assertThat((String) message.getPayload()).contains(expectedValue);
 		}
 	}
 

spring-integration-core/src/test/java/org/springframework/integration/config/AggregatorWithMessageStoreParserTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2016 the original author or authors.
+ * Copyright 2002-2019 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -16,7 +16,7 @@
 
 package org.springframework.integration.config;
 
-import static org.junit.Assert.assertEquals;
+import static org.assertj.core.api.Assertions.assertThat;
 
 import org.junit.Test;
 import org.junit.runner.RunWith;
@@ -58,15 +58,16 @@ public class AggregatorWithMessageStoreParserTests {
 	@DirtiesContext
 	public void testAggregation() {
 		input.send(createMessage("123", "id1", 3, 1, null));
-		assertEquals(1, messageGroupStore.getMessageGroup("id1").size());
+		assertThat(messageGroupStore.getMessageGroup("id1").size()).isEqualTo(1);
 		input.send(createMessage("789", "id1", 3, 3, null));
-		assertEquals(2, messageGroupStore.getMessageGroup("id1").size());
+		assertThat(messageGroupStore.getMessageGroup("id1").size()).isEqualTo(2);
 		input.send(createMessage("456", "id1", 3, 2, null));
-		assertEquals("One and only one message should have been aggregated", 1, aggregatorBean
-				.getAggregatedMessages().size());
+		assertThat(aggregatorBean
+				.getAggregatedMessages().size()).as("One and only one message should have been aggregated")
+				.isEqualTo(1);
 		Message<?> aggregatedMessage = aggregatorBean.getAggregatedMessages().get("id1");
-		assertEquals("The aggregated message payload is not correct", "123456789", aggregatedMessage
-				.getPayload());
+		assertThat(aggregatedMessage
+				.getPayload()).as("The aggregated message payload is not correct").isEqualTo("123456789");
 	}
 
 
@@ -74,15 +75,16 @@ public class AggregatorWithMessageStoreParserTests {
 	@DirtiesContext
 	public void testExpiry() {
 		input.send(createMessage("123", "id1", 3, 1, null));
-		assertEquals(1, messageGroupStore.getMessageGroup("id1").size());
+		assertThat(messageGroupStore.getMessageGroup("id1").size()).isEqualTo(1);
 		input.send(createMessage("456", "id1", 3, 2, null));
-		assertEquals(2, messageGroupStore.getMessageGroup("id1").size());
+		assertThat(messageGroupStore.getMessageGroup("id1").size()).isEqualTo(2);
 		this.controlBusChannel.send(new GenericMessage<Object>("@messageStore.expireMessageGroups(-10000)"));
-		assertEquals("One and only one message should have been aggregated", 1, aggregatorBean
-				.getAggregatedMessages().size());
+		assertThat(aggregatorBean
+				.getAggregatedMessages().size()).as("One and only one message should have been aggregated")
+				.isEqualTo(1);
 		Message<?> aggregatedMessage = aggregatorBean.getAggregatedMessages().get("id1");
-		assertEquals("The aggregated message payload is not correct", "123456", aggregatedMessage
-				.getPayload());
+		assertThat(aggregatedMessage
+				.getPayload()).as("The aggregated message payload is not correct").isEqualTo("123456");
 	}
 
 

spring-integration-core/src/test/java/org/springframework/integration/config/ChainParserTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2017 the original author or authors.
+ * Copyright 2002-2019 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -16,15 +16,8 @@
 
 package org.springframework.integration.config;
 
-import static org.hamcrest.Matchers.instanceOf;
-import static org.junit.Assert.assertEquals;
-import static org.junit.Assert.assertFalse;
-import static org.junit.Assert.assertNotNull;
-import static org.junit.Assert.assertNull;
-import static org.junit.Assert.assertSame;
-import static org.junit.Assert.assertThat;
-import static org.junit.Assert.assertTrue;
-import static org.junit.Assert.fail;
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.assertj.core.api.Assertions.fail;
 import static org.mockito.ArgumentMatchers.any;
 import static org.mockito.Mockito.doAnswer;
 import static org.mockito.Mockito.mock;
@@ -34,8 +27,6 @@ import java.util.List;
 import java.util.concurrent.atomic.AtomicReference;
 
 import org.apache.commons.logging.Log;
-import org.hamcrest.Factory;
-import org.hamcrest.Matcher;
 import org.junit.Test;
 import org.junit.runner.RunWith;
 
@@ -58,9 +49,9 @@ import org.springframework.integration.handler.LoggingHandler;
 import org.springframework.integration.handler.MessageHandlerChain;
 import org.springframework.integration.handler.ReplyRequiredException;
 import org.springframework.integration.handler.ServiceActivatingHandler;
-import org.springframework.integration.message.MessageMatcher;
 import org.springframework.integration.support.MessageBuilder;
 import org.springframework.integration.support.json.JsonObjectMapper;
+import org.springframework.integration.test.predicate.MessagePredicate;
 import org.springframework.integration.test.util.TestUtils;
 import org.springframework.integration.transformer.MessageTransformingHandler;
 import org.springframework.integration.transformer.ObjectToMapTransformer;
@@ -174,18 +165,13 @@ public class ChainParserTests {
 
 	public static Message<?> successMessage = MessageBuilder.withPayload("success").build();
 
-	@Factory
-	public static Matcher<Message<?>> sameExceptImmutableHeaders(Message<?> expected) {
-		return new MessageMatcher(expected);
-	}
-
 	@Test
 	public void chainWithAcceptingFilter() {
 		Message<?> message = MessageBuilder.withPayload("test").build();
 		this.filterInput.send(message);
 		Message<?> reply = this.output.receive(1000);
-		assertNotNull(reply);
-		assertEquals("foo", reply.getPayload());
+		assertThat(reply).isNotNull();
+		assertThat(reply.getPayload()).isEqualTo("foo");
 	}
 
 	@Test
@@ -193,7 +179,7 @@ public class ChainParserTests {
 		Message<?> message = MessageBuilder.withPayload(123).build();
 		this.filterInput.send(message);
 		Message<?> reply = this.output.receive(0);
-		assertNull(reply);
+		assertThat(reply).isNull();
 	}
 
 	@Test
@@ -201,11 +187,11 @@ public class ChainParserTests {
 		Message<?> message = MessageBuilder.withPayload(123).build();
 		this.headerEnricherInput.send(message);
 		Message<?> reply = this.replyOutput.receive(1000);
-		assertNotNull(reply);
-		assertEquals("foo", reply.getPayload());
-		assertEquals("ABC", new IntegrationMessageHeaderAccessor(reply).getCorrelationId());
-		assertEquals("XYZ", reply.getHeaders().get("testValue"));
-		assertEquals(123, reply.getHeaders().get("testRef"));
+		assertThat(reply).isNotNull();
+		assertThat(reply.getPayload()).isEqualTo("foo");
+		assertThat(new IntegrationMessageHeaderAccessor(reply).getCorrelationId()).isEqualTo("ABC");
+		assertThat(reply.getHeaders().get("testValue")).isEqualTo("XYZ");
+		assertThat(reply.getHeaders().get("testRef")).isEqualTo(123);
 	}
 
 	@Test
@@ -213,8 +199,8 @@ public class ChainParserTests {
 		Message<?> message = MessageBuilder.withPayload("test").build();
 		this.pollableInput1.send(message);
 		Message<?> reply = this.output.receive(3000);
-		assertNotNull(reply);
-		assertEquals("foo", reply.getPayload());
+		assertThat(reply).isNotNull();
+		assertThat(reply.getPayload()).isEqualTo("foo");
 	}
 
 	@Test
@@ -222,76 +208,76 @@ public class ChainParserTests {
 		Message<?> message = MessageBuilder.withPayload("test").build();
 		this.pollableInput2.send(message);
 		Message<?> reply = this.output.receive(3000);
-		assertNotNull(reply);
-		assertEquals("foo", reply.getPayload());
+		assertThat(reply).isNotNull();
+		assertThat(reply.getPayload()).isEqualTo("foo");
 	}
 
 	@Test
-	public void chainHandlerBean() throws Exception {
+	public void chainHandlerBean() {
 		Message<?> message = MessageBuilder.withPayload("test").build();
 		this.beanInput.send(message);
 		Message<?> reply = this.output.receive(3000);
-		assertNotNull(reply);
-		assertThat(reply, sameExceptImmutableHeaders(successMessage));
+		assertThat(reply).isNotNull();
+		assertThat(reply).matches(new MessagePredicate(successMessage));
 	}
 
 	@SuppressWarnings("rawtypes")
 	@Test
-	public void chainNestingAndAggregation() throws Exception {
+	public void chainNestingAndAggregation() {
 		Message<?> message = MessageBuilder.withPayload("test").setCorrelationId(1).setSequenceSize(1).build();
 		this.aggregatorInput.send(message);
 		Message reply = this.output.receive(3000);
-		assertNotNull(reply);
-		assertEquals("foo", reply.getPayload());
+		assertThat(reply).isNotNull();
+		assertThat(reply.getPayload()).isEqualTo("foo");
 	}
 
 	@Test
-	public void chainWithPayloadTypeRouter() throws Exception {
+	public void chainWithPayloadTypeRouter() {
 		Message<?> message1 = MessageBuilder.withPayload("test").build();
 		Message<?> message2 = MessageBuilder.withPayload(123).build();
 		this.payloadTypeRouterInput.send(message1);
 		this.payloadTypeRouterInput.send(message2);
 		Message<?> reply1 = this.strings.receive(1000);
 		Message<?> reply2 = this.numbers.receive(1000);
-		assertNotNull(reply1);
-		assertNotNull(reply2);
-		assertEquals("test", reply1.getPayload());
-		assertEquals(123, reply2.getPayload());
+		assertThat(reply1).isNotNull();
+		assertThat(reply2).isNotNull();
+		assertThat(reply1.getPayload()).isEqualTo("test");
+		assertThat(reply2.getPayload()).isEqualTo(123);
 	}
 
 	@Test // INT-2315
-	public void chainWithHeaderValueRouter() throws Exception {
+	public void chainWithHeaderValueRouter() {
 		Message<?> message1 = MessageBuilder.withPayload("test").setHeader("routingHeader", "strings").build();
 		Message<?> message2 = MessageBuilder.withPayload(123).setHeader("routingHeader", "numbers").build();
 		this.headerValueRouterInput.send(message1);
 		this.headerValueRouterInput.send(message2);
 		Message<?> reply1 = this.strings.receive(1000);
 		Message<?> reply2 = this.numbers.receive(1000);
-		assertNotNull(reply1);
-		assertNotNull(reply2);
-		assertEquals("test", reply1.getPayload());
-		assertEquals(123, reply2.getPayload());
+		assertThat(reply1).isNotNull();
+		assertThat(reply2).isNotNull();
+		assertThat(reply1.getPayload()).isEqualTo("test");
+		assertThat(reply2.getPayload()).isEqualTo(123);
 	}
 
 	@Test // INT-2315
-	public void chainWithHeaderValueRouterWithMapping() throws Exception {
+	public void chainWithHeaderValueRouterWithMapping() {
 		Message<?> message1 = MessageBuilder.withPayload("test").setHeader("routingHeader", "isString").build();
 		Message<?> message2 = MessageBuilder.withPayload(123).setHeader("routingHeader", "isNumber").build();
 		this.headerValueRouterWithMappingInput.send(message1);
 		this.headerValueRouterWithMappingInput.send(message2);
 		Message<?> reply1 = this.strings.receive(0);
 		Message<?> reply2 = this.numbers.receive(0);
-		assertNotNull(reply1);
-		assertNotNull(reply2);
-		assertEquals("test", reply1.getPayload());
-		assertEquals(123, reply2.getPayload());
+		assertThat(reply1).isNotNull();
+		assertThat(reply2).isNotNull();
+		assertThat(reply1.getPayload()).isEqualTo("test");
+		assertThat(reply2.getPayload()).isEqualTo(123);
 	}
 
 	@Test // INT-1165
 	public void chainWithSendTimeout() {
 		long sendTimeout = TestUtils.getPropertyValue(this.chainWithSendTimeout, "messagingTemplate.sendTimeout",
 				Long.class);
-		assertEquals(9876, sendTimeout);
+		assertThat(sendTimeout).isEqualTo(9876);
 	}
 
 	@Test //INT-1622
@@ -299,19 +285,19 @@ public class ChainParserTests {
 		Message<?> message = MessageBuilder.withPayload("test").build();
 		this.claimCheckInput.send(message);
 		Message<?> reply = this.claimCheckOutput.receive(0);
-		assertEquals(message.getPayload(), reply.getPayload());
+		assertThat(reply.getPayload()).isEqualTo(message.getPayload());
 	}
 
 	@Test //INT-2275
 	public void chainWithOutboundChannelAdapter() {
 		this.outboundChannelAdapterChannel.send(successMessage);
-		assertSame(successMessage, testConsumer.getLastMessage());
+		assertThat(testConsumer.getLastMessage()).isSameAs(successMessage);
 	}
 
 	@Test //INT-2275, INT-2958
 	public void chainWithLoggingChannelAdapter() {
 		Log logger = mock(Log.class);
-		final AtomicReference<String> log = new AtomicReference<String>();
+		final AtomicReference<String> log = new AtomicReference<>();
 		when(logger.isWarnEnabled()).thenReturn(true);
 		doAnswer(invocation -> {
 			log.set(invocation.getArgument(0));
@@ -321,13 +307,13 @@ public class ChainParserTests {
 		@SuppressWarnings("unchecked")
 		List<MessageHandler> handlers = TestUtils.getPropertyValue(this.logChain, "handlers", List.class);
 		MessageHandler handler = handlers.get(2);
-		assertTrue(handler instanceof LoggingHandler);
+		assertThat(handler instanceof LoggingHandler).isTrue();
 		DirectFieldAccessor dfa = new DirectFieldAccessor(handler);
 		dfa.setPropertyValue("messageLogger", logger);
 
 		this.loggingChannelAdapterChannel.send(MessageBuilder.withPayload(new byte[] { 116, 101, 115, 116 }).build());
-		assertNotNull(log.get());
-		assertEquals("TEST", log.get());
+		assertThat(log.get()).isNotNull();
+		assertThat(log.get()).isEqualTo("TEST");
 	}
 
 	@Test(expected = BeanCreationException.class) //INT-2275
@@ -338,9 +324,9 @@ public class ChainParserTests {
 			fail("BeanCreationException is expected!");
 		}
 		catch (BeansException e) {
-			assertEquals(IllegalArgumentException.class, e.getCause().getClass());
-			assertTrue(e.getMessage().contains("output channel was provided"));
-			assertTrue(e.getMessage().contains("does not implement the MessageProducer"));
+			assertThat(e.getCause().getClass()).isEqualTo(IllegalArgumentException.class);
+			assertThat(e.getMessage()).contains("output channel was provided");
+			assertThat(e.getMessage()).contains("does not implement the MessageProducer");
 			throw e;
 		}
 	}
@@ -350,100 +336,134 @@ public class ChainParserTests {
 		ConfigurableApplicationContext ctx = new ClassPathXmlApplicationContext(
 				"ChainParserSmartLifecycleAttributesTest.xml", this.getClass());
 		AbstractEndpoint chainEndpoint = ctx.getBean("chain", AbstractEndpoint.class);
-		assertEquals(false, chainEndpoint.isAutoStartup());
-		assertEquals(256, chainEndpoint.getPhase());
+		assertThat(chainEndpoint.isAutoStartup()).isEqualTo(false);
+		assertThat(chainEndpoint.getPhase()).isEqualTo(256);
 
