Mockito doAnswer()

Question

Can I somehow use doAnswer() when an exception is thrown?

I'm using this in my integration test to get method invocations and the test in configured the @RabbitListenerTest...

@RunWith(SpringRunner.class)
@SpringBootTest
public class MyIT {

@Autowired
private RabbitTemplate rabbitTemplate;

@Autowired
private MyRabbitListener myRabbitListener;

@Autowired
private RabbitListenerTestHarness harness;

@Test
public void testListener() throws InterruptedException {
  MyRabbitListener myRabbitListener = this.harness.getSpy("event");
  assertNotNull(myRabbitListener);

  final String message = "Test Message";
  LatchCountDownAndCallRealMethodAnswer answer = new LatchCountDownAndCallRealMethodAnswer(1);
  doAnswer(answer).when(myRabbitListener).event(message);

  rabbitTemplate.convertAndSend("exchange", "key", message);

  assertTrue(answer.getLatch().await(20, TimeUnit.SECONDS));
  verify(myRabbitListener).messageReceiver(message);
}

@Configuration
@RabbitListenerTest
public static class Config {
  @Bean
  public MyRabbitListener myRabbitListener(){
    return new MyRabbitListener();
  }
 }
}

It works ok but when I introduce an Exception being thrown, It doesn't i.e

This works

@RabbitListener(id = "event", queues = "queue-name")
  public void event(String message) {
    log.info("received message > " + message);
}

This doesn't

@RabbitListener(id = "event", queues = "queue-name")
  public void event(String message) {
    log.info("received message > " + message);
    throw new ImmediateAcknowledgeAmqpException("Invalid message, " + message);
}

Any help appreciated

Answer 1

The LatchCountDownAndCallRealMethodAnswer is very basic

@Override
public Void answer(InvocationOnMock invocation) throws Throwable {
    invocation.callRealMethod();
    this.latch.countDown();
    return null;
}

You can copy it to a new class and change it to something like

private volatile Exception exeption;

@Override
public Void answer(InvocationOnMock invocation) throws Throwable {
    try {
        invocation.callRealMethod();
    } 
    catch (RuntimeException e) {
        this.exception = e;
        throw e;
    }
    finally {
        this.latch.countDown();
    }
    return null;
}

public Exception getException() {
    return this.exception;
}

then

assertTrue(answer.getLatch().await(20, TimeUnit.SECONDS));
assertThat(answer.getException(), isInstanceOf(ImmediateAcknowledgeAmqpException.class));

Please open a github issue; the framework should support this out-of-the-box.