title: Mockbean would not throw an error when called inside the test subject class
body: <p>Seems that the mockbean which returns void is not throwing an error when being called inside the test subject. I am able to call it outside and it would throw an error. Is there something wrong with how I am using it?</p>
  
  <pre><code>//some imports ...
  @RunWith(SpringRunner.class)
  @SpringBootTest(classes={ MessagingController.class })
  public class MessagingControllerTest {
      @Autowired
      private MessagingController controller;
  
      @MockBean
      private RabbitMessagingTemplate rabbitMessagingTemplate;
  
      @Test
      public void testPublishMessageConversionException() {
          //given:
          Message message = new Message(null, null, null);
  
          //when:
          doThrow(MessageConversionException.class).when(rabbitMessagingTemplate).convertAndSend(any());
          ResponseEntity&lt;?&gt; response = controller.publish(message);
          // rabbitMessagingTemplate.convertAndSend() // this throws the error
          //then:
          assertThat(response).isNotNull();
          assertThat(response.getStatusCode()).isEqualTo(HttpStatus.BAD_REQUEST);
  
          verify(rabbitMessagingTemplate).convertAndSend(message.getExchange(), message.getRoutingKey(), message.getPayload());
      }
  
   ...
  
  }
  </code></pre>