 		MessageHandlerChain handlerChain = ctx.getBean("chain.handler", MessageHandlerChain.class);
-		assertEquals(3000L, TestUtils.getPropertyValue(handlerChain, "messagingTemplate.sendTimeout"));
-		assertEquals(false, TestUtils.getPropertyValue(handlerChain, "running"));
+		assertThat(TestUtils.getPropertyValue(handlerChain, "messagingTemplate.sendTimeout")).isEqualTo(3000L);
+		assertThat(TestUtils.getPropertyValue(handlerChain, "running")).isEqualTo(false);
 		//INT-3108
 		MessageHandler serviceActivator = ctx.getBean("chain$child.sa-within-chain.handler", MessageHandler.class);
-		assertTrue(TestUtils.getPropertyValue(serviceActivator, "requiresReply", Boolean.class));
+		assertThat(TestUtils.getPropertyValue(serviceActivator, "requiresReply", Boolean.class)).isTrue();
 		ctx.close();
 	}
 
 	@Test
 	public void testInt2755SubComponentsIdSupport() {
-		assertTrue(this.beanFactory.containsBean("subComponentsIdSupport1.handler"));
-		assertTrue(this.beanFactory.containsBean("filterChain$child.filterWithinChain.handler"));
-		assertTrue(this.beanFactory.containsBean("filterChain$child.serviceActivatorWithinChain.handler"));
-		assertTrue(this.beanFactory.containsBean("aggregatorChain.handler"));
-		assertTrue(this.beanFactory.containsBean("aggregatorChain$child.aggregatorWithinChain.handler"));
-		assertTrue(this.beanFactory.containsBean("aggregatorChain$child.nestedChain.handler"));
-		assertTrue(this.beanFactory.containsBean("aggregatorChain$child.nestedChain$child.filterWithinNestedChain.handler"));
-		assertTrue(this.beanFactory.containsBean("aggregatorChain$child.nestedChain$child.doubleNestedChain.handler"));
-		assertTrue(this.beanFactory.containsBean("aggregatorChain$child.nestedChain$child.doubleNestedChain$child.filterWithinDoubleNestedChain.handler"));
-		assertTrue(this.beanFactory.containsBean("aggregatorChain2.handler"));
-		assertTrue(this.beanFactory.containsBean("aggregatorChain2$child.aggregatorWithinChain.handler"));
-		assertTrue(this.beanFactory.containsBean("aggregatorChain2$child.nestedChain.handler"));
-		assertTrue(this.beanFactory.containsBean("aggregatorChain2$child.nestedChain$child.filterWithinNestedChain.handler"));
-		assertTrue(this.beanFactory.containsBean("payloadTypeRouterChain$child.payloadTypeRouterWithinChain.handler"));
-		assertTrue(this.beanFactory.containsBean("headerValueRouterChain$child.headerValueRouterWithinChain.handler"));
-		assertTrue(this.beanFactory.containsBean("chainWithClaimChecks$child.claimCheckInWithinChain.handler"));
-		assertTrue(this.beanFactory.containsBean("chainWithClaimChecks$child.claimCheckOutWithinChain.handler"));
-		assertTrue(this.beanFactory.containsBean("outboundChain$child.outboundChannelAdapterWithinChain.handler"));
-		assertTrue(this.beanFactory.containsBean("logChain$child.transformerWithinChain.handler"));
-		assertTrue(this.beanFactory.containsBean("logChain$child.loggingChannelAdapterWithinChain.handler"));
-		assertTrue(this.beanFactory.containsBean("subComponentsIdSupport1$child.splitterWithinChain.handler"));
-		assertTrue(this.beanFactory.containsBean("subComponentsIdSupport1$child.resequencerWithinChain.handler"));
-		assertTrue(this.beanFactory.containsBean("subComponentsIdSupport1$child.enricherWithinChain.handler"));
-		assertTrue(this.beanFactory.containsBean("subComponentsIdSupport1$child.headerFilterWithinChain.handler"));
-		assertTrue(this.beanFactory.containsBean("subComponentsIdSupport1$child.payloadSerializingTransformerWithinChain.handler"));
-		assertTrue(this.beanFactory.containsBean("subComponentsIdSupport1$child.payloadDeserializingTransformerWithinChain.handler"));
-		assertTrue(this.beanFactory.containsBean("subComponentsIdSupport1$child.gatewayWithinChain.handler"));
+		assertThat(this.beanFactory.containsBean("subComponentsIdSupport1.handler")).isTrue();
+		assertThat(this.beanFactory.containsBean("filterChain$child.filterWithinChain.handler")).isTrue();
+		assertThat(this.beanFactory.containsBean("filterChain$child.serviceActivatorWithinChain.handler")).isTrue();
+		assertThat(this.beanFactory.containsBean("aggregatorChain.handler")).isTrue();
+		assertThat(this.beanFactory.containsBean("aggregatorChain$child.aggregatorWithinChain.handler")).isTrue();
+		assertThat(this.beanFactory.containsBean("aggregatorChain$child.nestedChain.handler")).isTrue();
+		assertThat(this.beanFactory
+				.containsBean("aggregatorChain$child.nestedChain$child.filterWithinNestedChain.handler")).isTrue();
+		assertThat(this.beanFactory.containsBean("aggregatorChain$child.nestedChain$child.doubleNestedChain.handler"))
+				.isTrue();
+		assertThat(this.beanFactory
+				.containsBean("aggregatorChain$child.nestedChain$child.doubleNestedChain$child" +
+						".filterWithinDoubleNestedChain.handler"))
+				.isTrue();
+		assertThat(this.beanFactory.containsBean("aggregatorChain2.handler")).isTrue();
+		assertThat(this.beanFactory.containsBean("aggregatorChain2$child.aggregatorWithinChain.handler")).isTrue();
+		assertThat(this.beanFactory.containsBean("aggregatorChain2$child.nestedChain.handler")).isTrue();
+		assertThat(this.beanFactory
+				.containsBean("aggregatorChain2$child.nestedChain$child.filterWithinNestedChain.handler")).isTrue();
+		assertThat(this.beanFactory.containsBean("payloadTypeRouterChain$child.payloadTypeRouterWithinChain.handler"))
+				.isTrue();
+		assertThat(this.beanFactory.containsBean("headerValueRouterChain$child.headerValueRouterWithinChain.handler"))
+				.isTrue();
+		assertThat(this.beanFactory.containsBean("chainWithClaimChecks$child.claimCheckInWithinChain.handler"))
+				.isTrue();
+		assertThat(this.beanFactory.containsBean("chainWithClaimChecks$child.claimCheckOutWithinChain.handler"))
+				.isTrue();
+		assertThat(this.beanFactory.containsBean("outboundChain$child.outboundChannelAdapterWithinChain.handler"))
+				.isTrue();
+		assertThat(this.beanFactory.containsBean("logChain$child.transformerWithinChain.handler")).isTrue();
+		assertThat(this.beanFactory.containsBean("logChain$child.loggingChannelAdapterWithinChain.handler")).isTrue();
+		assertThat(this.beanFactory.containsBean("subComponentsIdSupport1$child.splitterWithinChain.handler")).isTrue();
+		assertThat(this.beanFactory.containsBean("subComponentsIdSupport1$child.resequencerWithinChain.handler"))
+				.isTrue();
+		assertThat(this.beanFactory.containsBean("subComponentsIdSupport1$child.enricherWithinChain.handler")).isTrue();
+		assertThat(this.beanFactory.containsBean("subComponentsIdSupport1$child.headerFilterWithinChain.handler"))
+				.isTrue();
+		assertThat(this.beanFactory
+				.containsBean("subComponentsIdSupport1$child.payloadSerializingTransformerWithinChain.handler"))
+				.isTrue();
+		assertThat(this.beanFactory
+				.containsBean("subComponentsIdSupport1$child.payloadDeserializingTransformerWithinChain.handler"))
+				.isTrue();
+		assertThat(this.beanFactory.containsBean("subComponentsIdSupport1$child.gatewayWithinChain.handler")).isTrue();
 		//INT-3117
-		GatewayProxyFactoryBean gatewayProxyFactoryBean = this.beanFactory.getBean("&subComponentsIdSupport1$child.gatewayWithinChain.handler",
+		GatewayProxyFactoryBean gatewayProxyFactoryBean = this.beanFactory.getBean("&subComponentsIdSupport1$child" +
+						".gatewayWithinChain.handler",
 				GatewayProxyFactoryBean.class);
-		assertEquals("strings", TestUtils.getPropertyValue(gatewayProxyFactoryBean, "defaultRequestChannelName"));
-		assertEquals("numbers", TestUtils.getPropertyValue(gatewayProxyFactoryBean, "defaultReplyChannelName"));
-		assertEquals(1000L, TestUtils
-				.getPropertyValue(gatewayProxyFactoryBean, "defaultRequestTimeout", Expression.class).getValue());
-		assertEquals(100L, TestUtils
-				.getPropertyValue(gatewayProxyFactoryBean, "defaultReplyTimeout", Expression.class).getValue());
+		assertThat(TestUtils.getPropertyValue(gatewayProxyFactoryBean, "defaultRequestChannelName"))
+				.isEqualTo("strings");
+		assertThat(TestUtils.getPropertyValue(gatewayProxyFactoryBean, "defaultReplyChannelName")).isEqualTo(
+				"numbers");
+		assertThat(TestUtils
+				.getPropertyValue(gatewayProxyFactoryBean, "defaultRequestTimeout", Expression.class).getValue())
+				.isEqualTo(1000L);
+		assertThat(TestUtils
+				.getPropertyValue(gatewayProxyFactoryBean, "defaultReplyTimeout", Expression.class).getValue())
+				.isEqualTo(100L);
 
-		assertTrue(this.beanFactory.containsBean("subComponentsIdSupport1$child.objectToStringTransformerWithinChain.handler"));
-		assertTrue(this.beanFactory.containsBean("subComponentsIdSupport1$child.objectToMapTransformerWithinChain.handler"));
+		assertThat(this.beanFactory
+				.containsBean("subComponentsIdSupport1$child.objectToStringTransformerWithinChain.handler")).isTrue();
+		assertThat(this.beanFactory
+				.containsBean("subComponentsIdSupport1$child.objectToMapTransformerWithinChain.handler")).isTrue();
 
-		Object transformerHandler = this.beanFactory.getBean("subComponentsIdSupport1$child.objectToMapTransformerWithinChain.handler");
+		Object transformerHandler = this.beanFactory.getBean(
+				"subComponentsIdSupport1$child.objectToMapTransformerWithinChain.handler");
 
 		Object transformer = TestUtils.getPropertyValue(transformerHandler, "transformer");
 
-		assertThat(transformer, instanceOf(ObjectToMapTransformer.class));
-		assertFalse(TestUtils.getPropertyValue(transformer, "shouldFlattenKeys", Boolean.class));
-		assertSame(this.beanFactory.getBean(JsonObjectMapper.class),
-				TestUtils.getPropertyValue(transformer, "jsonObjectMapper"));
+		assertThat(transformer).isInstanceOf(ObjectToMapTransformer.class);
+		assertThat(TestUtils.getPropertyValue(transformer, "shouldFlattenKeys", Boolean.class)).isFalse();
+		assertThat(TestUtils.getPropertyValue(transformer, "jsonObjectMapper"))
+				.isSameAs(this.beanFactory.getBean(JsonObjectMapper.class));
 
-		assertTrue(this.beanFactory.containsBean("subComponentsIdSupport1$child.mapToObjectTransformerWithinChain.handler"));
-		assertTrue(this.beanFactory.containsBean("subComponentsIdSupport1$child.controlBusWithinChain.handler"));
-		assertTrue(this.beanFactory.containsBean("subComponentsIdSupport1$child.routerWithinChain.handler"));
-		assertTrue(this.beanFactory.containsBean("exceptionTypeRouterChain$child.exceptionTypeRouterWithinChain.handler"));
-		assertTrue(this.beanFactory.containsBean("recipientListRouterChain$child.recipientListRouterWithinChain.handler"));
+		assertThat(this.beanFactory
+				.containsBean("subComponentsIdSupport1$child.mapToObjectTransformerWithinChain.handler")).isTrue();
+		assertThat(this.beanFactory.containsBean("subComponentsIdSupport1$child.controlBusWithinChain.handler"))
+				.isTrue();
+		assertThat(this.beanFactory.containsBean("subComponentsIdSupport1$child.routerWithinChain.handler")).isTrue();
+		assertThat(this.beanFactory
+				.containsBean("exceptionTypeRouterChain$child.exceptionTypeRouterWithinChain.handler")).isTrue();
+		assertThat(this.beanFactory
+				.containsBean("recipientListRouterChain$child.recipientListRouterWithinChain.handler")).isTrue();
 
 		MessageHandlerChain chain = this.beanFactory.getBean("headerEnricherChain.handler", MessageHandlerChain.class);
 		List<?> handlers = TestUtils.getPropertyValue(chain, "handlers", List.class);
 
-		assertTrue(handlers.get(0) instanceof MessageTransformingHandler);
-		assertEquals("headerEnricherChain$child.headerEnricherWithinChain", TestUtils.getPropertyValue(handlers.get(0), "componentName"));
-		assertEquals("headerEnricherChain$child.headerEnricherWithinChain.handler", TestUtils.getPropertyValue(handlers.get(0), "beanName"));
-		assertTrue(this.beanFactory.containsBean("headerEnricherChain$child.headerEnricherWithinChain.handler"));
+		assertThat(handlers.get(0) instanceof MessageTransformingHandler).isTrue();
+		assertThat(TestUtils.getPropertyValue(handlers.get(0), "componentName"))
+				.isEqualTo("headerEnricherChain$child.headerEnricherWithinChain");
+		assertThat(TestUtils.getPropertyValue(handlers.get(0), "beanName"))
+				.isEqualTo("headerEnricherChain$child.headerEnricherWithinChain.handler");
+		assertThat(this.beanFactory.containsBean("headerEnricherChain$child.headerEnricherWithinChain.handler"))
+				.isTrue();
 
-		assertTrue(handlers.get(1) instanceof ServiceActivatingHandler);
-		assertEquals("headerEnricherChain$child#1", TestUtils.getPropertyValue(handlers.get(1), "componentName"));
-		assertEquals("headerEnricherChain$child#1.handler", TestUtils.getPropertyValue(handlers.get(1), "beanName"));
-		assertFalse(this.beanFactory.containsBean("headerEnricherChain$child#1.handler"));
+		assertThat(handlers.get(1) instanceof ServiceActivatingHandler).isTrue();
+		assertThat(TestUtils.getPropertyValue(handlers.get(1), "componentName"))
+				.isEqualTo("headerEnricherChain$child#1");
+		assertThat(TestUtils.getPropertyValue(handlers.get(1), "beanName"))
+				.isEqualTo("headerEnricherChain$child#1.handler");
+		assertThat(this.beanFactory.containsBean("headerEnricherChain$child#1.handler")).isFalse();
 
 	}
 
 	@Test
 	public void testInt2755SubComponentException() {
-		GenericMessage<String> testMessage = new GenericMessage<String>("test");
+		GenericMessage<String> testMessage = new GenericMessage<>("test");
 		try {
 			this.chainReplyRequiredChannel.send(testMessage);
 			fail("Expected ReplyRequiredException");
 		}
 		catch (Exception e) {
-			assertTrue(e instanceof ReplyRequiredException);
-			assertTrue(e.getMessage().contains("'chainReplyRequired$child.transformerReplyRequired'"));
+			assertThat(e instanceof ReplyRequiredException).isTrue();
+			assertThat(e.getMessage().contains("'chainReplyRequired$child.transformerReplyRequired'")).isTrue();
 		}
 
 		try {
@@ -451,8 +471,9 @@ public class ChainParserTests {
 			fail("Expected MessageRejectedException");
 		}
 		catch (Exception e) {
-			assertTrue(e instanceof MessageRejectedException);
-			assertTrue(e.getMessage().contains("chainMessageRejectedException$child.filterMessageRejectedException"));
+			assertThat(e instanceof MessageRejectedException).isTrue();
+			assertThat(e.getMessage().contains("chainMessageRejectedException$child.filterMessageRejectedException"))
+					.isTrue();
 		}
 
