I need to mock a RabbitMQ in my unit Test

Question

I am using a RabbitMQ in my project.

I have in my consumer the code of the client part of rabbitMQ and the connection need a tls1.1 to connect with the real MQ.

Answer 1

So here is how i did it, some stuffs might be here and there in process of hiding the necessary class implementation details, but you would get a hint! :)

• assumption for unit test:
  • RMQ is working fine and data send to it would be pushed in queue
  • Only thing to be tested is if the data generated is correct or not
  • and whether the call to RMQs send() is happening or not!

---

 public class SomeClassTest {
        private Config config;
        private RmqConfig rmqConfig;
        private static final ObjectMapper mapper = new ObjectMapper();
        private JasperServerClient jasperServerClient;
    //    @Mock
        @InjectMocks
        private RabbitMQProducer rabbitMQProducer;
        private Connection phoenixConnection;
        private String targetNotificationMessage;
        SomeClass someClassObject;

        @Before
        public void setUp() {

            // Mock basic stuffs
            config = mock(Config.class);
            Connection = mock(Connection.class);
            rabbitMQProducer = mock(RabbitMQProducer.class); // Imp


            jasperServerClient = mock(JasperServerClient.class);

            rmqConfig = RmqConfig.builder()
                    .host("localhost")
                    .port(5672)
                    .userName("guest")
                    .password("guest")
                    .queueName("somequeue_name")
                    .prefetch(1)
                    .build();
            final String randomMessage = "This is a waste message";
            Message mockMsg = Message.forSending(randomMessage.getBytes(), null, rmqConfig.getQueueName(), rmqConfig.getQueueName(), "text/plain", "UTF-8", true); // prepare a mock message


            // Prepare service configs
            ConnectionConfig connectionConfig = RmqConfigUtil.getConfig(rmqConfig);
            ProducerConfig producerConfig = new ProducerConfigBuilder()
                    .exchange(rmqConfig.getQueueName())
                    .contentType("text/pain")
                    .contentEncoding("UTF-8")
                    .connection(connectionConfig).build();
            rabbitMQProducer.open(croducerConfig.asMap());

            // build the major stuff where the code resides
            someClassObject =  SomeClass.builder()
                    .phoenixConnection(phoenixConnection)
                    .userExchangeName(rmqConfig.getQueueName())
                    .userRabbitMQProducer(rabbitMQProducer)
                    .ftpConfig(config.getFtpConfig())
                    .jasperServerClient(jasperServerClient)
                    .objectMapper(new ObjectMapper())
                    .build();

            MockitoAnnotations.initMocks(this);
        }


        @Test
        public void testNotificationPub() throws Exception {

            // Prepare expected Values
            targetNotificationMessage = <>

            // Reflection -  my target functions were private
            Class cls = Class.forName("com.some.path.to.class");
            Object[] objForGetMessage = {<>, <>};

            Method getNotificationMessage = cls.getDeclaredMethod("private_fn_1", <>.class, <>.class);
            Method pubNotification = cls.getDeclaredMethod("private_fn_2", <>.class, RabbitMQProducer.class, String.class);

            getNotificationMessage.setAccessible(true);
            pubNotification.setAccessible(true);

            // Test Case #1
            final <> notificationMessage = (<>)getNotificationMessage.invoke(someClassObject, objForGetMessage);
            assertEquals(notificationMessage.getMessage(), targetNotificationMessage);

            // Test Case #2 -  this does RMQ call
            Object[] objPubMessage = {notificationMessage, rabbitMQProducer, rmqConfig.getQueueName()};
            final Object publishNotification = pubNotification.invoke(someClassObject, objPubMessage);
            assertEquals(publishNotificationResp, publishNotification); //viola


            //Important, since RabbitMQProducer is mocked, we need to checkup if function call is made to "send" function which send data to RMQ
            verify(rabbitMQProducer,times(1)).send(any());

        }


        @Test
        public void testMockCreation(){
            assertNotNull(rmqConfig);
            assertNotNull(config);
        }