Use assertThat from Hamcrest instead of JUnit 4

org.junit.Assert.assertThat() is deprecated as of JUnit 4.13.

See gh-22894

spring-messaging/src/test/java/org/springframework/messaging/converter/MappingJackson2MessageConverterTests.java

@@ -33,6 +33,7 @@ import org.springframework.messaging.MessageHeaders;
 import org.springframework.messaging.support.MessageBuilder;
 import org.springframework.util.MimeType;
 
+import static org.hamcrest.MatcherAssert.assertThat;
 import static org.hamcrest.Matchers.*;
 import static org.junit.Assert.*;
 

spring-messaging/src/test/java/org/springframework/messaging/converter/MarshallingMessageConverterTests.java

@@ -16,6 +16,7 @@
 
 package org.springframework.messaging.converter;
 
+import static org.hamcrest.MatcherAssert.assertThat;
 import static org.junit.Assert.*;
 import static org.xmlunit.diff.ComparisonType.*;
 import static org.xmlunit.diff.DifferenceEvaluators.*;

spring-messaging/src/test/java/org/springframework/messaging/handler/invocation/InvocableHandlerMethodTests.java

@@ -24,6 +24,7 @@ import org.springframework.core.MethodParameter;
 import org.springframework.lang.Nullable;
 import org.springframework.messaging.Message;
 
+import static org.hamcrest.MatcherAssert.assertThat;
 import static org.hamcrest.Matchers.*;
 import static org.junit.Assert.*;
 import static org.mockito.Mockito.*;

spring-messaging/src/test/java/org/springframework/messaging/handler/invocation/MethodMessageHandlerTests.java

@@ -41,6 +41,7 @@ import org.springframework.util.AntPathMatcher;
 import org.springframework.util.Assert;
 import org.springframework.util.PathMatcher;
 
+import static org.hamcrest.MatcherAssert.assertThat;
 import static org.junit.Assert.*;
 
 /**

spring-messaging/src/test/java/org/springframework/messaging/handler/invocation/reactive/MethodMessageHandlerTests.java

@@ -45,6 +45,7 @@ import org.springframework.util.Assert;
 import org.springframework.util.ClassUtils;
 import org.springframework.util.PathMatcher;
 
+import static org.hamcrest.MatcherAssert.assertThat;
 import static org.junit.Assert.*;
 
 /**

spring-messaging/src/test/java/org/springframework/messaging/simp/SimpAttributesTests.java

@@ -25,8 +25,8 @@ import org.junit.Test;
 import org.junit.rules.ExpectedException;
 import org.mockito.Mockito;
 
+import static org.hamcrest.MatcherAssert.assertThat;
 import static org.hamcrest.Matchers.*;
-import static org.junit.Assert.*;
 import static org.mockito.Mockito.*;
 
 /**

spring-messaging/src/test/java/org/springframework/messaging/simp/SimpSessionScopeTests.java

@@ -25,8 +25,8 @@ import org.mockito.Mockito;
 
 import org.springframework.beans.factory.ObjectFactory;
 
+import static org.hamcrest.MatcherAssert.assertThat;
 import static org.hamcrest.Matchers.*;
-import static org.junit.Assert.*;
 import static org.mockito.BDDMockito.*;
 
 /**

spring-messaging/src/test/java/org/springframework/messaging/simp/annotation/support/SimpAnnotationMethodMessageHandlerTests.java

@@ -67,6 +67,7 @@ import org.springframework.validation.Errors;
 import org.springframework.validation.Validator;
 import org.springframework.validation.annotation.Validated;
 
+import static org.hamcrest.MatcherAssert.assertThat;
 import static org.hamcrest.Matchers.*;
 import static org.junit.Assert.*;
 import static org.mockito.BDDMockito.any;

spring-messaging/src/test/java/org/springframework/messaging/simp/config/MessageBrokerConfigurationTests.java

@@ -77,6 +77,7 @@ import org.springframework.validation.Errors;
 import org.springframework.validation.Validator;
 import org.springframework.validation.beanvalidation.OptionalValidatorFactoryBean;
 
+import static org.hamcrest.MatcherAssert.assertThat;
 import static org.junit.Assert.*;
 import static org.mockito.Mockito.*;
 

spring-messaging/src/test/java/org/springframework/messaging/simp/stomp/DefaultStompSessionTests.java

@@ -46,6 +46,7 @@ import org.springframework.util.MimeType;
 import org.springframework.util.MimeTypeUtils;
 import org.springframework.util.concurrent.SettableListenableFuture;
 
+import static org.hamcrest.MatcherAssert.assertThat;
 import static org.hamcrest.Matchers.*;
 import static org.junit.Assert.*;
 import static org.mockito.Mockito.any;

spring-messaging/src/test/java/org/springframework/messaging/simp/stomp/ReactorNettyTcpStompClientTests.java

@@ -40,6 +40,7 @@ import org.springframework.util.Assert;
 import org.springframework.util.SocketUtils;
 import org.springframework.util.concurrent.ListenableFuture;
 
+import static org.hamcrest.MatcherAssert.assertThat;
 import static org.hamcrest.Matchers.*;
 import static org.junit.Assert.*;
 

spring-messaging/src/test/java/org/springframework/messaging/simp/stomp/StompHeaderAccessorTests.java

@@ -37,6 +37,7 @@ import org.springframework.util.MimeType;
 import org.springframework.util.MimeTypeUtils;
 import org.springframework.util.MultiValueMap;
 
+import static org.hamcrest.MatcherAssert.assertThat;
 import static org.junit.Assert.*;
 
 /**

spring-messaging/src/test/java/org/springframework/messaging/simp/user/MultiServerUserRegistryTests.java

@@ -16,6 +16,7 @@
 
 package org.springframework.messaging.simp.user;
 
+import static org.hamcrest.MatcherAssert.assertThat;
 import static org.hamcrest.Matchers.containsInAnyOrder;
 import static org.junit.Assert.*;
 import static org.mockito.Mockito.*;

spring-messaging/src/test/java/org/springframework/messaging/support/ErrorMessageTests.java

@@ -19,7 +19,7 @@ package org.springframework.messaging.support;
 import org.junit.Test;
 
 import static org.hamcrest.CoreMatchers.*;
-import static org.junit.Assert.*;
+import static org.hamcrest.MatcherAssert.assertThat;
 
 /**
  * @author Gary Russell

spring-messaging/src/test/java/org/springframework/messaging/support/ExecutorSubscribableChannelTests.java

@@ -33,6 +33,7 @@ import org.springframework.messaging.MessageChannel;
 import org.springframework.messaging.MessageDeliveryException;
 import org.springframework.messaging.MessageHandler;
 
+import static org.hamcrest.MatcherAssert.assertThat;
 import static org.hamcrest.Matchers.*;
 import static org.junit.Assert.*;
 import static org.mockito.BDDMockito.*;

spring-messaging/src/test/java/org/springframework/messaging/support/MessageHeaderAccessorTests.java

@@ -32,13 +32,13 @@ import org.springframework.util.MimeTypeUtils;
 import org.springframework.util.SerializationTestUtils;
 
 import static org.hamcrest.CoreMatchers.startsWith;
+import static org.hamcrest.MatcherAssert.assertThat;
 import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertFalse;
 import static org.junit.Assert.assertNotEquals;
 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;
 
 /**