 	}
@@ -463,13 +484,13 @@ public class ChainParserTests {
 		Message<String> message = MessageBuilder.withPayload("foo").setHeader("myReplyChannel", replyChannel).build();
 		this.chainWithNoOutputChannel.send(message);
 		Message<?> receive = replyChannel.receive(10000);
-		assertNotNull(receive);
+		assertThat(receive).isNotNull();
 
 		message = MessageBuilder.withPayload("foo").setReplyChannel(replyChannel).build();
 		Message<String> message2 = MessageBuilder.withPayload("bar").setHeader("myMessage", message).build();
 		this.chainWithTransformNoOutputChannel.send(message2);
 		receive = replyChannel.receive(10000);
-		assertNotNull(receive);
+		assertThat(receive).isNotNull();
 	}
 
 	public static class StubHandler extends AbstractReplyProducingMessageHandler {
@@ -486,6 +507,7 @@ public class ChainParserTests {
 		public String aggregate(List<String> strings) {
 			return StringUtils.collectionToCommaDelimitedString(strings);
 		}
+
 	}
 
 	public static class FooPojo {

spring-integration-core/src/test/java/org/springframework/integration/config/ChannelAdapterParserTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2016 the original author or authors.
+ * Copyright 2002-2019 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -16,16 +16,9 @@
 
 package org.springframework.integration.config;
 
-import static org.junit.Assert.assertEquals;
-import static org.junit.Assert.assertFalse;
-import static org.junit.Assert.assertNotNull;
-import static org.junit.Assert.assertNull;
-import static org.junit.Assert.assertSame;
-import static org.junit.Assert.assertThat;
-import static org.junit.Assert.assertTrue;
-import static org.junit.Assert.fail;
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.assertj.core.api.Assertions.fail;
 
-import org.hamcrest.Matchers;
 import org.junit.After;
 import org.junit.Before;
 import org.junit.Test;
@@ -81,16 +74,16 @@ public class ChannelAdapterParserTests {
 		TestBean testBean = (TestBean) this.applicationContext.getBean("testBean");
 		testBean.store("source test");
 		Object adapter = this.applicationContext.getBean(beanName);
-		assertNotNull(adapter);
-		assertTrue(adapter instanceof SourcePollingChannelAdapter);
-		assertEquals(-1, ((SourcePollingChannelAdapter) adapter).getPhase());
+		assertThat(adapter).isNotNull();
+		assertThat(adapter instanceof SourcePollingChannelAdapter).isTrue();
+		assertThat(((SourcePollingChannelAdapter) adapter).getPhase()).isEqualTo(-1);
 		this.applicationContext.start();
 		Message<?> message = channel.receive(10000);
-		assertNotNull(message);
-		assertEquals("source test", testBean.getMessage());
+		assertThat(message).isNotNull();
+		assertThat(testBean.getMessage()).isEqualTo("source test");
 		this.applicationContext.stop();
 		message = channel.receive(100);
-		assertNull(message);
+		assertThat(message).isNull();
 	}
 
 	@Test
@@ -100,63 +93,63 @@ public class ChannelAdapterParserTests {
 //		TestBean testBean = (TestBean) this.applicationContextInner.getBean("testBean");
 //		testBean.store("source test");
 		Object adapter = this.applicationContextInner.getBean(beanName);
-		assertNotNull(adapter);
-		assertTrue(adapter instanceof SourcePollingChannelAdapter);
+		assertThat(adapter).isNotNull();
+		assertThat(adapter instanceof SourcePollingChannelAdapter).isTrue();
 		this.applicationContextInner.start();
 		Message<?> message = channel.receive(10000);
-		assertNotNull(message);
+		assertThat(message).isNotNull();
 		//assertEquals("source test", testBean.getMessage());
 		this.applicationContextInner.stop();
 		message = channel.receive(100);
-		assertNull(message);
+		assertThat(message).isNull();
 	}
 
 	@Test
 	public void targetOnly() {
 		String beanName = "outboundWithImplicitChannel";
 		Object channel = this.applicationContext.getBean(beanName);
-		assertTrue(channel instanceof DirectChannel);
+		assertThat(channel instanceof DirectChannel).isTrue();
 		BeanFactoryChannelResolver channelResolver = new BeanFactoryChannelResolver(this.applicationContext);
-		assertNotNull(channelResolver.resolveDestination(beanName));
+		assertThat(channelResolver.resolveDestination(beanName)).isNotNull();
 		Object adapter = this.applicationContext.getBean(beanName + ".adapter");
-		assertNotNull(adapter);
-		assertTrue(adapter instanceof EventDrivenConsumer);
-		assertFalse(((EventDrivenConsumer) adapter).isAutoStartup());
-		assertEquals(-1, ((EventDrivenConsumer) adapter).getPhase());
+		assertThat(adapter).isNotNull();
+		assertThat(adapter instanceof EventDrivenConsumer).isTrue();
+		assertThat(((EventDrivenConsumer) adapter).isAutoStartup()).isFalse();
+		assertThat(((EventDrivenConsumer) adapter).getPhase()).isEqualTo(-1);
 		TestConsumer consumer = (TestConsumer) this.applicationContext.getBean("consumer");
-		assertNull(consumer.getLastMessage());
+		assertThat(consumer.getLastMessage()).isNull();
 		Message<?> message = new GenericMessage<String>("test");
 		try {
 			((MessageChannel) channel).send(message);
 			fail("MessageDispatchingException is expected.");
 		}
 		catch (Exception e) {
-			assertThat(e, Matchers.instanceOf(MessageDeliveryException.class));
-			assertThat(e.getCause(), Matchers.instanceOf(MessageDispatchingException.class));
+			assertThat(e).isInstanceOf(MessageDeliveryException.class);
+			assertThat(e.getCause()).isInstanceOf(MessageDispatchingException.class);
 		}
 
 		((EventDrivenConsumer) adapter).start();
 		((MessageChannel) channel).send(message);
-		assertNotNull(consumer.getLastMessage());
-		assertEquals(message, consumer.getLastMessage());
+		assertThat(consumer.getLastMessage()).isNotNull();
+		assertThat(consumer.getLastMessage()).isEqualTo(message);
 	}
 
 	@Test
 	public void methodInvokingConsumer() {
 		String beanName = "methodInvokingConsumer";
 		Object channel = this.applicationContext.getBean(beanName);
-		assertTrue(channel instanceof DirectChannel);
+		assertThat(channel instanceof DirectChannel).isTrue();
 		BeanFactoryChannelResolver channelResolver = new BeanFactoryChannelResolver(this.applicationContext);
-		assertNotNull(channelResolver.resolveDestination(beanName));
+		assertThat(channelResolver.resolveDestination(beanName)).isNotNull();
 		Object adapter = this.applicationContext.getBean(beanName + ".adapter");
-		assertNotNull(adapter);
-		assertTrue(adapter instanceof EventDrivenConsumer);
+		assertThat(adapter).isNotNull();
+		assertThat(adapter instanceof EventDrivenConsumer).isTrue();
 		TestBean testBean = (TestBean) this.applicationContext.getBean("testBean");
-		assertNull(testBean.getMessage());
+		assertThat(testBean.getMessage()).isNull();
 		Message<?> message = new GenericMessage<String>("consumer test");
-		assertTrue(((MessageChannel) channel).send(message));
-		assertNotNull(testBean.getMessage());
-		assertEquals("consumer test", testBean.getMessage());
+		assertThat(((MessageChannel) channel).send(message)).isTrue();
+		assertThat(testBean.getMessage()).isNotNull();
+		assertThat(testBean.getMessage()).isEqualTo("consumer test");
 	}
 
 	@Test
@@ -166,18 +159,18 @@ public class ChannelAdapterParserTests {
 	public void expressionConsumer() {
 		String beanName = "expressionConsumer";
 		Object channel = this.applicationContext.getBean(beanName);
-		assertTrue(channel instanceof DirectChannel);
+		assertThat(channel instanceof DirectChannel).isTrue();
 		BeanFactoryChannelResolver channelResolver = new BeanFactoryChannelResolver(this.applicationContext);
-		assertNotNull(channelResolver.resolveDestination(beanName));
+		assertThat(channelResolver.resolveDestination(beanName)).isNotNull();
 		Object adapter = this.applicationContext.getBean(beanName + ".adapter");
-		assertNotNull(adapter);
-		assertTrue(adapter instanceof EventDrivenConsumer);
+		assertThat(adapter).isNotNull();
+		assertThat(adapter instanceof EventDrivenConsumer).isTrue();
 		TestBean testBean = (TestBean) this.applicationContext.getBean("testBean");
-		assertNull(testBean.getMessage());
+		assertThat(testBean.getMessage()).isNull();
 		Message<?> message = new GenericMessage<String>("consumer test expression");
-		assertTrue(((MessageChannel) channel).send(message));
-		assertNotNull(testBean.getMessage());
-		assertEquals("consumer test expression", testBean.getMessage());
+		assertThat(((MessageChannel) channel).send(message)).isTrue();
+		assertThat(testBean.getMessage()).isNotNull();
+		assertThat(testBean.getMessage()).isEqualTo("consumer test expression");
 	}
 
 	@Test
@@ -187,12 +180,12 @@ public class ChannelAdapterParserTests {
 		TestBean testBean = (TestBean) this.applicationContext.getBean("testBean");
 		testBean.store("source test");
 		Object adapter = this.applicationContext.getBean(beanName);
-		assertNotNull(adapter);
-		assertTrue(adapter instanceof SourcePollingChannelAdapter);
+		assertThat(adapter).isNotNull();
+		assertThat(adapter instanceof SourcePollingChannelAdapter).isTrue();
 		((SourcePollingChannelAdapter) adapter).start();
 		Message<?> message = channel.receive(10000);
-		assertNotNull(message);
-		assertEquals("source test", testBean.getMessage());
+		assertThat(message).isNotNull();
+		assertThat(testBean.getMessage()).isEqualTo("source test");
 		((SourcePollingChannelAdapter) adapter).stop();
 	}
 
@@ -203,16 +196,16 @@ public class ChannelAdapterParserTests {
 		TestBean testBean = (TestBean) this.applicationContext.getBean("testBean");
 		testBean.store("source test");
 		Object adapter = this.applicationContext.getBean(beanName);
-		assertNotNull(adapter);
-		assertTrue(adapter instanceof SourcePollingChannelAdapter);
+		assertThat(adapter).isNotNull();
+		assertThat(adapter instanceof SourcePollingChannelAdapter).isTrue();
 		((SourcePollingChannelAdapter) adapter).start();
 		Message<?> message = channel.receive(10000);
 		((SourcePollingChannelAdapter) adapter).stop();
-		assertNotNull(message);
-		assertEquals("source test", testBean.getMessage());
-		assertEquals("source test", message.getPayload());
-		assertEquals("ABC", message.getHeaders().get("foo"));
-		assertEquals(123, message.getHeaders().get("bar"));
+		assertThat(message).isNotNull();
+		assertThat(testBean.getMessage()).isEqualTo("source test");
+		assertThat(message.getPayload()).isEqualTo("source test");
+		assertThat(message.getHeaders().get("foo")).isEqualTo("ABC");
+		assertThat(message.getHeaders().get("bar")).isEqualTo(123);
 	}
 
 	@Test
@@ -222,10 +215,10 @@ public class ChannelAdapterParserTests {
 		TestBean testBean = (TestBean) this.applicationContext.getBean("testBean");
 		testBean.store("source test");
 		Object adapter = this.applicationContext.getBean(beanName);
-		assertNotNull(adapter);
-		assertTrue(adapter instanceof SourcePollingChannelAdapter);
+		assertThat(adapter).isNotNull();
+		assertThat(adapter instanceof SourcePollingChannelAdapter).isTrue();
 		Message<?> message = channel.receive(100);
-		assertNull(message);
+		assertThat(message).isNull();
 	}
 
 	@Test
@@ -235,15 +228,15 @@ public class ChannelAdapterParserTests {
 		TestBean testBean = (TestBean) this.applicationContext.getBean("testBean");
 		testBean.store("source test");
 		Object adapter = this.applicationContext.getBean(beanName);
-		assertNotNull(adapter);
-		assertTrue(adapter instanceof SourcePollingChannelAdapter);
+		assertThat(adapter).isNotNull();
+		assertThat(adapter instanceof SourcePollingChannelAdapter).isTrue();
 		((SourcePollingChannelAdapter) adapter).start();
 		Message<?> message = channel.receive(10000);
-		assertNotNull(message);
-		assertEquals("source test", testBean.getMessage());
+		assertThat(message).isNotNull();
+		assertThat(testBean.getMessage()).isEqualTo("source test");
 		((SourcePollingChannelAdapter) adapter).stop();
 		message = channel.receive(100);
-		assertNull(message);
+		assertThat(message).isNull();
 	}
 
 	@Test
@@ -253,12 +246,12 @@ public class ChannelAdapterParserTests {
 		TestBean testBean = (TestBean) this.applicationContext.getBean("testBean");
 		testBean.store("source test");
 		Object adapter = this.applicationContext.getBean(beanName);
-		assertNotNull(adapter);
-		assertTrue(adapter instanceof SourcePollingChannelAdapter);
+		assertThat(adapter).isNotNull();
+		assertThat(adapter instanceof SourcePollingChannelAdapter).isTrue();
 		this.applicationContext.start();
 		Message<?> message = channel.receive(1000);
-		assertNotNull(message);
-		assertEquals("source test", testBean.getMessage());
+		assertThat(message).isNotNull();
+		assertThat(testBean.getMessage()).isEqualTo("source test");
 		this.applicationContext.stop();
 	}
 
@@ -274,9 +267,9 @@ public class ChannelAdapterParserTests {
 
 		SourcePollingChannelAdapter adapter =
 				this.applicationContext.getBean(beanName, SourcePollingChannelAdapter.class);
-		assertNotNull(adapter);
+		assertThat(adapter).isNotNull();
 		long sendTimeout = TestUtils.getPropertyValue(adapter, "messagingTemplate.sendTimeout", Long.class);
-		assertEquals(999, sendTimeout);
+		assertThat(sendTimeout).isEqualTo(999);
 	}
 
 	@Test(expected = BeanDefinitionParsingException.class)
@@ -292,11 +285,11 @@ public class ChannelAdapterParserTests {
 
 		for (int i = 0; i < 10; i++) {
 			Message<?> message = channel1.receive(5000);
-			assertNotNull(message);
-			assertEquals(i + 1, message.getPayload());
+			assertThat(message).isNotNull();
+			assertThat(message.getPayload()).isEqualTo(i + 1);
 			message = channel2.receive(5000);
-			assertNotNull(message);
-			assertEquals(i + 1, message.getPayload());
+			assertThat(message).isNotNull();
+			assertThat(message.getPayload()).isEqualTo(i + 1);
 		}
 	}
 
@@ -305,14 +298,14 @@ public class ChannelAdapterParserTests {
 		PollableChannel channel = this.applicationContext.getBean("messageSourceRefChannel", PollableChannel.class);
 
 		Message<?> message = channel.receive(5000);
-		assertNotNull(message);
-		assertEquals("test", message.getPayload());
+		assertThat(message).isNotNull();
+		assertThat(message.getPayload()).isEqualTo("test");
 
 		MessageSource<?> testMessageSource = this.applicationContext.getBean("testMessageSource", MessageSource.class);
 		SourcePollingChannelAdapter adapterWithMessageSourceRef =
 				this.applicationContext.getBean("adapterWithMessageSourceRef", SourcePollingChannelAdapter.class);
 		MessageSource<?> source = TestUtils.getPropertyValue(adapterWithMessageSourceRef, "source", MessageSource.class);
-		assertSame(testMessageSource, source);
+		assertThat(source).isSameAs(testMessageSource);
 	}
 
 	public static class SampleBean {

spring-integration-core/src/test/java/org/springframework/integration/config/ChannelWithMessageStoreParserTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2016 the original author or authors.
+ * Copyright 2002-2019 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -16,10 +16,7 @@
 
 package org.springframework.integration.config;
 
