Testing Support

Writing integration for asynchronous applications is necessarily more complex than testing simpler applications. This is made more complex when abstractions such as the @RabbitListener annotations come into the picture. The question is how to verify that, after sending a message, the listener received the message as expected.

The framework itself has many unit and integration tests. Some using mocks while, others use integration testing with a live RabbitMQ broker. You can consult those tests for some ideas for testing scenarios.

Spring AMQP version 1.6 introduced the spring-rabbit-test jar, which provides support for testing some of these more complex scenarios. It is anticipated that this project will expand over time, but we need community feedback to make suggestions for the features needed to help with testing. Please use JIRA or GitHub Issues to provide such feedback.

@SpringRabbitTest

Use this annotation to add infrastructure beans to the Spring test ApplicationContext. This is not necessary when using, for example @SpringBootTest since Spring Boot’s auto configuration will add the beans.

Beans that are registered are:

CachingConnectionFactory (autoConnectionFactory). If @RabbitEnabled is present, its connection factory is used.
RabbitTemplate (autoRabbitTemplate)
RabbitAdmin (autoRabbitAdmin)
RabbitListenerContainerFactory (autoContainerFactory)

In addition, the beans associated with @EnableRabbit (to support @RabbitListener) are added.

Junit5 example

@SpringJUnitConfig
@SpringRabbitTest
public class MyRabbitTests {

	@Autowired
	private RabbitTemplate template;

	@Autowired
	private RabbitAdmin admin;

	@Autowired
	private RabbitListenerEndpointRegistry registry;

	@Test
	void test() {
        ...
	}

	@Configuration
	public static class Config {

        ...

	}

}

With JUnit4, replace @SpringJUnitConfig with @RunWith(SpringRunnner.class).

Mockito `Answer<?>` Implementations

There are currently two Answer<?> implementations to help with testing.

The first, LatchCountDownAndCallRealMethodAnswer, provides an Answer<Void> that returns null and counts down a latch. The following example shows how to use LatchCountDownAndCallRealMethodAnswer:

LatchCountDownAndCallRealMethodAnswer answer = this.harness.getLatchAnswerFor("myListener", 2);
doAnswer(answer)
    .when(listener).foo(anyString(), anyString());

...

assertThat(answer.await(10)).isTrue();

The second, LambdaAnswer<T> provides a mechanism to optionally call the real method and provides an opportunity to return a custom result, based on the InvocationOnMock and the result (if any).

Consider the following POJO:

public class Thing {

    public String thing(String thing) {
        return thing.toUpperCase();
    }

}

The following class tests the Thing POJO:

Thing thing = spy(new Thing());

doAnswer(new LambdaAnswer<String>(true, (i, r) -> r + r))
    .when(thing).thing(anyString());
assertEquals("THINGTHING", thing.thing("thing"));

doAnswer(new LambdaAnswer<String>(true, (i, r) -> r + i.getArguments()[0]))
    .when(thing).thing(anyString());
assertEquals("THINGthing", thing.thing("thing"));

doAnswer(new LambdaAnswer<String>(false, (i, r) ->
    "" + i.getArguments()[0] + i.getArguments()[0])).when(thing).thing(anyString());
assertEquals("thingthing", thing.thing("thing"));

Starting with version 2.2.3, the answers capture any exceptions thrown by the method under test. Use answer.getExceptions() to get a reference to them.

When used in conjunction with the @RabbitListenerTest and RabbitListenerTestHarness use harness.getLambdaAnswerFor("listenerId", true, …) to get a properly constructed answer for the listener.

`@RabbitListenerTest` and `RabbitListenerTestHarness`

Annotating one of your @Configuration classes with @RabbitListenerTest causes the framework to replace the standard RabbitListenerAnnotationBeanPostProcessor with a subclass called RabbitListenerTestHarness (it also enables @RabbitListener detection through @EnableRabbit).

The RabbitListenerTestHarness enhances the listener in two ways. First, it wraps the listener in a Mockito Spy, enabling normal Mockito stubbing and verification operations. It can also add an Advice to the listener, enabling access to the arguments, result, and any exceptions that are thrown. You can control which (or both) of these are enabled with attributes on the @RabbitListenerTest. The latter is provided for access to lower-level data about the invocation. It also supports blocking the test thread until the async listener is called.

final @RabbitListener methods cannot be spied or advised. Also, only listeners with an id attribute can be spied or advised.

