Chapter 37. Mock

mock:someName[?options]

Where someName can be any string that uniquely identifies the endpoint.

Camel components are configured on two separate levels:

The Mock component supports 4 options, which are listed below.

The Mock endpoint is configured using URI syntax:

mock:name

with the following path and query parameters:

Here’s a simple example of Mock endpoint in use. First, the endpoint is resolved on the context. Then we set an expectation, and then, after the test has run, we assert that our expectations have been met:

MockEndpoint resultEndpoint = context.getEndpoint("mock:foo", MockEndpoint.class);

// set expectations
resultEndpoint.expectedMessageCount(2);

// send some messages

// now lets assert that the mock:foo endpoint received 2 messages
resultEndpoint.assertIsSatisfied();

You typically always call the method to test that the expectations were met after running a test.

Camel will by default wait 10 seconds when the assertIsSatisfied() is invoked. This can be configured by setting the setResultWaitTime(millis) method.

When the assertion is satisfied then Camel will stop waiting and continue from the assertIsSatisfied method. That means if a new message arrives on the mock endpoint, just a bit later, that arrival will not affect the outcome of the assertion. Suppose you do want to test that no new messages arrives after a period thereafter, then you can do that by setting the setAssertPeriod method, for example:

MockEndpoint resultEndpoint = context.getEndpoint("mock:foo", MockEndpoint.class);
resultEndpoint.setAssertPeriod(5000);
resultEndpoint.expectedMessageCount(2);

// send some messages

// now lets assert that the mock:foo endpoint received 2 messages
resultEndpoint.assertIsSatisfied();

You can see from the Javadoc of MockEndpoint the various helper methods you can use to set expectations. The main methods are as follows:

Here’s another example:

resultEndpoint.expectedBodiesReceived("firstMessageBody", "secondMessageBody", "thirdMessageBody");

In addition, you can use the message(int messageIndex) method to add assertions about a specific message that is received.

For example, to add expectations of the headers or body of the first message (using zero-based indexing like java.util.List), you can use the following code:

resultEndpoint.message(0).header("foo").isEqualTo("bar");

There are some examples of the Mock endpoint in use in the camel-core processor tests.

Camel now allows you to automatically mock existing endpoints in your Camel routes.

Suppose you have the given route below:

Route

    @Override
    protected RouteBuilder createRouteBuilder() throws Exception {
        return new RouteBuilder() {
            @Override
            public void configure() throws Exception {
                from("direct:start").routeId("start")
                        .to("direct:foo").to("log:foo").to("mock:result");

                from("direct:foo").routeId("foo")
                        .transform(constant("Bye World"));
            }
        };
    }

You can then use the adviceWith feature in Camel to mock all the endpoints in a given route from your unit test, as shown below:

adviceWith mocking all endpoints

    @Test
    public void testAdvisedMockEndpoints() throws Exception {
        // advice the start route using the inlined AdviceWith lambda style route builder
        // which has extended capabilities than the regular route builder
        AdviceWith.adviceWith(context, "start", a ->
        // mock all endpoints
        a.mockEndpoints());

        getMockEndpoint("mock:direct:start").expectedBodiesReceived("Hello World");
        getMockEndpoint("mock:direct:foo").expectedBodiesReceived("Hello World");
        getMockEndpoint("mock:log:foo").expectedBodiesReceived("Bye World");
        getMockEndpoint("mock:result").expectedBodiesReceived("Bye World");

        template.sendBody("direct:start", "Hello World");

        assertMockEndpointsSatisfied();

        // additional test to ensure correct endpoints in registry
        assertNotNull(context.hasEndpoint("direct:start"));
        assertNotNull(context.hasEndpoint("direct:foo"));
        assertNotNull(context.hasEndpoint("log:foo"));
        assertNotNull(context.hasEndpoint("mock:result"));
        // all the endpoints was mocked
        assertNotNull(context.hasEndpoint("mock:direct:start"));
        assertNotNull(context.hasEndpoint("mock:direct:foo"));
        assertNotNull(context.hasEndpoint("mock:log:foo"));
    }

Notice that the mock endpoints is given the URI mock:<endpoint>, for example mock:direct:foo. Camel logs at INFO level the endpoints being mocked:

INFO  Adviced endpoint [direct://foo] with mock endpoint [mock:direct:foo]

Its also possible to only mock certain endpoints using a pattern. For example to mock all log endpoints you do as shown:

adviceWith mocking only log endpoints using a pattern

    @Test
    public void testAdvisedMockEndpointsWithPattern() throws Exception {
        // advice the start route using the inlined AdviceWith lambda style route builder
        // which has extended capabilities than the regular route builder
        AdviceWith.adviceWith(context, "start", a ->
        // mock only log endpoints
        a.mockEndpoints("log*"));