-import static org.hamcrest.Matchers.instanceOf;
-import static org.junit.Assert.assertEquals;
-import static org.junit.Assert.assertSame;
-import static org.junit.Assert.assertThat;
+import static org.assertj.core.api.Assertions.assertThat;
 
 import java.util.concurrent.TimeUnit;
 
@@ -79,21 +76,22 @@ public class ChannelWithMessageStoreParserTests {
 
 		input.send(createMessage("123", "id1", 3, 1, null));
 		handler.getLatch().await(100, TimeUnit.MILLISECONDS);
-		assertEquals("The message payload is not correct", "123", handler.getMessageString());
+		assertThat(handler.getMessageString()).as("The message payload is not correct").isEqualTo("123");
 		// The group id for buffered messages is the channel name
-		assertEquals(1, messageGroupStore.getMessageGroup("messageStore:output").size());
+		assertThat(messageGroupStore.getMessageGroup("messageStore:output").size()).isEqualTo(1);
 
 		Message<?> result = output.receive(100);
-		assertEquals("hello", result.getPayload());
-		assertEquals(0, messageGroupStore.getMessageGroup(BASE_PACKAGE + ".store:output").size());
+		assertThat(result.getPayload()).isEqualTo("hello");
+		assertThat(messageGroupStore.getMessageGroup(BASE_PACKAGE + ".store:output").size()).isEqualTo(0);
 
 	}
 
 	@Test
 	@DirtiesContext
 	public void testPriorityMessageStore() {
-		assertSame(this.priorityMessageStore, TestUtils.getPropertyValue(this.priorityChannel, "queue.messageGroupStore"));
-		assertThat(this.priorityChannel, instanceOf(PriorityChannel.class));
+		assertThat(TestUtils.getPropertyValue(this.priorityChannel, "queue.messageGroupStore"))
+				.isSameAs(this.priorityMessageStore);
+		assertThat(this.priorityChannel).isInstanceOf(PriorityChannel.class);
 	}
 
 	private static <T> Message<T> createMessage(T payload, Object correlationId, int sequenceSize, int sequenceNumber,

spring-integration-core/src/test/java/org/springframework/integration/config/CorrelationStrategyInvalidConfigurationTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2015 the original author or authors.
+ * Copyright 2002-2019 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -16,8 +16,7 @@
 
 package org.springframework.integration.config;
 
-import static org.hamcrest.Matchers.containsString;
-import static org.junit.Assert.assertThat;
+import static org.assertj.core.api.Assertions.assertThat;
 
 import org.junit.Test;
 
@@ -37,7 +36,7 @@ public class CorrelationStrategyInvalidConfigurationTests {
 					CorrelationStrategyInvalidConfigurationTests.class).close();
 		}
 		catch (BeanCreationException e) {
-			assertThat(e.getMessage(), containsString("MessageCountReleaseStrategy] has no eligible methods"));
+			assertThat(e.getMessage()).contains("MessageCountReleaseStrategy] has no eligible methods");
 		}
 	}
 

spring-integration-core/src/test/java/org/springframework/integration/config/EndpointParserTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2017 the original author or authors.
+ * Copyright 2002-2019 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -16,9 +16,7 @@
 
 package org.springframework.integration.config;
 
-import static org.junit.Assert.assertEquals;
-import static org.junit.Assert.assertNull;
-import static org.junit.Assert.assertTrue;
+import static org.assertj.core.api.Assertions.assertThat;
 
 import java.util.concurrent.TimeUnit;
 
@@ -42,10 +40,10 @@ public class EndpointParserTests {
 		context.start();
 		MessageChannel channel = (MessageChannel) context.getBean("endpointParserTestInput");
 		TestHandler handler = (TestHandler) context.getBean("testHandler");
-		assertNull(handler.getMessageString());
+		assertThat(handler.getMessageString()).isNull();
 		channel.send(new GenericMessage<>("test"));
-		assertTrue(handler.getLatch().await(10000, TimeUnit.MILLISECONDS));
-		assertEquals("test", handler.getMessageString());
+		assertThat(handler.getLatch().await(10000, TimeUnit.MILLISECONDS)).isTrue();
+		assertThat(handler.getMessageString()).isEqualTo("test");
 		context.close();
 	}
 

spring-integration-core/src/test/java/org/springframework/integration/config/FilterParserTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2018 the original author or authors.
+ * Copyright 2002-2019 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -16,11 +16,7 @@
 
 package org.springframework.integration.config;
 
-import static org.junit.Assert.assertEquals;
-import static org.junit.Assert.assertFalse;
-import static org.junit.Assert.assertNotNull;
-import static org.junit.Assert.assertNull;
-import static org.junit.Assert.assertTrue;
+import static org.assertj.core.api.Assertions.assertThat;
 
 import org.junit.Test;
 import org.junit.runner.RunWith;
@@ -97,8 +93,8 @@ public class FilterParserTests {
 
 	@Test
 	public void adviseDiscard() {
-		assertFalse(TestUtils.getPropertyValue(this.advised, "postProcessWithinAdvice", Boolean.class));
-		assertTrue(TestUtils.getPropertyValue(this.notAdvised, "postProcessWithinAdvice", Boolean.class));
+		assertThat(TestUtils.getPropertyValue(this.advised, "postProcessWithinAdvice", Boolean.class)).isFalse();
+		assertThat(TestUtils.getPropertyValue(this.notAdvised, "postProcessWithinAdvice", Boolean.class)).isTrue();
 	}
 
 	@Test
@@ -106,38 +102,38 @@ public class FilterParserTests {
 		adviceCalled = 0;
 		adapterInput.send(new GenericMessage<>("test"));
 		Message<?> reply = adapterOutput.receive(0);
-		assertNotNull(reply);
-		assertEquals("test", reply.getPayload());
-		assertEquals(1, adviceCalled);
+		assertThat(reply).isNotNull();
+		assertThat(reply.getPayload()).isEqualTo("test");
+		assertThat(adviceCalled).isEqualTo(1);
 	}
 
 	@Test
 	public void filterWithSelectorAdapterRejects() {
 		adapterInput.send(new GenericMessage<>(""));
 		Message<?> reply = adapterOutput.receive(0);
-		assertNull(reply);
+		assertThat(reply).isNull();
 	}
 
 	@Test
 	public void filterWithSelectorImplementationAccepts() {
 		implementationInput.send(new GenericMessage<>("test"));
 		Message<?> reply = implementationOutput.receive(0);
-		assertNotNull(reply);
-		assertEquals("test", reply.getPayload());
+		assertThat(reply).isNotNull();
+		assertThat(reply.getPayload()).isEqualTo("test");
 	}
 
 	@Test
 	public void filterWithSelectorImplementationRejects() {
 		implementationInput.send(new GenericMessage<>(""));
 		Message<?> reply = implementationOutput.receive(0);
-		assertNull(reply);
+		assertThat(reply).isNull();
 	}
 
 	@Test
 	public void exceptionThrowingFilterAccepts() {
 		exceptionInput.send(new GenericMessage<>("test"));
 		Message<?> reply = implementationOutput.receive(0);
-		assertNotNull(reply);
+		assertThat(reply).isNotNull();
 	}
 
 	@Test(expected = MessageRejectedException.class)
@@ -149,9 +145,9 @@ public class FilterParserTests {
 	public void filterWithDiscardChannel() {
 		discardInput.send(new GenericMessage<>(""));
 		Message<?> discard = discardOutput.receive(0);
-		assertNotNull(discard);
-		assertEquals("", discard.getPayload());
-		assertNull(adapterOutput.receive(0));
+		assertThat(discard).isNotNull();
+		assertThat(discard.getPayload()).isEqualTo("");
+		assertThat(adapterOutput.receive(0)).isNull();
 	}
 
 	@Test(expected = MessageRejectedException.class)
@@ -164,9 +160,9 @@ public class FilterParserTests {
 			exception = e;
 		}
 		Message<?> discard = discardAndExceptionOutput.receive(0);
-		assertNotNull(discard);
-		assertEquals("", discard.getPayload());
-		assertNull(adapterOutput.receive(0));
+		assertThat(discard).isNotNull();
+		assertThat(discard.getPayload()).isEqualTo("");
+		assertThat(adapterOutput.receive(0)).isNull();
 		throw exception;
 	}
 

spring-integration-core/src/test/java/org/springframework/integration/config/IdGeneratorConfigurerTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2016 the original author or authors.
+ * Copyright 2002-2019 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -16,11 +16,8 @@
 
 package org.springframework.integration.config;
 
-import static org.junit.Assert.assertEquals;
-import static org.junit.Assert.assertNotEquals;
-import static org.junit.Assert.assertNull;
-import static org.junit.Assert.assertSame;
-import static org.junit.Assert.fail;
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.assertj.core.api.Assertions.fail;
 
 import java.util.UUID;
 import java.util.concurrent.atomic.AtomicLong;
@@ -50,13 +47,13 @@ public class IdGeneratorConfigurerTests {
 		context.registerBeanDefinition("foo", new RootBeanDefinition(MyIdGenerator.class));
 		context.refresh();
 		MessageHeaders headers = new MessageHeaders(null);
-		assertEquals(1, headers.getId().getMostSignificantBits());
-		assertEquals(2, headers.getId().getLeastSignificantBits());
+		assertThat(headers.getId().getMostSignificantBits()).isEqualTo(1);
+		assertThat(headers.getId().getLeastSignificantBits()).isEqualTo(2);
 		context.close();
 		headers = new MessageHeaders(null);
-		assertNotEquals(1, headers.getId().getMostSignificantBits());
-		assertNotEquals(2, headers.getId().getLeastSignificantBits());
-		assertNull(TestUtils.getPropertyValue(headers, "idGenerator"));
+		assertThat(headers.getId().getMostSignificantBits()).isNotEqualTo(1);
+		assertThat(headers.getId().getLeastSignificantBits()).isNotEqualTo(2);
+		assertThat(TestUtils.getPropertyValue(headers, "idGenerator")).isNull();
 	}
 
 	@Test
@@ -69,7 +66,7 @@ public class IdGeneratorConfigurerTests {
 
 		// multiple beans are ignored with warning
 		MessageHeaders headers = new MessageHeaders(null);
-		assertNull(TestUtils.getPropertyValue(headers, "idGenerator"));
+		assertThat(TestUtils.getPropertyValue(headers, "idGenerator")).isNull();
 
 		context.close();
 	}
@@ -81,7 +78,7 @@ public class IdGeneratorConfigurerTests {
 		context.refresh();
 
 		MessageHeaders headers = new MessageHeaders(null);
-		assertNull(TestUtils.getPropertyValue(headers, "idGenerator"));
+		assertThat(TestUtils.getPropertyValue(headers, "idGenerator")).isNull();
 
 		context.close();
 	}
@@ -93,8 +90,8 @@ public class IdGeneratorConfigurerTests {
 		context.registerBeanDefinition("foo", new RootBeanDefinition(MyIdGenerator.class));
 		context.refresh();
 		MessageHeaders headers = new MessageHeaders(null);
-		assertEquals(1, headers.getId().getMostSignificantBits());
-		assertEquals(2, headers.getId().getLeastSignificantBits());
+		assertThat(headers.getId().getMostSignificantBits()).isEqualTo(1);
+		assertThat(headers.getId().getLeastSignificantBits()).isEqualTo(2);
 
 		GenericApplicationContext context2 = new GenericApplicationContext();
 		context2.registerBeanDefinition("bfpp", new RootBeanDefinition(DefaultConfiguringBeanFactoryPostProcessor.class));
@@ -105,10 +102,10 @@ public class IdGeneratorConfigurerTests {
 		context2.close();
 
 		headers = new MessageHeaders(null);
-		assertNotEquals(1, headers.getId().getMostSignificantBits());
-		assertNotEquals(2, headers.getId().getLeastSignificantBits());
+		assertThat(headers.getId().getMostSignificantBits()).isNotEqualTo(1);
+		assertThat(headers.getId().getLeastSignificantBits()).isNotEqualTo(2);
 
-		assertNull(TestUtils.getPropertyValue(headers, "idGenerator"));
+		assertThat(TestUtils.getPropertyValue(headers, "idGenerator")).isNull();
 	}
 
 	@Test
@@ -118,8 +115,8 @@ public class IdGeneratorConfigurerTests {
 		context.registerBeanDefinition("foo", new RootBeanDefinition(MyIdGenerator.class));
 		context.refresh();
 		MessageHeaders headers = new MessageHeaders(null);
-		assertEquals(1, headers.getId().getMostSignificantBits());
-		assertEquals(2, headers.getId().getLeastSignificantBits());
+		assertThat(headers.getId().getMostSignificantBits()).isEqualTo(1);
+		assertThat(headers.getId().getLeastSignificantBits()).isEqualTo(2);
 
 		GenericApplicationContext context2 = new GenericApplicationContext();
 		context2.registerBeanDefinition("bfpp", new RootBeanDefinition(DefaultConfiguringBeanFactoryPostProcessor.class));
@@ -129,16 +126,16 @@ public class IdGeneratorConfigurerTests {
 		context.close();
 		// we should still use the custom strategy
 		headers = new MessageHeaders(null);
-		assertEquals(1, headers.getId().getMostSignificantBits());
-		assertEquals(2, headers.getId().getLeastSignificantBits());
+		assertThat(headers.getId().getMostSignificantBits()).isEqualTo(1);
+		assertThat(headers.getId().getLeastSignificantBits()).isEqualTo(2);
 
 		context2.close();
 		// back to default
 		headers = new MessageHeaders(null);
-		assertNotEquals(1, headers.getId().getMostSignificantBits());
-		assertNotEquals(2, headers.getId().getLeastSignificantBits());
+		assertThat(headers.getId().getMostSignificantBits()).isNotEqualTo(1);
+		assertThat(headers.getId().getLeastSignificantBits()).isNotEqualTo(2);
 
-		assertNull(TestUtils.getPropertyValue(headers, "idGenerator"));
+		assertThat(TestUtils.getPropertyValue(headers, "idGenerator")).isNull();
 	}
 
 	@Test
@@ -148,8 +145,8 @@ public class IdGeneratorConfigurerTests {
 		context.registerBeanDefinition("foo", new RootBeanDefinition(MyIdGenerator.class));
 		context.refresh();
 		MessageHeaders headers = new MessageHeaders(null);
-		assertEquals(1, headers.getId().getMostSignificantBits());
-		assertEquals(2, headers.getId().getLeastSignificantBits());
+		assertThat(headers.getId().getMostSignificantBits()).isEqualTo(1);
+		assertThat(headers.getId().getLeastSignificantBits()).isEqualTo(2);
 
