Fix non self-contained aggregate application binding

- Remove conditionalOnMissingBean check on the necessary beans that are required for exernal bindings of the child application
 - Add test to verify

Resolves #816

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

@@ -0,0 +1,54 @@
+/*
+ * 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.config.aggregate;
+
+import java.util.concurrent.TimeUnit;
+
+import org.junit.Assert;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+
+import org.springframework.cloud.stream.aggregate.AggregateApplicationBuilder;
+import org.springframework.cloud.stream.binder.BinderFactory;
+import org.springframework.cloud.stream.config.aggregate.processor.TestProcessor;
+import org.springframework.cloud.stream.config.aggregate.source.TestSource;
+import org.springframework.cloud.stream.test.binder.TestSupportBinder;
+import org.springframework.cloud.stream.test.binder.TestSupportBinderAutoConfiguration;
+import org.springframework.context.ConfigurableApplicationContext;
+import org.springframework.messaging.Message;
+import org.springframework.messaging.MessageChannel;
+import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;
+
+import static org.hamcrest.Matchers.notNullValue;
+
+/**
+ * @author Ilayaperumal Gopinathan
+ */
+@RunWith(SpringJUnit4ClassRunner.class)
+public class AggregateApplicationTests {
+
+	@Test
+	@SuppressWarnings("unchecked")
+	public void testAggregateApplication() throws Exception {
+		ConfigurableApplicationContext context = new AggregateApplicationBuilder(TestSupportBinderAutoConfiguration.class).from(TestSource.class).to(TestProcessor.class).run();
+		TestSupportBinder testSupportBinder = (TestSupportBinder) context.getBean(BinderFactory.class).getBinder(null, MessageChannel.class);
+		MessageChannel processorOutput = testSupportBinder.getChannelForName("output");
+		Message<String> received = (Message<String>) (testSupportBinder.messageCollector().forChannel(processorOutput).poll(5, TimeUnit.SECONDS));
+		Assert.assertThat(received, notNullValue());
+		Assert.assertTrue(received.getPayload().endsWith("processed"));
+	}
+}

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

@@ -0,0 +1,39 @@
+/*
+ * 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.config.aggregate.processor;
+
+import org.springframework.boot.autoconfigure.EnableAutoConfiguration;
+import org.springframework.cloud.stream.annotation.EnableBinding;
+import org.springframework.cloud.stream.annotation.StreamListener;
+import org.springframework.cloud.stream.messaging.Processor;
+import org.springframework.context.annotation.Configuration;
+import org.springframework.messaging.handler.annotation.SendTo;
+
+/**
+ * @author Ilayaperumal Gopinathan
+ */
+@EnableBinding(Processor.class)
+@EnableAutoConfiguration
+@Configuration
+public class TestProcessor {
+
+	@StreamListener(Processor.INPUT)
+	@SendTo(Processor.OUTPUT)
+	public String process(String message) {
+		return message + " processed";
+	}
+}

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

@@ -0,0 +1,50 @@
+/*
+ * 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.config.aggregate.source;
+
+import java.text.SimpleDateFormat;
+import java.util.Date;
+
+import org.springframework.boot.autoconfigure.EnableAutoConfiguration;
+import org.springframework.cloud.stream.annotation.EnableBinding;
+import org.springframework.cloud.stream.messaging.Source;
+import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.Configuration;
+import org.springframework.integration.annotation.InboundChannelAdapter;
+import org.springframework.integration.core.MessageSource;
+import org.springframework.messaging.Message;
+import org.springframework.messaging.support.GenericMessage;
+
+/**
+ * @author Ilayaperumal Gopinathan
+ */
+@EnableBinding(Source.class)
+@EnableAutoConfiguration
+@Configuration
+public class TestSource {
+
+	@Bean
+	@InboundChannelAdapter(Source.OUTPUT)
+	public MessageSource<String> timerMessageSource() {
+		return new MessageSource<String>() {
+			@Override
+			public Message<String> receive() {
+				return new GenericMessage<>(new SimpleDateFormat("DDMMMYYYY").format(new Date()));
+			}
+		};
+	}
+}