Validate callback is always invoked in DMLC#stop

The underlying issue has been fixed in e45d33f and this commit is merely
adding a test of the expected behaviour.

Issue: SPR-14233

Author: snicoll

spring-jms/src/test/java/org/springframework/jms/listener/DefaultMessageListenerContainerTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2014 the original author or authors.
+ * Copyright 2002-2016 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.
@@ -16,6 +16,8 @@
 
 package org.springframework.jms.listener;
 
+import java.util.concurrent.CountDownLatch;
+import java.util.concurrent.TimeUnit;
 import javax.jms.Connection;
 import javax.jms.ConnectionFactory;
 import javax.jms.Destination;
@@ -39,55 +41,76 @@ public class DefaultMessageListenerContainerTests {
 
 	@Test
 	public void applyBackOff() {
-		BackOff mock = mock(BackOff.class);
+		BackOff backOff = mock(BackOff.class);
 		BackOffExecution execution = mock(BackOffExecution.class);
 		given(execution.nextBackOff()).willReturn(BackOffExecution.STOP);
-		given(mock.start()).willReturn(execution);
+		given(backOff.start()).willReturn(execution);
 
-		DefaultMessageListenerContainer container = createContainer(mock, createFailingContainerFactory());
+		DefaultMessageListenerContainer container = createContainer(createFailingContainerFactory());
+		container.setBackOff(backOff);
 		container.start();
 		assertEquals(true, container.isRunning());
 
 		container.refreshConnectionUntilSuccessful();
 
 		assertEquals(false, container.isRunning());
-		verify(mock).start();
+		verify(backOff).start();
 		verify(execution).nextBackOff();
 	}
 
 	@Test
 	public void applyBackOffRetry() {
-		BackOff mock = mock(BackOff.class);
+		BackOff backOff = mock(BackOff.class);
 		BackOffExecution execution = mock(BackOffExecution.class);
 		given(execution.nextBackOff()).willReturn(50L, BackOffExecution.STOP);
-		given(mock.start()).willReturn(execution);
+		given(backOff.start()).willReturn(execution);
 
-		DefaultMessageListenerContainer container = createContainer(mock, createFailingContainerFactory());
+		DefaultMessageListenerContainer container = createContainer(createFailingContainerFactory());
+		container.setBackOff(backOff);
 		container.start();
 		container.refreshConnectionUntilSuccessful();
 
 		assertEquals(false, container.isRunning());
-		verify(mock).start();
+		verify(backOff).start();
 		verify(execution, times(2)).nextBackOff();
 	}
 
 	@Test
 	public void recoverResetBackOff() {
-		BackOff mock = mock(BackOff.class);
+		BackOff backOff = mock(BackOff.class);
 		BackOffExecution execution = mock(BackOffExecution.class);
 		given(execution.nextBackOff()).willReturn(50L, 50L, 50L); // 3 attempts max
-		given(mock.start()).willReturn(execution);
+		given(backOff.start()).willReturn(execution);
 
-		DefaultMessageListenerContainer container = createContainer(mock, createRecoverableContainerFactory(1));
+		DefaultMessageListenerContainer container = createContainer(createRecoverableContainerFactory(1));
+		container.setBackOff(backOff);
 		container.start();
 		container.refreshConnectionUntilSuccessful();
 
 		assertEquals(true, container.isRunning());
-		verify(mock).start();
+		verify(backOff).start();
 		verify(execution, times(1)).nextBackOff(); // only on attempt as the second one lead to a recovery
 	}
 
-	private DefaultMessageListenerContainer createContainer(BackOff backOff, ConnectionFactory connectionFactory) {
+	@Test
+	public void runnableIsInvokedEvenIfContainerIsNotRunning() throws InterruptedException {
+		DefaultMessageListenerContainer container = createRunningContainer();
+		container.stop();
+
+		// container is stopped but should nevertheless invoke the runnable argument
+		TestRunnable runnable2 = new TestRunnable();
+		container.stop(runnable2);
+		runnable2.waitForCompletion();
+	}
+
+	private DefaultMessageListenerContainer createRunningContainer() {
+		DefaultMessageListenerContainer container = createContainer(createSuccessfulConnectionFactory());
+		container.afterPropertiesSet();
+		container.start();
+		return container;
+	}
+
+	private DefaultMessageListenerContainer createContainer(ConnectionFactory connectionFactory) {
 
 		Destination destination = new Destination() {};
 
@@ -96,9 +119,7 @@ private DefaultMessageListenerContainer createContainer(BackOff backOff, Connect
 		container.setConnectionFactory(connectionFactory);
 		container.setCacheLevel(DefaultMessageListenerContainer.CACHE_NONE);
 		container.setDestination(destination);
-		container.setBackOff(backOff);
 		return container;
-
 	}
 
 	private ConnectionFactory createFailingContainerFactory() {
@@ -141,4 +162,30 @@ public Object answer(InvocationOnMock invocation) throws Throwable {
 		}
 	}
 
+	private ConnectionFactory createSuccessfulConnectionFactory() {
+		try {
+			ConnectionFactory connectionFactory = mock(ConnectionFactory.class);
+			given(connectionFactory.createConnection()).willReturn(mock(Connection.class));
+			return connectionFactory;
+		}
+		catch (JMSException e) {
+			throw new IllegalStateException(); // never happen
+		}
+	}
+
+	private static class TestRunnable implements Runnable {
+		private final CountDownLatch countDownLatch = new CountDownLatch(1);
+
+		@Override
+		public void run() {
+			this.countDownLatch.countDown();
+		}
+
+		public void waitForCompletion() throws InterruptedException {
+			this.countDownLatch.await(2, TimeUnit.SECONDS);
+			assertEquals("callback was not invoked", 0, this.countDownLatch.getCount());
+		}
+
+	}
+
 }