 		GenericApplicationContext context2 = new GenericApplicationContext();
 		context2.registerBeanDefinition("bfpp", new RootBeanDefinition(DefaultConfiguringBeanFactoryPostProcessor.class));
@@ -159,8 +156,8 @@ public class IdGeneratorConfigurerTests {
 			fail("Expected exception");
 		}
 		catch (BeanDefinitionStoreException e) {
-			assertEquals("'MessageHeaders.idGenerator' has already been set and can not be set again",
-					e.getMessage());
+			assertThat(e.getMessage())
+					.isEqualTo("'MessageHeaders.idGenerator' has already been set and can not be set again");
 		}
 
 		context.close();
@@ -174,7 +171,7 @@ public class IdGeneratorConfigurerTests {
 		context.registerBeanDefinition("foo", new RootBeanDefinition(JdkIdGenerator.class));
 		context.refresh();
 		MessageHeaders headers = new MessageHeaders(null);
-		assertSame(context.getBean(IdGenerator.class), TestUtils.getPropertyValue(headers, "idGenerator"));
+		assertThat(TestUtils.getPropertyValue(headers, "idGenerator")).isSameAs(context.getBean(IdGenerator.class));
 
 		context.close();
 	}
@@ -187,19 +184,19 @@ public class IdGeneratorConfigurerTests {
 		context.refresh();
 		IdGenerator idGenerator = context.getBean(IdGenerator.class);
 		MessageHeaders headers = new MessageHeaders(null);
-		assertEquals(0, headers.getId().getMostSignificantBits());
-		assertEquals(1, headers.getId().getLeastSignificantBits());
+		assertThat(headers.getId().getMostSignificantBits()).isEqualTo(0);
+		assertThat(headers.getId().getLeastSignificantBits()).isEqualTo(1);
 		headers = new MessageHeaders(null);
-		assertEquals(0, headers.getId().getMostSignificantBits());
-		assertEquals(2, headers.getId().getLeastSignificantBits());
+		assertThat(headers.getId().getMostSignificantBits()).isEqualTo(0);
+		assertThat(headers.getId().getLeastSignificantBits()).isEqualTo(2);
 		AtomicLong bottomBits = TestUtils.getPropertyValue(idGenerator, "bottomBits", AtomicLong.class);
 		bottomBits.set(0xffffffff);
 		headers = new MessageHeaders(null);
-		assertEquals(1, headers.getId().getMostSignificantBits());
-		assertEquals(0, headers.getId().getLeastSignificantBits());
+		assertThat(headers.getId().getMostSignificantBits()).isEqualTo(1);
+		assertThat(headers.getId().getLeastSignificantBits()).isEqualTo(0);
 		headers = new MessageHeaders(null);
-		assertEquals(1, headers.getId().getMostSignificantBits());
-		assertEquals(1, headers.getId().getLeastSignificantBits());
+		assertThat(headers.getId().getMostSignificantBits()).isEqualTo(1);
+		assertThat(headers.getId().getLeastSignificantBits()).isEqualTo(1);
 
 		context.close();
 	}

spring-integration-core/src/test/java/org/springframework/integration/config/InvalidPriorityChannelParserTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2016 the original author or authors.
+ * Copyright 2002-2019 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -16,10 +16,9 @@
 
 package org.springframework.integration.config;
 
-import org.hamcrest.Matchers;
-import org.junit.Rule;
+import static org.assertj.core.api.Assertions.assertThatThrownBy;
+
 import org.junit.Test;
-import org.junit.rules.ExpectedException;
 
 import org.springframework.beans.factory.parsing.BeanDefinitionParsingException;
 import org.springframework.context.support.ClassPathXmlApplicationContext;
@@ -27,27 +26,29 @@ import org.springframework.context.support.ClassPathXmlApplicationContext;
 /**
  * @author Dave Syer
  * @author Manuel Jordan
+ * @author Artem Bilan
+ *
  * @since 4.3
  */
 public class InvalidPriorityChannelParserTests {
 
-	@Rule
-	public ExpectedException exception = ExpectedException.none();
-
 	@Test
-	public void testMessageStoreAndCapacityIllegal() throws Exception {
-		this.exception.expect(BeanDefinitionParsingException.class);
-		this.exception.expectMessage(Matchers.containsString("'capacity' attribute is not allowed"));
-		new ClassPathXmlApplicationContext("InvalidPriorityChannelWithMessageStoreAndCapacityParserTests.xml",
-				getClass()).close();
+	public void testMessageStoreAndCapacityIllegal() {
+		assertThatThrownBy(() ->
+				new ClassPathXmlApplicationContext("InvalidPriorityChannelWithMessageStoreAndCapacityParserTests.xml",
+						getClass()))
+				.isInstanceOf(BeanDefinitionParsingException.class)
+				.hasMessageContaining("'capacity' attribute is not allowed");
 	}
 
 	@Test
-	public void testComparatorAndMessageStoreIllegal() throws Exception {
-		this.exception.expect(BeanDefinitionParsingException.class);
-		this.exception.expectMessage(Matchers.containsString("The 'message-store' attribute is not allowed"));
-		new ClassPathXmlApplicationContext("InvalidPriorityChannelWithComparatorAndMessageStoreParserTests.xml",
-				getClass()).close();
+	public void testComparatorAndMessageStoreIllegal() {
+		assertThatThrownBy(() ->
+				new ClassPathXmlApplicationContext(
+						"InvalidPriorityChannelWithComparatorAndMessageStoreParserTests.xml",
+						getClass()))
+				.isInstanceOf(BeanDefinitionParsingException.class)
+				.hasMessageContaining("The 'message-store' attribute is not allowed");
 	}
 
 }

spring-integration-core/src/test/java/org/springframework/integration/config/InvalidQueueChannelParserTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2016 the original author or authors.
+ * Copyright 2002-2019 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -16,10 +16,9 @@
 
 package org.springframework.integration.config;
 
-import org.hamcrest.Matchers;
-import org.junit.Rule;
+import static org.assertj.core.api.Assertions.assertThatThrownBy;
+
 import org.junit.Test;
-import org.junit.rules.ExpectedException;
 
 import org.springframework.beans.factory.parsing.BeanDefinitionParsingException;
 import org.springframework.context.support.ClassPathXmlApplicationContext;
@@ -31,31 +30,32 @@ import org.springframework.context.support.ClassPathXmlApplicationContext;
  */
 public class InvalidQueueChannelParserTests {
 
-	@Rule
-	public ExpectedException exception = ExpectedException.none();
-
 	@Test
-	public void testMessageStoreAndCapacityIllegal() throws Exception {
-		this.exception.expect(BeanDefinitionParsingException.class);
-		this.exception.expectMessage(Matchers.containsString("'capacity' attribute is not allowed"));
-		new ClassPathXmlApplicationContext("InvalidQueueChannelWithMessageStoreAndCapacityParserTests.xml",
-				getClass()).close();
+	public void testMessageStoreAndCapacityIllegal() {
+		assertThatThrownBy(() ->
+				new ClassPathXmlApplicationContext("InvalidQueueChannelWithMessageStoreAndCapacityParserTests.xml",
+						getClass()))
+				.isInstanceOf(BeanDefinitionParsingException.class)
+				.hasMessageContaining("'capacity' attribute is not allowed");
 	}
 
 	@Test
-	public void testRefAndCapacityIllegal() throws Exception {
-		this.exception.expect(BeanDefinitionParsingException.class);
-		this.exception.expectMessage(Matchers.containsString("'capacity' attribute is not allowed"));
-		new ClassPathXmlApplicationContext("InvalidQueueChannelWithRefAndCapacityParserTests.xml", getClass())
-				.close();
+	public void testRefAndCapacityIllegal() {
+		assertThatThrownBy(() ->
+				new ClassPathXmlApplicationContext("InvalidQueueChannelWithRefAndCapacityParserTests.xml",
+						getClass()))
+				.isInstanceOf(BeanDefinitionParsingException.class)
+				.hasMessageContaining("'capacity' attribute is not allowed");
 	}
 
 	@Test
-	public void testRefAndMessageStoreIllegal() throws Exception {
-		this.exception.expect(BeanDefinitionParsingException.class);
-		this.exception.expectMessage(Matchers.containsString("'message-store' attribute is not allowed"));
-		new ClassPathXmlApplicationContext("InvalidQueueChannelWithRefAndMessageStoreParserTests.xml", getClass())
-				.close();
+	public void testRefAndMessageStoreIllegal() {
+		assertThatThrownBy(() ->
+				new ClassPathXmlApplicationContext("InvalidQueueChannelWithRefAndMessageStoreParserTests.xml",
+						getClass()))
+				.isInstanceOf(BeanDefinitionParsingException.class)
+				.hasMessageContaining("The 'message-store' attribute is not allowed " +
+						"when providing a 'ref' to a custom queue.");
 	}
 
 }

spring-integration-core/src/test/java/org/springframework/integration/config/MessageBusParserTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2015 the original author or authors.
+ * Copyright 2002-2019 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -16,8 +16,7 @@
 
 package org.springframework.integration.config;
 
-import static org.junit.Assert.assertEquals;
-import static org.junit.Assert.assertNull;
+import static org.assertj.core.api.Assertions.assertThat;
 
 import org.junit.Test;
 
@@ -45,7 +44,7 @@ public class MessageBusParserTests {
 		ConfigurableApplicationContext context = new ClassPathXmlApplicationContext(
 				"messageBusWithErrorChannel.xml", this.getClass());
 		BeanFactoryChannelResolver resolver = new BeanFactoryChannelResolver(context);
-		assertEquals(context.getBean("errorChannel"), resolver.resolveDestination("errorChannel"));
+		assertThat(resolver.resolveDestination("errorChannel")).isEqualTo(context.getBean("errorChannel"));
 		context.close();
 	}
 
@@ -54,7 +53,7 @@ public class MessageBusParserTests {
 		ConfigurableApplicationContext context = new ClassPathXmlApplicationContext(
 				"messageBusWithDefaults.xml", this.getClass());
 		BeanFactoryChannelResolver resolver = new BeanFactoryChannelResolver(context);
-		assertEquals(context.getBean("errorChannel"), resolver.resolveDestination("errorChannel"));
+		assertThat(resolver.resolveDestination("errorChannel")).isEqualTo(context.getBean("errorChannel"));
 		context.close();
 	}
 
@@ -67,10 +66,10 @@ public class MessageBusParserTests {
 		DirectFieldAccessor accessor = new DirectFieldAccessor(multicaster);
 		Object taskExecutor = accessor.getPropertyValue("taskExecutor");
 		if (SpringVersion.getVersion().startsWith("2")) {
-			assertEquals(SyncTaskExecutor.class, taskExecutor.getClass());
+			assertThat(taskExecutor.getClass()).isEqualTo(SyncTaskExecutor.class);
 		}
 		else {
-			assertNull(taskExecutor);
+			assertThat(taskExecutor).isNull();
 		}
 		context.close();
 	}
@@ -85,10 +84,10 @@ public class MessageBusParserTests {
 		DirectFieldAccessor accessor = new DirectFieldAccessor(multicaster);
 		Object taskExecutor = accessor.getPropertyValue("taskExecutor");
 		if (SpringVersion.getVersion().startsWith("2")) {
-			assertEquals(SyncTaskExecutor.class, taskExecutor.getClass());
+			assertThat(taskExecutor.getClass()).isEqualTo(SyncTaskExecutor.class);
 		}
 		else {
-			assertNull(taskExecutor);
+			assertThat(taskExecutor).isNull();
 		}
 		context.close();
 	}
@@ -102,7 +101,7 @@ public class MessageBusParserTests {
 				context.getBean(AbstractApplicationContext.APPLICATION_EVENT_MULTICASTER_BEAN_NAME);
 		DirectFieldAccessor accessor = new DirectFieldAccessor(multicaster);
 		Object taskExecutor = accessor.getPropertyValue("taskExecutor");
-		assertEquals(ThreadPoolTaskExecutor.class, taskExecutor.getClass());
+		assertThat(taskExecutor.getClass()).isEqualTo(ThreadPoolTaskExecutor.class);
 		context.close();
 	}
 
@@ -111,7 +110,7 @@ public class MessageBusParserTests {
 		AbstractApplicationContext context = new ClassPathXmlApplicationContext(
 				"messageBusWithTaskScheduler.xml", this.getClass());
 		TaskScheduler scheduler = (TaskScheduler) context.getBean("taskScheduler");
-		assertEquals(StubTaskScheduler.class, scheduler.getClass());
+		assertThat(scheduler.getClass()).isEqualTo(StubTaskScheduler.class);
 		context.close();
 	}
 
@@ -120,7 +119,7 @@ public class MessageBusParserTests {
 		AbstractApplicationContext context = new ClassPathXmlApplicationContext(
 				"messageBusWithTaskScheduler.xml", this.getClass());
 		TaskScheduler scheduler = (TaskScheduler) context.getBean("taskScheduler");
-		assertEquals(scheduler, IntegrationContextUtils.getTaskScheduler(context));
+		assertThat(IntegrationContextUtils.getTaskScheduler(context)).isEqualTo(scheduler);
 		context.close();
 	}
 

spring-integration-core/src/test/java/org/springframework/integration/config/PublishSubscribeChannelParserTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2018 the original author or authors.
+ * Copyright 2002-2019 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -16,12 +16,7 @@
 
 package org.springframework.integration.config;
 
-import static org.junit.Assert.assertEquals;
-import static org.junit.Assert.assertFalse;
-import static org.junit.Assert.assertNotNull;
-import static org.junit.Assert.assertNull;
-import static org.junit.Assert.assertSame;
-import static org.junit.Assert.assertTrue;
+import static org.assertj.core.api.Assertions.assertThat;
 
 import java.util.concurrent.Executor;
 
@@ -60,11 +55,11 @@ public class PublishSubscribeChannelParserTests {
 		dispatcher.addHandler(message -> { });
 		dispatcher.dispatch(new GenericMessage<>("foo"));
 		DirectFieldAccessor dispatcherAccessor = new DirectFieldAccessor(dispatcher);
-		assertNull(dispatcherAccessor.getPropertyValue("executor"));
-		assertFalse((Boolean) dispatcherAccessor.getPropertyValue("ignoreFailures"));
-		assertTrue((Boolean) dispatcherAccessor.getPropertyValue("applySequence"));
+		assertThat(dispatcherAccessor.getPropertyValue("executor")).isNull();
+		assertThat((Boolean) dispatcherAccessor.getPropertyValue("ignoreFailures")).isFalse();
+		assertThat((Boolean) dispatcherAccessor.getPropertyValue("applySequence")).isTrue();
 		Object mbf = this.context.getBean(IntegrationUtils.INTEGRATION_MESSAGE_BUILDER_FACTORY_BEAN_NAME);
-		assertSame(mbf, dispatcherAccessor.getPropertyValue("messageBuilderFactory"));
+		assertThat(dispatcherAccessor.getPropertyValue("messageBuilderFactory")).isSameAs(mbf);
 	}
 
 	@Test
@@ -74,7 +69,7 @@ public class PublishSubscribeChannelParserTests {
 		DirectFieldAccessor accessor = new DirectFieldAccessor(channel);
 		BroadcastingDispatcher dispatcher = (BroadcastingDispatcher)
 				accessor.getPropertyValue("dispatcher");
-		assertTrue((Boolean) new DirectFieldAccessor(dispatcher).getPropertyValue("ignoreFailures"));
+		assertThat((Boolean) new DirectFieldAccessor(dispatcher).getPropertyValue("ignoreFailures")).isTrue();
 	}
 
 	@Test
@@ -84,7 +79,7 @@ public class PublishSubscribeChannelParserTests {
 		DirectFieldAccessor accessor = new DirectFieldAccessor(channel);
 		BroadcastingDispatcher dispatcher = (BroadcastingDispatcher)
 				accessor.getPropertyValue("dispatcher");
-		assertTrue((Boolean) new DirectFieldAccessor(dispatcher).getPropertyValue("applySequence"));
+		assertThat((Boolean) new DirectFieldAccessor(dispatcher).getPropertyValue("applySequence")).isTrue();
 	}
 
 	@Test
@@ -96,11 +91,11 @@ public class PublishSubscribeChannelParserTests {
 				accessor.getPropertyValue("dispatcher");
 		DirectFieldAccessor dispatcherAccessor = new DirectFieldAccessor(dispatcher);
 		Executor executor = (Executor) dispatcherAccessor.getPropertyValue("executor");
-		assertNotNull(executor);
-		assertEquals(ErrorHandlingTaskExecutor.class, executor.getClass());
+		assertThat(executor).isNotNull();
+		assertThat(executor.getClass()).isEqualTo(ErrorHandlingTaskExecutor.class);
 		DirectFieldAccessor executorAccessor = new DirectFieldAccessor(executor);
 		Executor innerExecutor = (Executor) executorAccessor.getPropertyValue("executor");
-		assertEquals(context.getBean("pool"), innerExecutor);
+		assertThat(innerExecutor).isEqualTo(context.getBean("pool"));
 	}
 
