Fix aggregated application behavior

* After moving some bunch of beans from the `@EnableBinding` to the
auto-configuration for proper conditional lifecycle we need to be sure
that all those support beans are registered for each child context as
it was before after parsing imports on the `@EnableBinding`.
This way add `search = SearchStrategy.CURRENT` for all the conditions
in the `BindingServiceConfiguration`
* Fix `TestSupportBinderConfiguration` to rely only on the `Binder`
instance created once in the parent level.
This way when we use an aggregated application, only the parent context
creates for us a `TestSupportBinder` and all the child contexts reuse it.
* Register `BinderFactory` only once in parent ctx

spring-cloud-stream-integration-tests/src/test/java/org/springframework/cloud/stream/config/aggregate/AggregateApplicationTests.java

@@ -57,6 +57,8 @@ public class AggregateApplicationTests {
 				.poll(5, TimeUnit.SECONDS));
 		Assert.assertThat(received, notNullValue());
 		Assert.assertTrue(received.getPayload().endsWith("processed"));
+
+		context.close();
 	}
 
 	@Configuration

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

@@ -16,6 +16,7 @@
 
 package org.springframework.cloud.stream.test.binder;
 
+import org.springframework.boot.autoconfigure.condition.ConditionalOnMissingBean;
 import org.springframework.cloud.stream.binder.Binder;
 import org.springframework.context.annotation.Bean;
 import org.springframework.context.annotation.Configuration;
@@ -32,6 +33,7 @@ import org.springframework.messaging.MessageChannel;
  * @author Marius Bogoevici
  */
 @Configuration
+@ConditionalOnMissingBean(Binder.class)
 public class TestSupportBinderConfiguration {
 
 	private Binder<MessageChannel, ?, ?> messageChannelBinder = new TestSupportBinder();

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

@@ -28,6 +28,7 @@ import org.springframework.beans.factory.annotation.Qualifier;
 import org.springframework.beans.factory.config.BeanDefinition;
 import org.springframework.boot.autoconfigure.condition.ConditionalOnBean;
 import org.springframework.boot.autoconfigure.condition.ConditionalOnMissingBean;
+import org.springframework.boot.autoconfigure.condition.SearchStrategy;
 import org.springframework.boot.context.properties.EnableConfigurationProperties;
 import org.springframework.cloud.stream.binder.BinderConfiguration;
 import org.springframework.cloud.stream.binder.BinderFactory;
@@ -89,7 +90,7 @@ import org.springframework.util.Assert;
 @EnableConfigurationProperties({ BindingServiceProperties.class, SpringIntegrationProperties.class })
 @Import({ContentTypeConfiguration.class, DestinationPublishingMetricsAutoConfiguration.class, SpelExpressionConverterConfiguration.class})
 @Role(BeanDefinition.ROLE_INFRASTRUCTURE)
-@ConditionalOnBean(BinderTypeRegistry.class)
+@ConditionalOnBean(value = BinderTypeRegistry.class, search = SearchStrategy.CURRENT)
 public class BindingServiceConfiguration {
 
 	public static final String STREAM_LISTENER_ANNOTATION_BEAN_POST_PROCESSOR_NAME =
@@ -168,7 +169,7 @@ public class BindingServiceConfiguration {
 	}
 
 	@Bean(name = STREAM_LISTENER_ANNOTATION_BEAN_POST_PROCESSOR_NAME)
-	@ConditionalOnMissingBean
+	@ConditionalOnMissingBean(search = SearchStrategy.CURRENT)
 	public static StreamListenerAnnotationBeanPostProcessor streamListenerAnnotationBeanPostProcessor() {
 		return new StreamListenerAnnotationBeanPostProcessor();
 	}
@@ -177,7 +178,7 @@ public class BindingServiceConfiguration {
 	// This conditional is intentionally not in an autoconfig (usually a bad idea) because
 	// it is used to detect a BindingService in the parent context (which we know
 	// already exists).
-	@ConditionalOnMissingBean
+	@ConditionalOnMissingBean(search = SearchStrategy.CURRENT)
 	public BindingService bindingService(BindingServiceProperties bindingServiceProperties,
 			BinderFactory binderFactory, TaskScheduler taskScheduler) {
 		return new BindingService(bindingServiceProperties, binderFactory, taskScheduler);