        // now we can refer to log:foo as a mock and set our expectations
        getMockEndpoint("mock:log:foo").expectedBodiesReceived("Bye World");

        getMockEndpoint("mock:result").expectedBodiesReceived("Bye World");

        template.sendBody("direct:start", "Hello World");

        assertMockEndpointsSatisfied();

        // additional test to ensure correct endpoints in registry
        assertNotNull(context.hasEndpoint("direct:start"));
        assertNotNull(context.hasEndpoint("direct:foo"));
        assertNotNull(context.hasEndpoint("log:foo"));
        assertNotNull(context.hasEndpoint("mock:result"));
        // only the log:foo endpoint was mocked
        assertNotNull(context.hasEndpoint("mock:log:foo"));
        assertNull(context.hasEndpoint("mock:direct:start"));
        assertNull(context.hasEndpoint("mock:direct:foo"));
    }

The pattern supported can be a wildcard or a regular expression. See more details about this at Intercept as its the same matching function used by Camel.

Instead of using the adviceWith to instruct Camel to mock endpoints, you can easily enable this behavior when using the camel-test Test Kit.

The same route can be tested as follows. Notice that we return "*" from the isMockEndpoints method, which tells Camel to mock all endpoints.

If you only want to mock all log endpoints you can return "log*" instead.

isMockEndpoints using camel-test kit

public class IsMockEndpointsJUnit4Test extends CamelTestSupport {

    @Override
    public String isMockEndpoints() {
        // override this method and return the pattern for which endpoints to mock.
        // use * to indicate all
        return "*";
    }

    @Test
    public void testMockAllEndpoints() throws Exception {
        // notice we have automatic mocked all endpoints and the name of the endpoints is "mock:uri"
        getMockEndpoint("mock:direct:start").expectedBodiesReceived("Hello World");
        getMockEndpoint("mock:direct:foo").expectedBodiesReceived("Hello World");
        getMockEndpoint("mock:log:foo").expectedBodiesReceived("Bye World");
        getMockEndpoint("mock:result").expectedBodiesReceived("Bye World");

        template.sendBody("direct:start", "Hello World");

        assertMockEndpointsSatisfied();

        // additional test to ensure correct endpoints in registry
        assertNotNull(context.hasEndpoint("direct:start"));
        assertNotNull(context.hasEndpoint("direct:foo"));
        assertNotNull(context.hasEndpoint("log:foo"));
        assertNotNull(context.hasEndpoint("mock:result"));
        // all the endpoints was mocked
        assertNotNull(context.hasEndpoint("mock:direct:start"));
        assertNotNull(context.hasEndpoint("mock:direct:foo"));
        assertNotNull(context.hasEndpoint("mock:log:foo"));
    }

    @Override
    protected RouteBuilder createRouteBuilder() throws Exception {
        return new RouteBuilder() {
            @Override
            public void configure() throws Exception {
                from("direct:start").to("direct:foo").to("log:foo").to("mock:result");

                from("direct:foo").transform(constant("Bye World"));
            }
        };
    }
}

If you do not use the camel-test component for unit testing (as shown above) you can use a different approach when using XML files for routes.
The solution is to create a new XML file used by the unit test and then include the intended XML file which has the route you want to test.

Suppose we have the route in the camel-route.xml file:

    <!-- this camel route is in the camel-route.xml file -->
    <camelContext xmlns="http://camel.apache.org/schema/spring">

        <route>
            <from uri="direct:start"/>
            <to uri="direct:foo"/>
            <to uri="log:foo"/>
            <to uri="mock:result"/>
        </route>

        <route>
            <from uri="direct:foo"/>
            <transform>
                <constant>Bye World</constant>
            </transform>
        </route>

    </camelContext>

Then we create a new XML file as follows, where we include the camel-route.xml file and define a spring bean with the class org.apache.camel.impl.InterceptSendToMockEndpointStrategy which tells Camel to mock all endpoints:

    <!-- the Camel route is defined in another XML file -->
    <import resource="camel-route.xml"/>

    <!-- bean which enables mocking all endpoints -->
    <bean id="mockAllEndpoints" class="org.apache.camel.component.mock.InterceptSendToMockEndpointStrategy"/>

Then in your unit test you load the new XML file (test-camel-route.xml) instead of camel-route.xml.