 	@Test
@@ -111,13 +106,13 @@ public class PublishSubscribeChannelParserTests {
 		BroadcastingDispatcher dispatcher = (BroadcastingDispatcher)
 				accessor.getPropertyValue("dispatcher");
 		DirectFieldAccessor dispatcherAccessor = new DirectFieldAccessor(dispatcher);
-		assertTrue((Boolean) dispatcherAccessor.getPropertyValue("ignoreFailures"));
+		assertThat((Boolean) dispatcherAccessor.getPropertyValue("ignoreFailures")).isTrue();
 		Executor executor = (Executor) dispatcherAccessor.getPropertyValue("executor");
-		assertNotNull(executor);
-		assertEquals(ErrorHandlingTaskExecutor.class, executor.getClass());
+		assertThat(executor).isNotNull();
+		assertThat(executor.getClass()).isEqualTo(ErrorHandlingTaskExecutor.class);
 		DirectFieldAccessor executorAccessor = new DirectFieldAccessor(executor);
 		Executor innerExecutor = (Executor) executorAccessor.getPropertyValue("executor");
-		assertEquals(this.context.getBean("pool"), innerExecutor);
+		assertThat(innerExecutor).isEqualTo(this.context.getBean("pool"));
 	}
 
 	@Test
@@ -128,13 +123,13 @@ public class PublishSubscribeChannelParserTests {
 		BroadcastingDispatcher dispatcher = (BroadcastingDispatcher)
 				accessor.getPropertyValue("dispatcher");
 		DirectFieldAccessor dispatcherAccessor = new DirectFieldAccessor(dispatcher);
-		assertTrue((Boolean) dispatcherAccessor.getPropertyValue("applySequence"));
+		assertThat((Boolean) dispatcherAccessor.getPropertyValue("applySequence")).isTrue();
 		Executor executor = (Executor) dispatcherAccessor.getPropertyValue("executor");
-		assertNotNull(executor);
-		assertEquals(ErrorHandlingTaskExecutor.class, executor.getClass());
+		assertThat(executor).isNotNull();
+		assertThat(executor.getClass()).isEqualTo(ErrorHandlingTaskExecutor.class);
 		DirectFieldAccessor executorAccessor = new DirectFieldAccessor(executor);
 		Executor innerExecutor = (Executor) executorAccessor.getPropertyValue("executor");
-		assertEquals(this.context.getBean("pool"), innerExecutor);
+		assertThat(innerExecutor).isEqualTo(this.context.getBean("pool"));
 	}
 
 	@Test
@@ -143,8 +138,8 @@ public class PublishSubscribeChannelParserTests {
 				this.context.getBean("channelWithErrorHandler", PublishSubscribeChannel.class);
 		DirectFieldAccessor accessor = new DirectFieldAccessor(channel);
 		ErrorHandler errorHandler = (ErrorHandler) accessor.getPropertyValue("errorHandler");
-		assertNotNull(errorHandler);
-		assertEquals(this.context.getBean("testErrorHandler"), errorHandler);
+		assertThat(errorHandler).isNotNull();
+		assertThat(errorHandler).isEqualTo(this.context.getBean("testErrorHandler"));
 	}
 
 }

spring-integration-core/src/test/java/org/springframework/integration/config/ReleaseStrategyFactoryBeanTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2014-2018 the original author or authors.
+ * Copyright 2014-2019 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -16,12 +16,8 @@
 
 package org.springframework.integration.config;
 
-import static org.hamcrest.Matchers.containsString;
-import static org.hamcrest.Matchers.equalTo;
-import static org.hamcrest.Matchers.instanceOf;
-import static org.hamcrest.Matchers.is;
-import static org.junit.Assert.assertThat;
-import static org.junit.Assert.fail;
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.assertj.core.api.Assertions.fail;
 
 import java.util.Collection;
 
@@ -52,10 +48,10 @@ public class ReleaseStrategyFactoryBeanTests {
 			fail("IllegalStateException expected");
 		}
 		catch (Exception e) {
-			assertThat(e, instanceOf(IllegalStateException.class));
-			assertThat(e.getMessage(), containsString("Target object of type " +
+			assertThat(e).isInstanceOf(IllegalStateException.class);
+			assertThat(e.getMessage()).contains("Target object of type " +
 					"[class org.springframework.integration.config.ReleaseStrategyFactoryBeanTests$Foo] " +
-					"has no eligible methods for handling Messages."));
+					"has no eligible methods for handling Messages.");
 		}
 	}
 
@@ -67,10 +63,10 @@ public class ReleaseStrategyFactoryBeanTests {
 		factory.setMethodName("doRelease2");
 		factory.afterPropertiesSet();
 		ReleaseStrategy delegate = factory.getObject();
-		assertThat(delegate, instanceOf(MethodInvokingReleaseStrategy.class));
-		assertThat(TestUtils.getPropertyValue(delegate, "adapter.delegate.targetObject", Bar.class), is(bar));
-		assertThat(TestUtils.getPropertyValue(delegate, "adapter.delegate.handlerMethod.expressionString"),
-				equalTo("#target.doRelease2(messages)"));
+		assertThat(delegate).isInstanceOf(MethodInvokingReleaseStrategy.class);
+		assertThat(TestUtils.getPropertyValue(delegate, "adapter.delegate.targetObject", Bar.class)).isEqualTo(bar);
+		assertThat(TestUtils.getPropertyValue(delegate, "adapter.delegate.handlerMethod.expressionString"))
+				.isEqualTo("#target.doRelease2(messages)");
 	}
 
 	@Test
@@ -80,8 +76,8 @@ public class ReleaseStrategyFactoryBeanTests {
 		factory.setTarget(bar);
 		factory.afterPropertiesSet();
 		ReleaseStrategy delegate = factory.getObject();
-		assertThat(delegate, instanceOf(MethodInvokingReleaseStrategy.class));
-		assertThat(TestUtils.getPropertyValue(delegate, "adapter.delegate.targetObject", Bar.class), is(bar));
+		assertThat(delegate).isInstanceOf(MethodInvokingReleaseStrategy.class);
+		assertThat(TestUtils.getPropertyValue(delegate, "adapter.delegate.targetObject", Bar.class)).isEqualTo(bar);
 	}
 
 	@Test
@@ -89,7 +85,7 @@ public class ReleaseStrategyFactoryBeanTests {
 		ReleaseStrategyFactoryBean factory = new ReleaseStrategyFactoryBean();
 		factory.afterPropertiesSet();
 		ReleaseStrategy delegate = factory.getObject();
-		assertThat(delegate, instanceOf(SimpleSequenceSizeReleaseStrategy.class));
+		assertThat(delegate).isInstanceOf(SimpleSequenceSizeReleaseStrategy.class);
 	}
 
 	@Test
@@ -99,7 +95,7 @@ public class ReleaseStrategyFactoryBeanTests {
 		factory.setTarget(foo);
 		factory.afterPropertiesSet();
 		ReleaseStrategy delegate = factory.getObject();
-		assertThat(delegate, instanceOf(SimpleSequenceSizeReleaseStrategy.class));
+		assertThat(delegate).isInstanceOf(SimpleSequenceSizeReleaseStrategy.class);
 	}
 
 	@Test
@@ -109,7 +105,7 @@ public class ReleaseStrategyFactoryBeanTests {
 		factory.setTarget(baz);
 		factory.afterPropertiesSet();
 		ReleaseStrategy delegate = factory.getObject();
-		assertThat(delegate, is(baz));
+		assertThat(delegate).isEqualTo(baz);
 	}
 
 	@Test
@@ -120,10 +116,10 @@ public class ReleaseStrategyFactoryBeanTests {
 		factory.setMethodName("doRelease2");
 		factory.afterPropertiesSet();
 		ReleaseStrategy delegate = factory.getObject();
-		assertThat(delegate, instanceOf(MethodInvokingReleaseStrategy.class));
-		assertThat(TestUtils.getPropertyValue(delegate, "adapter.delegate.targetObject", Baz.class), is(baz));
-		assertThat(TestUtils.getPropertyValue(delegate, "adapter.delegate.handlerMethod.expressionString"),
-				equalTo("#target.doRelease2(messages)"));
+		assertThat(delegate).isInstanceOf(MethodInvokingReleaseStrategy.class);
+		assertThat(TestUtils.getPropertyValue(delegate, "adapter.delegate.targetObject", Baz.class)).isEqualTo(baz);
+		assertThat(TestUtils.getPropertyValue(delegate, "adapter.delegate.handlerMethod.expressionString"))
+				.isEqualTo("#target.doRelease2(messages)");
 	}
 
 	public class Foo {

spring-integration-core/src/test/java/org/springframework/integration/config/ResequencerParserTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2018 the original author or authors.
+ * Copyright 2002-2019 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -16,10 +16,7 @@
 
 package org.springframework.integration.config;
 
-import static org.junit.Assert.assertEquals;
-import static org.junit.Assert.assertFalse;
-import static org.junit.Assert.assertNull;
-import static org.junit.Assert.assertTrue;
+import static org.assertj.core.api.Assertions.assertThat;
 import static org.springframework.integration.test.util.TestUtils.getPropertyValue;
 
 import java.util.List;
@@ -66,15 +63,18 @@ public class ResequencerParserTests {
 		EventDrivenConsumer endpoint = (EventDrivenConsumer) context.getBean("defaultResequencer");
 		ResequencingMessageHandler resequencer = TestUtils.getPropertyValue(endpoint, "handler",
 				ResequencingMessageHandler.class);
-		assertNull(getPropertyValue(resequencer, "outputChannel"));
-		assertTrue(getPropertyValue(resequencer, "discardChannel") instanceof NullChannel);
-		assertEquals("The ResequencerEndpoint is not set with the appropriate timeout value", -1L, getPropertyValue(
-				resequencer, "messagingTemplate.sendTimeout"));
-		assertEquals(
-				"The ResequencerEndpoint is not configured with the appropriate 'send partial results on timeout' flag",
-				false, getPropertyValue(resequencer, "sendPartialResultOnExpiry"));
-		assertEquals("The ResequencerEndpoint is not configured with the appropriate 'release partial sequences' flag",
-				false, getPropertyValue(resequencer, "releasePartialSequences"));
+		assertThat(getPropertyValue(resequencer, "outputChannel")).isNull();
+		assertThat(getPropertyValue(resequencer, "discardChannel") instanceof NullChannel).isTrue();
+		assertThat(getPropertyValue(
+				resequencer, "messagingTemplate.sendTimeout"))
+				.as("The ResequencerEndpoint is not set with the appropriate timeout value").isEqualTo(-1L);
+		assertThat(getPropertyValue(resequencer, "sendPartialResultOnExpiry"))
+				.as("The ResequencerEndpoint is not configured with the appropriate 'send partial results on timeout' " +
+						"flag")
+				.isEqualTo(false);
+		assertThat(getPropertyValue(resequencer, "releasePartialSequences"))
+				.as("The ResequencerEndpoint is not configured with the appropriate 'release partial sequences' flag")
+				.isEqualTo(false);
 	}
 
 	@Test
@@ -84,18 +84,23 @@ public class ResequencerParserTests {
 		MessageChannel discardChannel = (MessageChannel) context.getBean("discardChannel");
 		ResequencingMessageHandler resequencer = TestUtils.getPropertyValue(endpoint, "handler",
 				ResequencingMessageHandler.class);
-		assertEquals("The ResequencerEndpoint is not injected with the appropriate output channel", outputChannel,
-				getPropertyValue(resequencer, "outputChannel"));
-		assertEquals("The ResequencerEndpoint is not injected with the appropriate discard channel", discardChannel,
-				getPropertyValue(resequencer, "discardChannel"));
-		assertEquals("The ResequencerEndpoint is not set with the appropriate timeout value", 86420000L,
-				getPropertyValue(resequencer, "messagingTemplate.sendTimeout"));
-		assertEquals(
-				"The ResequencerEndpoint is not configured with the appropriate 'send partial results on timeout' flag",
-				true, getPropertyValue(resequencer, "sendPartialResultOnExpiry"));
-		assertEquals("The ResequencerEndpoint is not configured with the appropriate 'release partial sequences' flag",
-				true, getPropertyValue(getPropertyValue(resequencer, "releaseStrategy"), "releasePartialSequences"));
-		assertEquals(60000L, getPropertyValue(resequencer, "minimumTimeoutForEmptyGroups", Long.class).longValue());
+		assertThat(getPropertyValue(resequencer, "outputChannel"))
+				.as("The ResequencerEndpoint is not injected with the appropriate output channel")
+				.isEqualTo(outputChannel);
+		assertThat(getPropertyValue(resequencer, "discardChannel"))
+				.as("The ResequencerEndpoint is not injected with the appropriate discard channel")
+				.isEqualTo(discardChannel);
+		assertThat(getPropertyValue(resequencer, "messagingTemplate.sendTimeout"))
+				.as("The ResequencerEndpoint is not set with the appropriate timeout value").isEqualTo(86420000L);
+		assertThat(getPropertyValue(resequencer, "sendPartialResultOnExpiry"))
+				.as("The ResequencerEndpoint is not configured with the appropriate 'send partial results on timeout' " +
+						"flag")
+				.isEqualTo(true);
+		assertThat(getPropertyValue(getPropertyValue(resequencer, "releaseStrategy"), "releasePartialSequences"))
+				.as("The ResequencerEndpoint is not configured with the appropriate 'release partial sequences' flag")
+				.isEqualTo(true);
+		assertThat(getPropertyValue(resequencer, "minimumTimeoutForEmptyGroups", Long.class).longValue())
+				.isEqualTo(60000L);
 	}
 
 	@Test
@@ -104,38 +109,44 @@ public class ResequencerParserTests {
 				.getBean("resequencerWithCorrelationStrategyRefOnly");
 		ResequencingMessageHandler resequencer = TestUtils.getPropertyValue(endpoint, "handler",
 				ResequencingMessageHandler.class);
-		assertEquals("The ResequencerEndpoint is not configured with the appropriate CorrelationStrategy", context
-				.getBean("testCorrelationStrategy"), getPropertyValue(resequencer, "correlationStrategy"));
+		assertThat(getPropertyValue(resequencer, "correlationStrategy"))
+				.as("The ResequencerEndpoint is not configured with the appropriate CorrelationStrategy")
+				.isEqualTo(context
+						.getBean("testCorrelationStrategy"));
 	}
 
 	@Test
 	public void testReleaseStrategyRefOnly() throws Exception {
 		EventDrivenConsumer endpoint = (EventDrivenConsumer) context.getBean("resequencerWithReleaseStrategyRefOnly");
-		ResequencingMessageHandler resequencer = getPropertyValue(endpoint, "handler", ResequencingMessageHandler.class);
-		assertEquals("The ResequencerEndpoint is not configured with the appropriate ReleaseStrategy",
-				context.getBean("testReleaseStrategy"), getPropertyValue(resequencer, "releaseStrategy"));
-		assertFalse(TestUtils.getPropertyValue(resequencer, "expireGroupsUponTimeout", Boolean.class));
+		ResequencingMessageHandler resequencer = getPropertyValue(endpoint, "handler",
+				ResequencingMessageHandler.class);
+		assertThat(getPropertyValue(resequencer, "releaseStrategy"))
+				.as("The ResequencerEndpoint is not configured with the appropriate ReleaseStrategy")
+				.isEqualTo(context.getBean("testReleaseStrategy"));
+		assertThat(TestUtils.getPropertyValue(resequencer, "expireGroupsUponTimeout", Boolean.class)).isFalse();
 	}
 