Consider some examples.

The following example uses spy:

@Configuration
@RabbitListenerTest
public class Config {

    @Bean
    public Listener listener() {
        return new Listener();
    }

    ...

}

public class Listener {

    @RabbitListener(id="foo", queues="#{queue1.name}")
    public String foo(String foo) {
        return foo.toUpperCase();
    }

    @RabbitListener(id="bar", queues="#{queue2.name}")
    public void foo(@Payload String foo, @Header("amqp_receivedRoutingKey") String rk) {
        ...
    }

}

public class MyTests {

    @Autowired
    private RabbitListenerTestHarness harness; (1)

    @Test
    public void testTwoWay() throws Exception {
        assertEquals("FOO", this.rabbitTemplate.convertSendAndReceive(this.queue1.getName(), "foo"));

        Listener listener = this.harness.getSpy("foo"); (2)
        assertNotNull(listener);
        verify(listener).foo("foo");
    }

    @Test
    public void testOneWay() throws Exception {
        Listener listener = this.harness.getSpy("bar");
        assertNotNull(listener);

        LatchCountDownAndCallRealMethodAnswer answer = this.harness.getLatchAnswerFor("bar", 2); (3)
        doAnswer(answer).when(listener).foo(anyString(), anyString()); (4)

        this.rabbitTemplate.convertAndSend(this.queue2.getName(), "bar");
        this.rabbitTemplate.convertAndSend(this.queue2.getName(), "baz");

        assertTrue(answer.await(10));
        verify(listener).foo("bar", this.queue2.getName());
        verify(listener).foo("baz", this.queue2.getName());
    }

}

1	Inject the harness into the test case so we can get access to the spy.
2	Get a reference to the spy so we can verify it was invoked as expected. Since this is a send and receive operation, there is no need to suspend the test thread because it was already suspended in the `RabbitTemplate` waiting for the reply.
3	In this case, we’re only using a send operation so we need a latch to wait for the asynchronous call to the listener on the container thread. We use one of the Answer<?> implementations to help with that. IMPORTANT: Due to the way the listener is spied, it is important to use `harness.getLatchAnswerFor()` to get a properly configured answer for the spy.
4	Configure the spy to invoke the `Answer`.

The following example uses the capture advice:

@Configuration
@ComponentScan
@RabbitListenerTest(spy = false, capture = true)
public class Config {

}

@Service
public class Listener {

    private boolean failed;

    @RabbitListener(id="foo", queues="#{queue1.name}")
    public String foo(String foo) {
        return foo.toUpperCase();
    }

    @RabbitListener(id="bar", queues="#{queue2.name}")
    public void foo(@Payload String foo, @Header("amqp_receivedRoutingKey") String rk) {
        if (!failed && foo.equals("ex")) {
            failed = true;
            throw new RuntimeException(foo);
        }
        failed = false;
    }

}

public class MyTests {

    @Autowired
    private RabbitListenerTestHarness harness; (1)

    @Test
    public void testTwoWay() throws Exception {
        assertEquals("FOO", this.rabbitTemplate.convertSendAndReceive(this.queue1.getName(), "foo"));

        InvocationData invocationData =
            this.harness.getNextInvocationDataFor("foo", 0, TimeUnit.SECONDS); (2)
        assertThat(invocationData.getArguments()[0], equalTo("foo"));     (3)
        assertThat((String) invocationData.getResult(), equalTo("FOO"));
    }

    @Test
    public void testOneWay() throws Exception {
        this.rabbitTemplate.convertAndSend(this.queue2.getName(), "bar");
        this.rabbitTemplate.convertAndSend(this.queue2.getName(), "baz");
        this.rabbitTemplate.convertAndSend(this.queue2.getName(), "ex");

        InvocationData invocationData =
            this.harness.getNextInvocationDataFor("bar", 10, TimeUnit.SECONDS); (4)
        Object[] args = invocationData.getArguments();
        assertThat((String) args[0], equalTo("bar"));
        assertThat((String) args[1], equalTo(queue2.getName()));

        invocationData = this.harness.getNextInvocationDataFor("bar", 10, TimeUnit.SECONDS);
        args = invocationData.getArguments();
        assertThat((String) args[0], equalTo("baz"));

        invocationData = this.harness.getNextInvocationDataFor("bar", 10, TimeUnit.SECONDS);
        args = invocationData.getArguments();
        assertThat((String) args[0], equalTo("ex"));
        assertEquals("ex", invocationData.getThrowable().getMessage()); (5)
    }

}

1	Inject the harness into the test case so we can get access to the spy.
2	Use `harness.getNextInvocationDataFor()` to retrieve the invocation data - in this case since it was a request/reply scenario there is no need to wait for any time because the test thread was suspended in the `RabbitTemplate` waiting for the result.
3	We can then verify that the argument and result was as expected.
4	This time we need some time to wait for the data, since it’s an async operation on the container thread and we need to suspend the test thread.
5	When the listener throws an exception, it is available in the `throwable` property of the invocation data.

