BATCH-2686: Add assertions on input/output channels

Author: fmbenhassine

spring-batch-integration/src/main/java/org/springframework/batch/integration/chunk/RemoteChunkingMasterStepBuilder.java

@@ -180,8 +180,8 @@ public RemoteChunkingMasterStepBuilder<I, O> throttleLimit(long throttleLimit) {
 	public TaskletStep build() {
 
 		Assert.notNull(beanDefinitionRegistry, "A BeanDefinitionRegistry must be provided");
-		Assert.notNull(inputChannel, "inputChannel must not be null");
-		Assert.notNull(outputChannel, "outputChannel must not be null");
+		Assert.notNull(inputChannel, "An InputChannel must be provided");
+		Assert.notNull(outputChannel, "An OutputChannel must be provided");
 
 		// configure messaging template
 		if (this.messagingTemplate == null) {

spring-batch-integration/src/main/java/org/springframework/batch/integration/chunk/RemoteChunkingWorkerBuilder.java

@@ -112,6 +112,8 @@ public RemoteChunkingWorkerBuilder<I, O> outputChannel(DirectChannel outputChann
 	public IntegrationFlow build() {
 
 		Assert.notNull(itemWriter, "An ItemWriter must be provided");
+		Assert.notNull(inputChannel, "An InputChannel must be provided");
+		Assert.notNull(outputChannel, "An OutputChannel must be provided");
 
 		if(this.itemProcessor == null) {
 			this.itemProcessor = new PassThroughItemProcessor();

spring-batch-integration/src/test/java/org/springframework/batch/integration/chunk/RemoteChunkingMasterStepBuilderTest.java

@@ -159,6 +159,39 @@ public void throttleLimitMustNotBeGreaterThanZero() {
 		// expected exception
 	}
 
+	@Test
+	public void testMandatoryInputChannel() {
+		// given
+		RemoteChunkingMasterStepBuilder<String, String> builder = new RemoteChunkingMasterStepBuilder<String, String>("step")
+				.beanDefinitionRegistry(new GenericApplicationContext());
+
+		expectedException.expect(IllegalArgumentException.class);
+		expectedException.expectMessage("An InputChannel must be provided");
+
+		// when
+		TaskletStep step = builder.build();
+
+		// then
+		// expected exception
+	}
+
+	@Test
+	public void testMandatoryOutputChannel() {
+		// given
+		RemoteChunkingMasterStepBuilder<String, String> builder = new RemoteChunkingMasterStepBuilder<String, String>("step")
+				.beanDefinitionRegistry(new GenericApplicationContext())
+				.inputChannel(new QueueChannel());
+
+		expectedException.expect(IllegalArgumentException.class);
+		expectedException.expectMessage("An OutputChannel must be provided");
+
+		// when
+		TaskletStep step = builder.build();
+
+		// then
+		// expected exception
+	}
+
 	@Test
 	public void testRemoteChunkHandlerRegistration() {
 		// given

spring-batch-integration/src/test/java/org/springframework/batch/integration/chunk/RemoteChunkingWorkerBuilderTest.java

@@ -111,6 +111,39 @@ public void testMandatoryItemWriter() {
 		// expected exception
 	}
 
+	@Test
+	public void testMandatoryInputChannel() {
+		// given
+		RemoteChunkingWorkerBuilder<String, String> builder = new RemoteChunkingWorkerBuilder<String, String>()
+				.itemWriter(items -> { });
+
+		expectedException.expect(IllegalArgumentException.class);
+		expectedException.expectMessage("An InputChannel must be provided");
+
+		// when
+		builder.build();
+
+		// then
+		// expected exception
+	}
+
+	@Test
+	public void testMandatoryOutputChannel() {
+		// given
+		RemoteChunkingWorkerBuilder<String, String> builder = new RemoteChunkingWorkerBuilder<String, String>()
+				.itemWriter(items -> { })
+				.inputChannel(new DirectChannel());
+
+		expectedException.expect(IllegalArgumentException.class);
+		expectedException.expectMessage("An OutputChannel must be provided");
+
+		// when
+		builder.build();
+
+		// then
+		// expected exception
+	}
+
 	@Test
 	public void testIntegrationFlowCreation() {
 		// given