 	@Test
 	public void testReleaseStrategyRefAndMethod() throws Exception {
 		EventDrivenConsumer endpoint = (EventDrivenConsumer) context
 				.getBean("resequencerWithReleaseStrategyRefAndMethod");
-		ResequencingMessageHandler resequencer = getPropertyValue(endpoint, "handler", ResequencingMessageHandler.class);
+		ResequencingMessageHandler resequencer = getPropertyValue(endpoint, "handler",
+				ResequencingMessageHandler.class);
 
 		Object releaseStrategyBean = context.getBean("testReleaseStrategyPojo");
-		assertTrue("Release strategy is not of the expected type",
-				releaseStrategyBean instanceof TestReleaseStrategyPojo);
+		assertThat(releaseStrategyBean instanceof TestReleaseStrategyPojo)
+				.as("Release strategy is not of the expected type").isTrue();
 		TestReleaseStrategyPojo expectedReleaseStrategy = (TestReleaseStrategyPojo) releaseStrategyBean;
 
 		int currentInvocationCount = expectedReleaseStrategy.invocationCount;
 		ReleaseStrategy effectiveReleaseStrategy = (ReleaseStrategy) getPropertyValue(resequencer, "releaseStrategy");
-		assertTrue("The release strategy is expected to be a MethodInvokingReleaseStrategy",
-				effectiveReleaseStrategy instanceof MethodInvokingReleaseStrategy);
+		assertThat(effectiveReleaseStrategy instanceof MethodInvokingReleaseStrategy)
+				.as("The release strategy is expected to be a MethodInvokingReleaseStrategy").isTrue();
 		effectiveReleaseStrategy.canRelease(new SimpleMessageGroup("test"));
-		assertEquals("The ResequencerEndpoint was not invoked the expected number of times;",
-				currentInvocationCount + 1, expectedReleaseStrategy.invocationCount);
-		assertTrue(TestUtils.getPropertyValue(resequencer, "expireGroupsUponTimeout", Boolean.class));
+		assertThat(expectedReleaseStrategy.invocationCount)
+				.as("The ResequencerEndpoint was not invoked the expected number of times;")
+				.isEqualTo(currentInvocationCount + 1);
+		assertThat(TestUtils.getPropertyValue(resequencer, "expireGroupsUponTimeout", Boolean.class)).isTrue();
 	}
 
 	@Test
@@ -143,8 +154,9 @@ public class ResequencerParserTests {
 				EventDrivenConsumer endpoint = (EventDrivenConsumer) context.getBean("completelyDefinedResequencer");
 				ResequencingMessageHandler resequencer = TestUtils.getPropertyValue(endpoint, "handler",
 						ResequencingMessageHandler.class);
-		assertEquals("The ResequencerEndpoint is not configured with the appropriate 'release partial sequences' flag",
-				true, getPropertyValue(getPropertyValue(resequencer, "releaseStrategy"), "releasePartialSequences"));
+		assertThat(getPropertyValue(getPropertyValue(resequencer, "releaseStrategy"), "releasePartialSequences"))
+				.as("The ResequencerEndpoint is not configured with the appropriate 'release partial sequences' flag")
+				.isEqualTo(true);
 	}
 
 	@Test
@@ -154,10 +166,11 @@ public class ResequencerParserTests {
 		ResequencingMessageHandler resequencer = TestUtils.getPropertyValue(endpoint, "handler",
 				ResequencingMessageHandler.class);
 		Object correlationStrategy = getPropertyValue(resequencer, "correlationStrategy");
-		assertEquals("The ResequencerEndpoint is not configured with a CorrelationStrategy adapter",
-				MethodInvokingCorrelationStrategy.class, correlationStrategy.getClass());
+		assertThat(correlationStrategy.getClass())
+				.as("The ResequencerEndpoint is not configured with a CorrelationStrategy adapter")
+				.isEqualTo(MethodInvokingCorrelationStrategy.class);
 		MethodInvokingCorrelationStrategy adapter = (MethodInvokingCorrelationStrategy) correlationStrategy;
-		assertEquals("foo", adapter.getCorrelationKey(MessageBuilder.withPayload("not important").build()));
+		assertThat(adapter.getCorrelationKey(MessageBuilder.withPayload("not important").build())).isEqualTo("foo");
 	}
 
 	@SuppressWarnings("unused")

spring-integration-core/src/test/java/org/springframework/integration/config/ResequencerWithMessageStoreParserTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2017 the original author or authors.
+ * Copyright 2002-2019 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -16,8 +16,7 @@
 
 package org.springframework.integration.config;
 
-import static org.junit.Assert.assertEquals;
-import static org.junit.Assert.assertNotNull;
+import static org.assertj.core.api.Assertions.assertThat;
 
 import org.junit.Test;
 import org.junit.runner.RunWith;
@@ -56,21 +55,21 @@ public class ResequencerWithMessageStoreParserTests {
 	public void testResequence() {
 
 		input.send(createMessage("123", "id1", 3, 1, null));
-		assertEquals(1, messageGroupStore.getMessageGroup("id1").size());
+		assertThat(messageGroupStore.getMessageGroup("id1").size()).isEqualTo(1);
 		input.send(createMessage("789", "id1", 3, 3, null));
-		assertEquals(2, messageGroupStore.getMessageGroup("id1").size());
+		assertThat(messageGroupStore.getMessageGroup("id1").size()).isEqualTo(2);
 		input.send(createMessage("456", "id1", 3, 2, null));
 
 		Message<?> message1 = output.receive(500);
 		Message<?> message2 = output.receive(500);
 		Message<?> message3 = output.receive(500);
 
-		assertNotNull(message1);
-		assertEquals(1, new IntegrationMessageHeaderAccessor(message1).getSequenceNumber());
-		assertNotNull(message2);
-		assertEquals(2, new IntegrationMessageHeaderAccessor(message2).getSequenceNumber());
-		assertNotNull(message3);
-		assertEquals(3, new IntegrationMessageHeaderAccessor(message3).getSequenceNumber());
+		assertThat(message1).isNotNull();
+		assertThat(new IntegrationMessageHeaderAccessor(message1).getSequenceNumber()).isEqualTo(1);
+		assertThat(message2).isNotNull();
+		assertThat(new IntegrationMessageHeaderAccessor(message2).getSequenceNumber()).isEqualTo(2);
+		assertThat(message3).isNotNull();
+		assertThat(new IntegrationMessageHeaderAccessor(message3).getSequenceNumber()).isEqualTo(3);
 
 	}
 

spring-integration-core/src/test/java/org/springframework/integration/config/RouterFactoryBeanDelegationTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2018 the original author or authors.
+ * Copyright 2002-2019 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -16,9 +16,7 @@
 
 package org.springframework.integration.config;
 
-import static org.junit.Assert.assertNotNull;
-import static org.junit.Assert.assertNull;
-import static org.junit.Assert.assertTrue;
+import static org.assertj.core.api.Assertions.assertThat;
 
 import org.junit.Test;
 import org.junit.runner.RunWith;
@@ -62,21 +60,21 @@ public class RouterFactoryBeanDelegationTests {
 	public void checkResolutionRequiredConfiguredOnTargetRouter() {
 		@SuppressWarnings("unchecked")
 		boolean resolutionRequired = (Boolean) new DirectFieldAccessor(router).getPropertyValue("resolutionRequired");
-		assertTrue("The 'resolutionRequired' property should be 'true'", resolutionRequired);
+		assertThat(resolutionRequired).as("The 'resolutionRequired' property should be 'true'").isTrue();
 	}
 
 	@Test
 	public void routeWithMappedType() {
 		input.send(new GenericMessage<>("test"));
-		assertNull(discard.receive(0));
-		assertNotNull(strings.receive(0));
+		assertThat(discard.receive(0)).isNull();
+		assertThat(strings.receive(0)).isNotNull();
 	}
 
 	@Test
 	public void routeWithUnmappedType() {
 		input.send(new GenericMessage<>(123));
-		assertNull(strings.receive(0));
-		assertNotNull(discard.receive(0));
+		assertThat(strings.receive(0)).isNull();
+		assertThat(discard.receive(0)).isNotNull();
 	}
 
 }

spring-integration-core/src/test/java/org/springframework/integration/config/SelectorChainParserTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2018 the original author or authors.
+ * Copyright 2002-2019 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -16,8 +16,7 @@
 
 package org.springframework.integration.config;
 
-import static org.junit.Assert.assertEquals;
-import static org.junit.Assert.assertTrue;
+import static org.assertj.core.api.Assertions.assertThat;
 
 import java.util.List;
 
@@ -53,11 +52,11 @@ public class SelectorChainParserTests {
 		MessageSelector selector2 = (MessageSelector) context.getBean("selector2");
 		MessageSelectorChain chain = (MessageSelectorChain) context.getBean("selectorChain");
 		List<MessageSelector> selectors = this.getSelectors(chain);
-		assertEquals(VotingStrategy.ALL, this.getStrategy(chain));
-		assertEquals(selector1, selectors.get(0));
-		assertEquals(selector2, selectors.get(1));
-		assertTrue(chain.accept(new GenericMessage<>("test")));
-		assertTrue(this.context.containsBean("pojoSelector"));
+		assertThat(this.getStrategy(chain)).isEqualTo(VotingStrategy.ALL);
+		assertThat(selectors.get(0)).isEqualTo(selector1);
+		assertThat(selectors.get(1)).isEqualTo(selector2);
+		assertThat(chain.accept(new GenericMessage<>("test"))).isTrue();
+		assertThat(this.context.containsBean("pojoSelector")).isTrue();
 	}
 
 	@Test
@@ -69,30 +68,30 @@ public class SelectorChainParserTests {
 		MessageSelector selector5 = (MessageSelector) context.getBean("selector5");
 		MessageSelector selector6 = (MessageSelector) context.getBean("selector6");
 		MessageSelectorChain chain1 = (MessageSelectorChain) context.getBean("nestedSelectorChain");
-		assertEquals(VotingStrategy.MAJORITY, this.getStrategy(chain1));
+		assertThat(this.getStrategy(chain1)).isEqualTo(VotingStrategy.MAJORITY);
 		List<MessageSelector> selectorList1 = this.getSelectors(chain1);
-		assertEquals(selector1, selectorList1.get(0));
-		assertTrue(selectorList1.get(1) instanceof MessageSelectorChain);
+		assertThat(selectorList1.get(0)).isEqualTo(selector1);
+		assertThat(selectorList1.get(1) instanceof MessageSelectorChain).isTrue();
 		MessageSelectorChain chain2 = (MessageSelectorChain) selectorList1.get(1);
-		assertEquals(VotingStrategy.ALL, this.getStrategy(chain2));
+		assertThat(this.getStrategy(chain2)).isEqualTo(VotingStrategy.ALL);
 		List<MessageSelector> selectorList2 = this.getSelectors(chain2);
-		assertEquals(selector2, selectorList2.get(0));
-		assertTrue(selectorList2.get(1) instanceof MessageSelectorChain);
+		assertThat(selectorList2.get(0)).isEqualTo(selector2);
+		assertThat(selectorList2.get(1) instanceof MessageSelectorChain).isTrue();
 		MessageSelectorChain chain3 = (MessageSelectorChain) selectorList2.get(1);
-		assertEquals(VotingStrategy.ANY, this.getStrategy(chain3));
+		assertThat(this.getStrategy(chain3)).isEqualTo(VotingStrategy.ANY);
 		List<MessageSelector> selectorList3 = this.getSelectors(chain3);
-		assertEquals(selector3, selectorList3.get(0));
-		assertEquals(selector4, selectorList3.get(1));
-		assertEquals(selector5, selectorList2.get(2));
-		assertTrue(selectorList1.get(2) instanceof MessageSelectorChain);
+		assertThat(selectorList3.get(0)).isEqualTo(selector3);
+		assertThat(selectorList3.get(1)).isEqualTo(selector4);
+		assertThat(selectorList2.get(2)).isEqualTo(selector5);
+		assertThat(selectorList1.get(2) instanceof MessageSelectorChain).isTrue();
 		MessageSelectorChain chain4 = (MessageSelectorChain) selectorList1.get(2);
-		assertEquals(VotingStrategy.MAJORITY_OR_TIE, this.getStrategy(chain4));
+		assertThat(this.getStrategy(chain4)).isEqualTo(VotingStrategy.MAJORITY_OR_TIE);
 		List<MessageSelector> selectorList4 = this.getSelectors(chain4);
-		assertEquals(selector6, selectorList4.get(0));
-		assertTrue(chain1.accept(new GenericMessage<>("test1")));
-		assertTrue(chain2.accept(new GenericMessage<>("test2")));
-		assertTrue(chain3.accept(new GenericMessage<>("test3")));
-		assertTrue(chain4.accept(new GenericMessage<>("test4")));
+		assertThat(selectorList4.get(0)).isEqualTo(selector6);
+		assertThat(chain1.accept(new GenericMessage<>("test1"))).isTrue();
+		assertThat(chain2.accept(new GenericMessage<>("test2"))).isTrue();
+		assertThat(chain3.accept(new GenericMessage<>("test3"))).isTrue();
+		assertThat(chain4.accept(new GenericMessage<>("test4"))).isTrue();
 	}
 
 

spring-integration-core/src/test/java/org/springframework/integration/config/ServiceActivatorAnnotationPostProcessorTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2018 the original author or authors.
+ * Copyright 2002-2019 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -16,8 +16,7 @@
 
 package org.springframework.integration.config;
 
-import static org.junit.Assert.assertEquals;
-import static org.junit.Assert.assertNull;
+import static org.assertj.core.api.Assertions.assertThat;
 
 import java.util.concurrent.CountDownLatch;
 import java.util.concurrent.TimeUnit;
@@ -53,13 +52,13 @@ public class ServiceActivatorAnnotationPostProcessorTests {
 		context.refresh();
 		SimpleServiceActivatorAnnotationTestBean testBean =
 				context.getBean("testBean", SimpleServiceActivatorAnnotationTestBean.class);
-		assertEquals(1, latch.getCount());
-		assertNull(testBean.getMessageText());
+		assertThat(latch.getCount()).isEqualTo(1);
+		assertThat(testBean.getMessageText()).isNull();
 		MessageChannel testChannel = (MessageChannel) context.getBean("testChannel");
 		testChannel.send(new GenericMessage<>("test-123"));
 		latch.await(1000, TimeUnit.MILLISECONDS);
-		assertEquals(0, latch.getCount());
-		assertEquals("test-123", testBean.getMessageText());
+		assertThat(latch.getCount()).isEqualTo(0);
+		assertThat(testBean.getMessageText()).isEqualTo("test-123");
 		context.close();
 	}
 

spring-integration-core/src/test/java/org/springframework/integration/config/SourcePollingChannelAdapterFactoryBeanTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2018 the original author or authors.
+ * Copyright 2002-2019 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -16,9 +16,7 @@
 
 package org.springframework.integration.config;
 
-import static org.junit.Assert.assertEquals;
-import static org.junit.Assert.assertNotNull;
-import static org.junit.Assert.assertTrue;
+import static org.assertj.core.api.Assertions.assertThat;
 import static org.mockito.ArgumentMatchers.any;
 import static org.mockito.ArgumentMatchers.contains;
 import static org.mockito.BDDMockito.willAnswer;
@@ -92,8 +90,8 @@ public class SourcePollingChannelAdapterFactoryBeanTests {
 		context.registerEndpoint("testPollingEndpoint", factoryBean.getObject());
 		context.refresh();
 		Message<?> message = outputChannel.receive(5000);
-		assertEquals("test", message.getPayload());
-		assertTrue("adviceChain was not applied", adviceApplied.get());
+		assertThat(message.getPayload()).isEqualTo("test");
+		assertThat(adviceApplied.get()).as("adviceChain was not applied").isTrue();
 		context.close();
 	}
 