When using custom Answer<?> s with the harness, in order to operate properly, such answers should subclass ForwardsInvocation and get the actual listener (not the spy) from the harness (getDelegate("myListener")) and call super.answer(invocation). See the provided Mockito Answer<?> Implementations source code for examples.

Using `TestRabbitTemplate`

The TestRabbitTemplate is provided to perform some basic integration testing without the need for a broker. When you add it as a @Bean in your test case, it discovers all the listener containers in the context, whether declared as @Bean or <bean/> or using the @RabbitListener annotation. It currently only supports routing by queue name. The template extracts the message listener from the container and invokes it directly on the test thread. Request-reply messaging (sendAndReceive methods) is supported for listeners that return replies.

The following test case uses the template:

@RunWith(SpringRunner.class)
public class TestRabbitTemplateTests {

    @Autowired
    private TestRabbitTemplate template;

    @Autowired
    private Config config;

    @Test
    public void testSimpleSends() {
        this.template.convertAndSend("foo", "hello1");
        assertThat(this.config.fooIn, equalTo("foo:hello1"));
        this.template.convertAndSend("bar", "hello2");
        assertThat(this.config.barIn, equalTo("bar:hello2"));
        assertThat(this.config.smlc1In, equalTo("smlc1:"));
        this.template.convertAndSend("foo", "hello3");
        assertThat(this.config.fooIn, equalTo("foo:hello1"));
        this.template.convertAndSend("bar", "hello4");
        assertThat(this.config.barIn, equalTo("bar:hello2"));
        assertThat(this.config.smlc1In, equalTo("smlc1:hello3hello4"));

        this.template.setBroadcast(true);
        this.template.convertAndSend("foo", "hello5");
        assertThat(this.config.fooIn, equalTo("foo:hello1foo:hello5"));
        this.template.convertAndSend("bar", "hello6");
        assertThat(this.config.barIn, equalTo("bar:hello2bar:hello6"));
        assertThat(this.config.smlc1In, equalTo("smlc1:hello3hello4hello5hello6"));
    }

    @Test
    public void testSendAndReceive() {
        assertThat(this.template.convertSendAndReceive("baz", "hello"), equalTo("baz:hello"));
    }

    @Configuration
    @EnableRabbit
    public static class Config {

        public String fooIn = "";

        public String barIn = "";

        public String smlc1In = "smlc1:";

        @Bean
        public TestRabbitTemplate template() throws IOException {
            return new TestRabbitTemplate(connectionFactory());
        }

        @Bean
        public ConnectionFactory connectionFactory() throws IOException {
            ConnectionFactory factory = mock(ConnectionFactory.class);
            Connection connection = mock(Connection.class);
            Channel channel = mock(Channel.class);
            willReturn(connection).given(factory).createConnection();
            willReturn(channel).given(connection).createChannel(anyBoolean());
            given(channel.isOpen()).willReturn(true);
            return factory;
        }

        @Bean
        public SimpleRabbitListenerContainerFactory rabbitListenerContainerFactory() throws IOException {
            SimpleRabbitListenerContainerFactory factory = new SimpleRabbitListenerContainerFactory();
            factory.setConnectionFactory(connectionFactory());
            return factory;
        }

        @RabbitListener(queues = "foo")
        public void foo(String in) {
            this.fooIn += "foo:" + in;
        }

        @RabbitListener(queues = "bar")
        public void bar(String in) {
            this.barIn += "bar:" + in;
        }

        @RabbitListener(queues = "baz")
        public String baz(String in) {
            return "baz:" + in;
        }

        @Bean
        public SimpleMessageListenerContainer smlc1() throws IOException {
            SimpleMessageListenerContainer container = new SimpleMessageListenerContainer(connectionFactory());
            container.setQueueNames("foo", "bar");
            container.setMessageListener(new MessageListenerAdapter(new Object() {

                public void handleMessage(String in) {
                    smlc1In += in;
                }

            }));
            return container;
        }

    }

}

JUnit4 `@Rules`

Spring AMQP version 1.7 and later provide an additional jar called spring-rabbit-junit. This jar contains a couple of utility @Rule instances for use when running JUnit4 tests. See JUnit5 Conditions for JUnit5 testing.

