Separate error channel tests, some cleanup

spring-cloud-stream/src/main/java/org/springframework/cloud/stream/annotation/EnableBinding.java

@@ -31,7 +31,7 @@ import org.springframework.context.annotation.Import;
 import org.springframework.integration.config.EnableIntegration;
 
 /**
- * Enables the binding of {@link Input} and {@link Output} - annotated components to a broker, according to the list
+ * Enables the binding of components annotated with {@link Input} and {@link Output} to a broker, according to the list
  * of interfaces passed as value to the annotation.
  *
  * @author Dave Syer

spring-cloud-stream/src/main/java/org/springframework/cloud/stream/binding/BindableAdapter.java

@@ -44,11 +44,11 @@ public class BindableAdapter implements Bindable {
 
 	@Override
 	public Set<String> getInputs() {
-		return Collections.unmodifiableSet(Collections.EMPTY_SET);
+		return Collections.emptySet();
 	}
 
 	@Override
 	public Set<String> getOutputs() {
-		return Collections.unmodifiableSet(Collections.EMPTY_SET);
+		return Collections.emptySet();
 	}
 }

spring-cloud-stream/src/main/java/org/springframework/cloud/stream/binding/SingleChannelBindable.java

@@ -23,17 +23,19 @@ import java.util.Set;
 import org.springframework.integration.channel.PublishSubscribeChannel;
 
 /**
- * A {@link Bindable} component that represents an error channel.
+ * A {@link Bindable} component that wraps a generic channel. Useful for binding channels outside the
+ * {@link org.springframework.cloud.stream.annotation.Input} and {@link org.springframework.cloud.stream.annotation.Output}
+ * annotated interfaces.
  *
  * @author Ilayaperumal Gopinathan
  */
-public class BindableErrorChannel extends BindableAdapter {
+public class SingleChannelBindable extends BindableAdapter {
 
 	private final String name;
 
 	private final PublishSubscribeChannel errorChannel;
 
-	public BindableErrorChannel(String name, PublishSubscribeChannel errorChannel) {
+	public SingleChannelBindable(String name, PublishSubscribeChannel errorChannel) {
 		this.name = name;
 		this.errorChannel = errorChannel;
 	}

spring-cloud-stream/src/main/java/org/springframework/cloud/stream/config/ChannelBindingServiceConfiguration.java

@@ -33,7 +33,6 @@ import org.springframework.boot.context.properties.ConfigurationPropertiesBindin
 import org.springframework.boot.context.properties.EnableConfigurationProperties;
 import org.springframework.cloud.stream.binder.BinderFactory;
 import org.springframework.cloud.stream.binding.BindableChannelFactory;
-import org.springframework.cloud.stream.binding.BindableErrorChannel;
 import org.springframework.cloud.stream.binding.BinderAwareChannelResolver;
 import org.springframework.cloud.stream.binding.BinderAwareRouterBeanPostProcessor;
 import org.springframework.cloud.stream.binding.ChannelBindingService;
@@ -45,6 +44,7 @@ import org.springframework.cloud.stream.binding.MessageChannelConfigurer;
 import org.springframework.cloud.stream.binding.MessageConverterConfigurer;
 import org.springframework.cloud.stream.binding.MessageHistoryTrackerConfigurer;
 import org.springframework.cloud.stream.binding.OutputBindingLifecycle;
+import org.springframework.cloud.stream.binding.SingleChannelBindable;
 import org.springframework.context.annotation.Bean;
 import org.springframework.context.annotation.Configuration;
 import org.springframework.context.annotation.DependsOn;
@@ -146,6 +146,13 @@ public class ChannelBindingServiceConfiguration {
 		return new BindingPropertiesConverter();
 	}
 
+	@Bean
+	@ConditionalOnProperty("spring.cloud.stream.bindings." + ERROR_CHANNEL_NAME + ".destination")
+	public SingleChannelBindable errorChannelBindable(
+			@Qualifier(IntegrationContextUtils.ERROR_CHANNEL_BEAN_NAME) PublishSubscribeChannel errorChannel) {
+		return new SingleChannelBindable(ERROR_CHANNEL_NAME, errorChannel);
+	}
+
 	// IMPORTANT: Nested class to avoid instantiating all of the above early
 	@Configuration
 	protected static class PostProcessorConfiguration {
@@ -206,12 +213,4 @@ public class ChannelBindingServiceConfiguration {
 			};
 		}
 	}
-
-	@Bean
-	@ConditionalOnProperty("spring.cloud.stream.bindings." + ERROR_CHANNEL_NAME + ".destination")
-	public BindableErrorChannel bindableErrorChannel(
-			@Qualifier(IntegrationContextUtils.ERROR_CHANNEL_BEAN_NAME) PublishSubscribeChannel errorChannel) {
-		return new BindableErrorChannel(ERROR_CHANNEL_NAME, errorChannel);
-	}
-
 }

spring-cloud-stream/src/test/java/org/springframework/cloud/stream/binder/ErrorBindingTests.java