To only mock all Log endpoints you can define the pattern in the constructor for the bean:

<bean id="mockAllEndpoints" class="org.apache.camel.impl.InterceptSendToMockEndpointStrategy">
    <constructor-arg index="0" value="log*"/>
</bean>

Sometimes you want to easily mock and skip sending to a certain endpoints. So the message is detoured and send to the mock endpoint only. You can now use the mockEndpointsAndSkip method using AdviceWith. The example below will skip sending to the two endpoints "direct:foo", and "direct:bar".

adviceWith mock and skip sending to endpoints

    @Test
    public void testAdvisedMockEndpointsWithSkip() throws Exception {
        // advice the first route using the inlined AdviceWith route builder
        // which has extended capabilities than the regular route builder
        AdviceWith.adviceWith(context.getRouteDefinitions().get(0), context, new AdviceWithRouteBuilder() {
            @Override
            public void configure() throws Exception {
                // mock sending to direct:foo and direct:bar and skip send to it
                mockEndpointsAndSkip("direct:foo", "direct:bar");
            }
        });

        getMockEndpoint("mock:result").expectedBodiesReceived("Hello World");
        getMockEndpoint("mock:direct:foo").expectedMessageCount(1);
        getMockEndpoint("mock:direct:bar").expectedMessageCount(1);

        template.sendBody("direct:start", "Hello World");

        assertMockEndpointsSatisfied();

        // the message was not send to the direct:foo route and thus not sent to
        // the seda endpoint
        SedaEndpoint seda = context.getEndpoint("seda:foo", SedaEndpoint.class);
        assertEquals(0, seda.getCurrentQueueSize());
    }

The same example using the Test Kit

isMockEndpointsAndSkip using camel-test kit

public class IsMockEndpointsAndSkipJUnit4Test extends CamelTestSupport {

    @Override
    public String isMockEndpointsAndSkip() {
        // override this method and return the pattern for which endpoints to mock,
        // and skip sending to the original endpoint.
        return "direct:foo";
    }

    @Test
    public void testMockEndpointAndSkip() throws Exception {
        // notice we have automatic mocked the direct:foo endpoints and the name of the endpoints is "mock:uri"
        getMockEndpoint("mock:result").expectedBodiesReceived("Hello World");
        getMockEndpoint("mock:direct:foo").expectedMessageCount(1);

        template.sendBody("direct:start", "Hello World");

        assertMockEndpointsSatisfied();

        // the message was not send to the direct:foo route and thus not sent to the seda endpoint
        SedaEndpoint seda = context.getEndpoint("seda:foo", SedaEndpoint.class);
        assertEquals(0, seda.getCurrentQueueSize());
    }

    @Override
    protected RouteBuilder createRouteBuilder() throws Exception {
        return new RouteBuilder() {
            @Override
            public void configure() throws Exception {
                from("direct:start").to("direct:foo").to("mock:result");

                from("direct:foo").transform(constant("Bye World")).to("seda:foo");
            }
        };
    }
}

The Mock endpoints will by default keep a copy of every Exchange that it received. So if you test with a lot of messages, then it will consume memory.
We have introduced two options retainFirst and retainLast that can be used to specify to only keep N’th of the first and/or last Exchanges.

For example in the code below, we only want to retain a copy of the first 5 and last 5 Exchanges the mock receives.

  MockEndpoint mock = getMockEndpoint("mock:data");
  mock.setRetainFirst(5);
  mock.setRetainLast(5);
  mock.expectedMessageCount(2000);

  mock.assertIsSatisfied();

Using this has some limitations. The getExchanges() and getReceivedExchanges() methods on the MockEndpoint will return only the retained copies of the Exchanges. So in the example above, the list will contain 10 Exchanges; the first five, and the last five.
The retainFirst and retainLast options also have limitations on which expectation methods you can use. For example the expectedXXX methods that work on message bodies, headers, etc. will only operate on the retained messages. In the example above they can test only the expectations on the 10 retained messages.

The Mock endpoint stores the arrival time of the message as a property on the Exchange

Date time = exchange.getProperty(Exchange.RECEIVED_TIMESTAMP, Date.class);

You can use this information to know when the message arrived on the mock. But it also provides foundation to know the time interval between the previous and next message arrived on the mock. You can use this to set expectations using the arrives DSL on the Mock endpoint.

For example to say that the first message should arrive between 0-2 seconds before the next you can do:

mock.message(0).arrives().noLaterThan(2).seconds().beforeNext();

You can also define this as that 2nd message (0 index based) should arrive no later than 0-2 seconds after the previous:

mock.message(1).arrives().noLaterThan(2).seconds().afterPrevious();

You can also use between to set a lower bound. For example suppose that it should be between 1-4 seconds:

mock.message(1).arrives().between(1, 4).seconds().afterPrevious();

You can also set the expectation on all messages, for example to say that the gap between them should be at most 1 second:

mock.allMessages().arrives().noLaterThan(1).seconds().beforeNext();

When using mock with Spring Boot make sure to use the following Maven dependency to have support for auto configuration:

<dependency>
  <groupId>org.apache.camel.springboot</groupId>
  <artifactId>camel-mock-starter</artifactId>
</dependency>

The component supports 5 options, which are listed below.