Using `BrokerRunning`

BrokerRunning provides a mechanism to let tests succeed when a broker is not running (on localhost, by default).

It also has utility methods to initialize and empty queues and delete queues and exchanges.

The following example shows its usage:

@ClassRule
public static BrokerRunning brokerRunning = BrokerRunning.isRunningWithEmptyQueues("foo", "bar");

@AfterClass
public static void tearDown() {
    brokerRunning.removeTestQueues("some.other.queue.too") // removes foo, bar as well
}

There are several isRunning… static methods, such as isBrokerAndManagementRunning(), which verifies the broker has the management plugin enabled.

Configuring the Rule

There are times when you want tests to fail if there is no broker, such as a nightly CI build. To disable the rule at runtime, set an environment variable called RABBITMQ_SERVER_REQUIRED to true.

You can override the broker properties, such as hostname with either setters or environment variables:

The following example shows how to override properties with setters:

@ClassRule
public static BrokerRunning brokerRunning = BrokerRunning.isRunningWithEmptyQueues("foo", "bar");

static {
    brokerRunning.setHostName("10.0.0.1")
}

@AfterClass
public static void tearDown() {
    brokerRunning.removeTestQueues("some.other.queue.too") // removes foo, bar as well
}

You can also override properties by setting the following environment variables:

public static final String BROKER_ADMIN_URI = "RABBITMQ_TEST_ADMIN_URI";
public static final String BROKER_HOSTNAME = "RABBITMQ_TEST_HOSTNAME";
public static final String BROKER_PORT = "RABBITMQ_TEST_PORT";
public static final String BROKER_USER = "RABBITMQ_TEST_USER";
public static final String BROKER_PW = "RABBITMQ_TEST_PASSWORD";
public static final String BROKER_ADMIN_USER = "RABBITMQ_TEST_ADMIN_USER";
public static final String BROKER_ADMIN_PW = "RABBITMQ_TEST_ADMIN_PASSWORD";

These environment variables override the default settings (localhost:5672 for amqp and localhost:15672/api/ for the management REST API).

Changing the host name affects both the amqp and management REST API connection (unless the admin uri is explicitly set).

BrokerRunning also provides a static method called setEnvironmentVariableOverrides that lets you can pass in a map containing these variables. They override system environment variables. This might be useful if you wish to use different configuration for tests in multiple test suites. IMPORTANT: The method must be called before invoking any of the isRunning() static methods that create the rule instance. Variable values are applied to all instances created after this invocation. Invoke clearEnvironmentVariableOverrides() to reset the rule to use defaults (including any actual environment variables).

In your test cases, you can use the brokerRunning when creating the connection factory; getConnectionFactory() returns the rule’s RabbitMQ ConnectionFactory. The following example shows how to do so:

@Bean
public CachingConnectionFactory rabbitConnectionFactory() {
    return new CachingConnectionFactory(brokerRunning.getConnectionFactory());
}

Using `LongRunningIntegrationTest`

LongRunningIntegrationTest is a rule that disables long running tests. You might want to use this on a developer system but ensure that the rule is disabled on, for example, nightly CI builds.

The following example shows its usage:

@Rule
public LongRunningIntegrationTest longTests = new LongRunningIntegrationTest();

To disable the rule at runtime, set an environment variable called RUN_LONG_INTEGRATION_TESTS to true.

JUnit5 Conditions

Version 2.0.2 introduced support for JUnit5.

Using the `@RabbitAvailable` Annotation

This class-level annotation is similar to the BrokerRunning @Rule discussed in JUnit4 @Rules. It is processed by the RabbitAvailableCondition.

The annotation has three properties:

queues: An array of queues that are declared (and purged) before each test and deleted when all tests are complete.
management: Set this to true if your tests also require the management plugin installed on the broker.
purgeAfterEach: (Since version 2.2) when true (default), the queues will be purged between tests.

