Improve support for disabling TestSupportBinderAutoConfiguration

Fixes #573

- Split TestSupportBinderAutoConfiguration into separate configs
  for the binder, binderfactory and message collector.
  This enables to address the testBinder as a regular binder when
  autoconfiguration is disabled, and to ensure that the message
  collector is available when the autoconfiguration is disabled.
- reorganize tests to use the default autoconfiguration options
- add documentation for disabling test binder autoconfiguration

spring-cloud-stream-test-support/src/main/java/org/springframework/cloud/stream/test/binder/MessageCollectorAutoConfiguration.java

@@ -0,0 +1,38 @@
+/*
+ * Copyright 2017 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.test.binder;
+
+import org.springframework.cloud.stream.binder.BinderFactory;
+import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.Configuration;
+import org.springframework.messaging.MessageChannel;
+
+/**
+ * Automatically registers the {@link MessageCollector} associated with the test binder as
+ * a bean.
+ *
+ * @author Marius Bogoevici
+ */
+@Configuration
+public class MessageCollectorAutoConfiguration {
+
+	@Bean
+	public MessageCollector messageCollector(BinderFactory binderFactory) {
+		return ((TestSupportBinder) binderFactory.getBinder("test", MessageChannel.class)).messageCollector();
+	}
+
+}

spring-cloud-stream-test-support/src/main/java/org/springframework/cloud/stream/test/binder/TestSupportBinderAutoConfiguration.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2015 the original author or authors.
+ * Copyright 2015-2017 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.
@@ -23,6 +23,7 @@ import org.springframework.cloud.stream.binder.ConsumerProperties;
 import org.springframework.cloud.stream.binder.ProducerProperties;
 import org.springframework.context.annotation.Bean;
 import org.springframework.context.annotation.Configuration;
+import org.springframework.context.annotation.Import;
 import org.springframework.core.Ordered;
 import org.springframework.messaging.MessageChannel;
 
@@ -34,29 +35,24 @@ import org.springframework.messaging.MessageChannel;
  * configuration, so adding this on the classpath in test scope is sufficient to have
  * support kick in and replace all binders with the test binder.
  *
+ * The test binder instance is supplied by the {@link TestSupportBinderConfiguration}.
+ *
  * @author Eric Bottard
  * @author Marius Bogoevici
  */
 @Configuration
 @AutoConfigureOrder(Ordered.HIGHEST_PRECEDENCE)
+@Import(TestSupportBinderConfiguration.class)
 public class TestSupportBinderAutoConfiguration {
 
-	private Binder<MessageChannel, ?, ?> messageChannelBinder = new TestSupportBinder();
-
 	@Bean
-	public BinderFactory binderFactory() {
+	public BinderFactory binderFactory(final Binder<MessageChannel, ?, ?> binder) {
 		return new BinderFactory() {
 			@Override
 			public <T> Binder<T, ? extends ConsumerProperties, ? extends ProducerProperties> getBinder(
 					String configurationName, Class<? extends T> bindableType) {
-				return (Binder<T, ? extends ConsumerProperties, ? extends ProducerProperties>) messageChannelBinder;
+				return (Binder<T, ? extends ConsumerProperties, ? extends ProducerProperties>) binder;
 			}
 		};
 	}
-
-	@Bean
-	public MessageCollector messageCollector(BinderFactory binderFactory) {
-		return ((TestSupportBinder) binderFactory.getBinder(null, MessageChannel.class)).messageCollector();
-	}
-
 }

spring-cloud-stream-test-support/src/main/java/org/springframework/cloud/stream/test/binder/TestSupportBinderConfiguration.java

@@ -0,0 +1,44 @@
+/*
+ * Copyright 2017 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.test.binder;
+
+import org.springframework.cloud.stream.binder.Binder;
+import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.Configuration;
+import org.springframework.messaging.MessageChannel;
+
+/**
+ * Binder {@link org.springframework.context.annotation.Configuration} for the
+ * {@link @TestBinder}.
+ *
+ * Either imported by the {@link TestSupportBinderAutoConfiguration} for the test binder
+ * default usage scenario (superseding all binders on the classpath), or used as a binder
+ * configuration on the classpath when test binder autoconfiguration is disabled.
+ *
+ * @author Marius Bogoevici
+ */
+@Configuration
+public class TestSupportBinderConfiguration {
+
+	private Binder<MessageChannel, ?, ?> messageChannelBinder = new TestSupportBinder();
+
+	@Bean
+	public Binder<MessageChannel, ?, ?> binder() {
+		return messageChannelBinder;
+	}
+
+}

spring-cloud-stream-test-support/src/main/resources/META-INF/spring.binders

@@ -1,2 +1,2 @@
 test:\
-org.springframework.cloud.stream.test.binder.TestSupportBinderAutoConfiguration
+org.springframework.cloud.stream.test.binder.TestSupportBinderConfiguration

spring-cloud-stream-test-support/src/main/resources/META-INF/spring.factories

@@ -1,4 +1,5 @@
-org.springframework.boot.autoconfigure.EnableAutoConfiguration:\
-org.springframework.cloud.stream.test.binder.TestSupportBinderAutoConfiguration
+org.springframework.boot.autoconfigure.EnableAutoConfiguration=\
+org.springframework.cloud.stream.test.binder.TestSupportBinderAutoConfiguration,\
+org.springframework.cloud.stream.test.binder.MessageCollectorAutoConfiguration
 org.springframework.boot.env.EnvironmentPostProcessor=\
   org.springframework.cloud.stream.test.binder.TestBinderEnvironmentPostProcessor