@@ -133,9 +131,9 @@ public class SourcePollingChannelAdapterFactoryBeanTests {
 		context.registerEndpoint("testPollingEndpoint", factoryBean.getObject());
 		context.refresh();
 		Message<?> message = outputChannel.receive(5000);
-		assertEquals("test", message.getPayload());
-		assertEquals(1, count.get());
-		assertTrue("adviceChain was not applied", adviceApplied.get());
+		assertThat(message.getPayload()).isEqualTo("test");
+		assertThat(count.get()).isEqualTo(1);
+		assertThat(adviceApplied.get()).as("adviceChain was not applied").isTrue();
 		context.close();
 	}
 
@@ -183,7 +181,7 @@ public class SourcePollingChannelAdapterFactoryBeanTests {
 
 		pollingChannelAdapter.start();
 
-		assertTrue(startLatch.await(10, TimeUnit.SECONDS));
+		assertThat(startLatch.await(10, TimeUnit.SECONDS)).isTrue();
 		pollingChannelAdapter.stop();
 
 		taskScheduler.shutdown();
@@ -215,8 +213,8 @@ public class SourcePollingChannelAdapterFactoryBeanTests {
 		pollingChannelAdapter.start();
 
 		Message<?> receive = outputChannel.receive(10_000);
-		assertNotNull(receive);
-		assertEquals(true, receive.getPayload());
+		assertThat(receive).isNotNull();
+		assertThat(receive.getPayload()).isEqualTo(true);
 		pollingChannelAdapter.stop();
 	}
 

spring-integration-core/src/test/java/org/springframework/integration/config/TopLevelSelectorParserTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2010 the original author or authors.
+ * Copyright 2002-2019 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -16,7 +16,7 @@
 
 package org.springframework.integration.config;
 
-import static org.junit.Assert.assertTrue;
+import static org.assertj.core.api.Assertions.assertThat;
 
 import org.junit.Test;
 import org.junit.runner.RunWith;
@@ -41,7 +41,7 @@ public class TopLevelSelectorParserTests {
 	@Test
 	public void topLevelSelector() {
 		MessageSelector selector = (MessageSelector) context.getBean("selector");
-		assertTrue(selector.accept(new GenericMessage<String>("test")));
+		assertThat(selector.accept(new GenericMessage<String>("test"))).isTrue();
 	}
 
 }

spring-integration-core/src/test/java/org/springframework/integration/config/WireTapParserTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2014 the original author or authors.
+ * Copyright 2002-2019 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -16,11 +16,7 @@
 
 package org.springframework.integration.config;
 
-import static org.hamcrest.Matchers.instanceOf;
-import static org.junit.Assert.assertEquals;
-import static org.junit.Assert.assertNotNull;
-import static org.junit.Assert.assertNull;
-import static org.junit.Assert.assertThat;
+import static org.assertj.core.api.Assertions.assertThat;
 
 import java.util.List;
 
@@ -71,41 +67,41 @@ public class WireTapParserTests {
 
 	@Test
 	public void simpleWireTap() {
-		assertNull(wireTapChannel.receive(0));
+		assertThat(wireTapChannel.receive(0)).isNull();
 		Message<?> original = new GenericMessage<String>("test");
 		noSelectors.send(original);
 		Message<?> intercepted = wireTapChannel.receive(0);
-		assertNotNull(intercepted);
-		assertEquals(original, intercepted);
+		assertThat(intercepted).isNotNull();
+		assertThat(intercepted).isEqualTo(original);
 	}
 
 	@Test
 	public void simpleWireTapWithIdAndSelectorExpression() {
-		assertThat(TestUtils.getPropertyValue(wireTap, "selector"), instanceOf(ExpressionEvaluatingSelector.class));
+		assertThat(TestUtils.getPropertyValue(wireTap, "selector")).isInstanceOf(ExpressionEvaluatingSelector.class);
 		Message<?> original = new GenericMessage<String>("test");
 		withId.send(original);
 		Message<?> intercepted = wireTapChannel.receive(0);
-		assertNotNull(intercepted);
-		assertEquals(original, intercepted);
+		assertThat(intercepted).isNotNull();
+		assertThat(intercepted).isEqualTo(original);
 	}
 
 	@Test
 	public void wireTapWithAcceptingSelector() {
-		assertNull(wireTapChannel.receive(0));
+		assertThat(wireTapChannel.receive(0)).isNull();
 		Message<?> original = new GenericMessage<String>("test");
 		accepting.send(original);
 		Message<?> intercepted = wireTapChannel.receive(0);
-		assertNotNull(intercepted);
-		assertEquals(original, intercepted);
+		assertThat(intercepted).isNotNull();
+		assertThat(intercepted).isEqualTo(original);
 	}
 
 	@Test
 	public void wireTapWithRejectingSelector() {
-		assertNull(wireTapChannel.receive(0));
+		assertThat(wireTapChannel.receive(0)).isNull();
 		Message<?> original = new GenericMessage<String>("test");
 		rejecting.send(original);
 		Message<?> intercepted = wireTapChannel.receive(0);
-		assertNull(intercepted);
+		assertThat(intercepted).isNull();
 	}
 
 	@Test
@@ -125,9 +121,9 @@ public class WireTapParserTests {
 				otherTimeoutCount++;
 			}
 		}
-		assertEquals(4, defaultTimeoutCount);
-		assertEquals(1, expectedTimeoutCount);
-		assertEquals(0, otherTimeoutCount);
+		assertThat(defaultTimeoutCount).isEqualTo(4);
+		assertThat(expectedTimeoutCount).isEqualTo(1);
+		assertThat(otherTimeoutCount).isEqualTo(0);
 	}
 
 }

spring-integration-core/src/test/java/org/springframework/integration/config/annotation/AggregatorAnnotationTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2017 the original author or authors.
+ * Copyright 2002-2019 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -16,16 +16,11 @@
 
 package org.springframework.integration.config.annotation;
 
-import static org.junit.Assert.assertEquals;
-import static org.junit.Assert.assertNotNull;
-import static org.junit.Assert.assertNull;
-import static org.junit.Assert.assertSame;
-import static org.junit.Assert.assertTrue;
+import static org.assertj.core.api.Assertions.assertThat;
 import static org.springframework.integration.test.util.TestUtils.getPropertyValue;
 
 import java.lang.reflect.Method;
 
-import org.junit.Assert;
 import org.junit.Test;
 
 import org.springframework.beans.DirectFieldAccessor;
@@ -53,11 +48,12 @@ public class AggregatorAnnotationTests {
 				new String[] { "classpath:/org/springframework/integration/config/annotation/testAnnotatedAggregator.xml" });
 		final String endpointName = "endpointWithDefaultAnnotation";
 		MessageHandler aggregator = this.getAggregator(context, endpointName);
-		assertTrue(getPropertyValue(aggregator, "releaseStrategy") instanceof SimpleSequenceSizeReleaseStrategy);
-		assertNull(getPropertyValue(aggregator, "outputChannel"));
-		assertTrue(getPropertyValue(aggregator, "discardChannel") instanceof NullChannel);
-		assertEquals(-1L, getPropertyValue(aggregator, "messagingTemplate.sendTimeout"));
-		assertEquals(false, getPropertyValue(aggregator, "sendPartialResultOnExpiry"));
+		assertThat(getPropertyValue(aggregator, "releaseStrategy") instanceof SimpleSequenceSizeReleaseStrategy)
+				.isTrue();
+		assertThat(getPropertyValue(aggregator, "outputChannel")).isNull();
+		assertThat(getPropertyValue(aggregator, "discardChannel") instanceof NullChannel).isTrue();
+		assertThat(getPropertyValue(aggregator, "messagingTemplate.sendTimeout")).isEqualTo(-1L);
+		assertThat(getPropertyValue(aggregator, "sendPartialResultOnExpiry")).isEqualTo(false);
 		context.close();
 	}
 
@@ -67,11 +63,12 @@ public class AggregatorAnnotationTests {
 				new String[] { "classpath:/org/springframework/integration/config/annotation/testAnnotatedAggregator.xml" });
 		final String endpointName = "endpointWithCustomizedAnnotation";
 		MessageHandler aggregator = this.getAggregator(context, endpointName);
-		assertTrue(getPropertyValue(aggregator, "releaseStrategy") instanceof SimpleSequenceSizeReleaseStrategy);
-		assertEquals("outputChannel", getPropertyValue(aggregator, "outputChannelName"));
-		assertEquals("discardChannel", getPropertyValue(aggregator, "discardChannelName"));
-		assertEquals(98765432L, getPropertyValue(aggregator, "messagingTemplate.sendTimeout"));
-		assertEquals(true, getPropertyValue(aggregator, "sendPartialResultOnExpiry"));
+		assertThat(getPropertyValue(aggregator, "releaseStrategy") instanceof SimpleSequenceSizeReleaseStrategy)
+				.isTrue();
+		assertThat(getPropertyValue(aggregator, "outputChannelName")).isEqualTo("outputChannel");
+		assertThat(getPropertyValue(aggregator, "discardChannelName")).isEqualTo("discardChannel");
+		assertThat(getPropertyValue(aggregator, "messagingTemplate.sendTimeout")).isEqualTo(98765432L);
+		assertThat(getPropertyValue(aggregator, "sendPartialResultOnExpiry")).isEqualTo(true);
 		context.close();
 	}
 
@@ -82,14 +79,14 @@ public class AggregatorAnnotationTests {
 		final String endpointName = "endpointWithDefaultAnnotationAndCustomReleaseStrategy";
 		MessageHandler aggregator = this.getAggregator(context, endpointName);
 		Object releaseStrategy = getPropertyValue(aggregator, "releaseStrategy");
-		Assert.assertTrue(releaseStrategy instanceof MethodInvokingReleaseStrategy);
+		assertThat(releaseStrategy instanceof MethodInvokingReleaseStrategy).isTrue();
 		MethodInvokingReleaseStrategy releaseStrategyAdapter = (MethodInvokingReleaseStrategy) releaseStrategy;
 		Object handlerMethods = new DirectFieldAccessor(releaseStrategyAdapter)
 				.getPropertyValue("adapter.delegate.handlerMethods");
-		assertNull(handlerMethods);
+		assertThat(handlerMethods).isNull();
 		Object handlerMethod = new DirectFieldAccessor(releaseStrategyAdapter)
 				.getPropertyValue("adapter.delegate.handlerMethod");
-		assertTrue(handlerMethod.toString().contains("completionChecker"));
+		assertThat(handlerMethod.toString().contains("completionChecker")).isTrue();
 		context.close();
 	}
 
@@ -100,18 +97,19 @@ public class AggregatorAnnotationTests {
 		final String endpointName = "endpointWithCorrelationStrategy";
 		MessageHandler aggregator = this.getAggregator(context, endpointName);
 		Object correlationStrategy = getPropertyValue(aggregator, "correlationStrategy");
-		Assert.assertTrue(correlationStrategy instanceof MethodInvokingCorrelationStrategy);
+		assertThat(correlationStrategy instanceof MethodInvokingCorrelationStrategy).isTrue();
 		MethodInvokingCorrelationStrategy releaseStrategyAdapter = (MethodInvokingCorrelationStrategy) correlationStrategy;
 		DirectFieldAccessor processorAccessor = new DirectFieldAccessor(new DirectFieldAccessor(new DirectFieldAccessor(releaseStrategyAdapter)
 				.getPropertyValue("processor")).getPropertyValue("delegate"));
 		Object targetObject = processorAccessor.getPropertyValue("targetObject");
-		assertSame(context.getBean(endpointName), targetObject);
-		assertNull(processorAccessor.getPropertyValue("handlerMethods"));
+		assertThat(targetObject).isSameAs(context.getBean(endpointName));
+		assertThat(processorAccessor.getPropertyValue("handlerMethods")).isNull();
 		Object handlerMethod = processorAccessor.getPropertyValue("handlerMethod");
-		assertNotNull(handlerMethod);
+		assertThat(handlerMethod).isNotNull();
 		DirectFieldAccessor handlerMethodAccessor = new DirectFieldAccessor(handlerMethod);
-		Method completionCheckerMethod = (Method) handlerMethodAccessor.getPropertyValue("invocableHandlerMethod.method");
-		assertEquals("correlate", completionCheckerMethod.getName());
+		Method completionCheckerMethod = (Method) handlerMethodAccessor.getPropertyValue(
+				"invocableHandlerMethod.method");
+		assertThat(completionCheckerMethod.getName()).isEqualTo("correlate");
 		context.close();
 	}
 

spring-integration-core/src/test/java/org/springframework/integration/config/annotation/AnnotatedEndpointActivationTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2018 the original author or authors.
+ * Copyright 2002-2019 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -16,9 +16,7 @@
 
 package org.springframework.integration.config.annotation;
 
-import static org.junit.Assert.assertEquals;
-import static org.junit.Assert.assertNotNull;
-import static org.junit.Assert.assertTrue;
+import static org.assertj.core.api.Assertions.assertThat;
 
 import org.junit.Before;
 import org.junit.Test;
@@ -83,21 +81,21 @@ public class AnnotatedEndpointActivationTests {
 	public void sendAndReceive() {
 		this.input.send(new GenericMessage<>("foo"));
 		Message<?> message = this.output.receive(100);
-		assertNotNull(message);
-		assertEquals("foo: 1", message.getPayload());
-		assertEquals(1, count);
+		assertThat(message).isNotNull();
+		assertThat(message.getPayload()).isEqualTo("foo: 1");
+		assertThat(count).isEqualTo(1);
 
-		assertTrue(this.applicationContext.containsBean("annotatedEndpoint.process.serviceActivator"));
-		assertTrue(this.applicationContext.containsBean("annotatedEndpoint2.process.serviceActivator"));
+		assertThat(this.applicationContext.containsBean("annotatedEndpoint.process.serviceActivator")).isTrue();
+		assertThat(this.applicationContext.containsBean("annotatedEndpoint2.process.serviceActivator")).isTrue();
 	}
 
 	@Test
 	public void sendAndReceiveAsync() {
 		this.inputAsync.send(new GenericMessage<>("foo"));
 		Message<?> message = this.outputAsync.receive(100);
-		assertNotNull(message);
-		assertEquals("foo", message.getPayload());
-		assertTrue(this.applicationContext.containsBean("annotatedEndpoint3.process.serviceActivator"));
+		assertThat(message).isNotNull();
+		assertThat(message.getPayload()).isEqualTo("foo");
+		assertThat(this.applicationContext.containsBean("annotatedEndpoint3.process.serviceActivator")).isTrue();
 	}
 
 	@Test
@@ -105,9 +103,9 @@ public class AnnotatedEndpointActivationTests {
 		MessageChannel input = this.applicationContext.getBean("inputImplicit", MessageChannel.class);
 		input.send(new GenericMessage<>("foo"));
 		Message<?> message = this.output.receive(100);
-		assertNotNull(message);
-		assertEquals("foo: 1", message.getPayload());
-		assertEquals(1, count);
+		assertThat(message).isNotNull();
+		assertThat(message.getPayload()).isEqualTo("foo: 1");
+		assertThat(count).isEqualTo(1);
 	}
 
 	@Test(expected = MessageDeliveryException.class)
@@ -124,9 +122,9 @@ public class AnnotatedEndpointActivationTests {
 		applicationContext.start();
 		this.input.send(new GenericMessage<>("foo"));
 		Message<?> message = this.output.receive(100);
-		assertNotNull(message);
-		assertEquals("foo: 1", message.getPayload());
-		assertEquals(1, count);
+		assertThat(message).isNotNull();
+		assertThat(message.getPayload()).isEqualTo("foo: 1");
+		assertThat(count).isEqualTo(1);
 	}
 
 	@MessageEndpoint