It is used to check whether the broker is available and skip the tests if not. As discussed in Configuring the Rule, the environment variable called RABBITMQ_SERVER_REQUIRED, if true, causes the tests to fail fast if there is no broker. You can configure the condition by using environment variables as discussed in Configuring the Rule.

In addition, the RabbitAvailableCondition supports argument resolution for parameterized test constructors and methods. Two argument types are supported:

BrokerRunningSupport: The instance (before 2.2, this was a JUnit 4 BrokerRunning instance)
ConnectionFactory: The BrokerRunningSupport instance’s RabbitMQ connection factory

The following example shows both:

@RabbitAvailable(queues = "rabbitAvailableTests.queue")
public class RabbitAvailableCTORInjectionTests {

    private final ConnectionFactory connectionFactory;

    public RabbitAvailableCTORInjectionTests(BrokerRunningSupport brokerRunning) {
        this.connectionFactory = brokerRunning.getConnectionFactory();
    }

    @Test
    public void test(ConnectionFactory cf) throws Exception {
        assertSame(cf, this.connectionFactory);
        Connection conn = this.connectionFactory.newConnection();
        Channel channel = conn.createChannel();
        DeclareOk declareOk = channel.queueDeclarePassive("rabbitAvailableTests.queue");
        assertEquals(0, declareOk.getConsumerCount());
        channel.close();
        conn.close();
    }

}

The preceding test is in the framework itself and verifies the argument injection and that the condition created the queue properly.

A practical user test might be as follows:

@RabbitAvailable(queues = "rabbitAvailableTests.queue")
public class RabbitAvailableCTORInjectionTests {

    private final CachingConnectionFactory connectionFactory;

    public RabbitAvailableCTORInjectionTests(BrokerRunningSupport brokerRunning) {
        this.connectionFactory =
            new CachingConnectionFactory(brokerRunning.getConnectionFactory());
    }

    @Test
    public void test() throws Exception {
        RabbitTemplate template = new RabbitTemplate(this.connectionFactory);
        ...
    }
}

When you use a Spring annotation application context within a test class, you can get a reference to the condition’s connection factory through a static method called RabbitAvailableCondition.getBrokerRunning().

Starting with version 2.2, getBrokerRunning() returns a BrokerRunningSupport object; previously, the JUnit 4 BrokerRunnning instance was returned. The new class has the same API as BrokerRunning.

The following test comes from the framework and demonstrates the usage:

@RabbitAvailable(queues = {
        RabbitTemplateMPPIntegrationTests.QUEUE,
        RabbitTemplateMPPIntegrationTests.REPLIES })
@SpringJUnitConfig
@DirtiesContext(classMode = ClassMode.AFTER_EACH_TEST_METHOD)
public class RabbitTemplateMPPIntegrationTests {

    public static final String QUEUE = "mpp.tests";

    public static final String REPLIES = "mpp.tests.replies";

    @Autowired
    private RabbitTemplate template;

    @Autowired
    private Config config;

    @Test
    public void test() {

        ...

    }

    @Configuration
    @EnableRabbit
    public static class Config {

        @Bean
        public CachingConnectionFactory cf() {
            return new CachingConnectionFactory(RabbitAvailableCondition
                    .getBrokerRunning()
                    .getConnectionFactory());
        }

        @Bean
        public RabbitTemplate template() {

            ...

        }

        @Bean
        public SimpleRabbitListenerContainerFactory
                            rabbitListenerContainerFactory() {

            ...

        }

        @RabbitListener(queues = QUEUE)
        public byte[] foo(byte[] in) {
            return in;
        }

    }

}

Using the `@LongRunning` Annotation

Similar to the LongRunningIntegrationTest JUnit4 @Rule, this annotation causes tests to be skipped unless an environment variable (or system property) is set to true. The following example shows how to use it:

@RabbitAvailable(queues = SimpleMessageListenerContainerLongTests.QUEUE)
@LongRunning
public class SimpleMessageListenerContainerLongTests {

    public static final String QUEUE = "SimpleMessageListenerContainerLongTests.queue";

...

}

By default, the variable is RUN_LONG_INTEGRATION_TESTS, but you can specify the variable name in the annotation’s value attribute.

Testing Support

@SpringRabbitTest

Mockito Answer<?> Implementations

@RabbitListenerTest and RabbitListenerTestHarness

Using TestRabbitTemplate

JUnit4 @Rules

Using BrokerRunning