@@ -0,0 +1,85 @@
+/*
+ * Copyright 2016 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.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.springframework.cloud.stream.binder;
+
+import static org.mockito.Matchers.any;
+import static org.mockito.Matchers.eq;
+import static org.mockito.Matchers.isNull;
+import static org.mockito.Matchers.same;
+
+import java.util.Properties;
+
+import org.junit.Test;
+import org.mockito.Mockito;
+
+import org.springframework.boot.SpringApplication;
+import org.springframework.boot.autoconfigure.EnableAutoConfiguration;
+import org.springframework.cloud.stream.annotation.EnableBinding;
+import org.springframework.cloud.stream.messaging.Processor;
+import org.springframework.cloud.stream.utils.MockBinderRegistryConfiguration;
+import org.springframework.context.ConfigurableApplicationContext;
+import org.springframework.context.annotation.Import;
+import org.springframework.integration.context.IntegrationContextUtils;
+import org.springframework.messaging.MessageChannel;
+
+/**
+ * @author Marius Bogoevici
+ */
+public class ErrorBindingTests {
+
+	@Test
+	public void testErrorChannelNotBoundByDefault() {
+
+		ConfigurableApplicationContext applicationContext = SpringApplication.run(TestProcessor.class, "--server.port=0");
+		BinderFactory<?> binderFactory = applicationContext.getBean(BinderFactory.class);
+
+		@SuppressWarnings("unchecked")
+		Binder<MessageChannel> binder = (Binder<MessageChannel>) binderFactory.getBinder(null);
+
+		Mockito.verify(binder).bindConsumer(eq("input"), isNull(String.class), any(MessageChannel.class), any(Properties.class));
+		Mockito.verify(binder).bindProducer(eq("output"), any(MessageChannel.class), any(Properties.class));
+		Mockito.verifyNoMoreInteractions(binder);
+		applicationContext.close();
+	}
+
+	@Test
+	public void testErrorChannelBoundIfConfigured() {
+
+		ConfigurableApplicationContext applicationContext =
+				SpringApplication.run(TestProcessor.class, "--spring.cloud.stream.bindings.error.destination=foo", "--server.port=0");
+		BinderFactory<?> binderFactory = applicationContext.getBean(BinderFactory.class);
+
+		@SuppressWarnings("unchecked")
+		Binder<MessageChannel> binder = (Binder<MessageChannel>) binderFactory.getBinder(null);
+
+		MessageChannel errorChannel = applicationContext.getBean(IntegrationContextUtils.ERROR_CHANNEL_BEAN_NAME,
+				MessageChannel.class);
+
+		Mockito.verify(binder).bindConsumer(eq("input"), isNull(String.class), any(MessageChannel.class), any(Properties.class));
+		Mockito.verify(binder).bindProducer(eq("output"), any(MessageChannel.class), any(Properties.class));
+		Mockito.verify(binder).bindProducer(eq("foo"), same(errorChannel), any(Properties.class));
+		Mockito.verifyNoMoreInteractions(binder);
+		applicationContext.close();
+	}
+
+	@EnableBinding(Processor.class)
+	@EnableAutoConfiguration
+	@Import(MockBinderRegistryConfiguration.class)
+	public static class TestProcessor {
+
+	}
+}

spring-cloud-stream/src/test/java/org/springframework/cloud/stream/binder/SourceBindingTestsWithBindingTargets.java

@@ -64,7 +64,6 @@ public class SourceBindingTestsWithBindingTargets {
 	public void testSourceOutputChannelBound() {
 		verify(binder).bindProducer(eq("testtock"), eq(testSource.output()), Mockito.<Properties>any());
 		//Check error channel binding
-		verify(binder).bindProducer(eq("error-test"), eq(errorChannel), Mockito.<Properties>any());
 		verifyNoMoreInteractions(binder);
 	}
 

spring-cloud-stream/src/test/java/org/springframework/cloud/stream/utils/MockBinderConfiguration.java

@@ -29,6 +29,6 @@ public class MockBinderConfiguration {
 
 	@Bean
 	public Binder<?> binder() {
-		return Mockito.mock(Binder.class);
+		return Mockito.mock(Binder.class, Mockito.withSettings().defaultAnswer(Mockito.RETURNS_MOCKS));
 	}
 }

spring-cloud-stream/src/test/resources/org/springframework/cloud/stream/binder/source-binding-test.properties

@@ -1,2 +1 @@
 spring.cloud.stream.bindings.output.destination=testtock
-spring.cloud.stream.bindings.error.destination=error-test