Mock Component
Testing of distributed and asynchronous processing is notoriously difficult. The Mock, Test and DataSet endpoints work great with the Camel Testing Framework to simplify your unit and integration testing using Enterprise Integration Patterns and Camel's large range of Components together with the powerful Bean Integration.
The Mock component provides a powerful declarative testing mechanism, which is similar to jMock in that it allows declarative expectations to be created on any Mock endpoint before a test begins. Then the test is run, which typically fires messages to one or more endpoints, and finally the expectations can be asserted in a test case to ensure the system worked as expected.
This allows you to test various things like:
- The correct number of messages are received on each endpoint,
- The correct payloads are received, in the right order,
- Messages arrive on an endpoint in order, using some _expression_ to create an order testing function,
- Messages arrive match some kind of Predicate such as that specific headers have certain values, or that parts of the messages match some predicate, such as by evaluating an XPath or XQuery _expression_.
Note that there is also the Test endpoint which is a Mock endpoint, but which uses a second endpoint to provide the list of expected message bodies and automatically sets up the Mock endpoint assertions. In other words, it's a Mock endpoint that automatically sets up its assertions from some sample messages in a File or database, for example.
URI format
Where someName can be any string that uniquely identifies the endpoint.
You can append query options to the URI in the following format, ?option=value&option=value&...
Options
Option |
Default |
Description |
reportGroup |
null |
A size to use a throughput logger for reporting |
Simple Example
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.resolveEndpoint("mock:foo", MockEndpoint.class);
resultEndpoint.expectedMessageCount(2);
...
resultEndpoint.assertIsSatisfied();
You typically always call the assertIsSatisfied() 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.
Using assertPeriod
Available as of Camel 2.7
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.resolveEndpoint("mock:foo", MockEndpoint.class);
resultEndpoint.setAssertPeriod(5000);
resultEndpoint.expectedMessageCount(2);
...
resultEndpoint.assertIsSatisfied();
Setting expectations
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");
Adding expectations to specific messages
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.
Mocking existing endpoints
Available as of Camel 2.7
Camel now allows you to automatic mock existing endpoints in your Camel routes.
![]() | How it works Important: The endpoints are still in action, what happens is that a Mock endpoint is injected and receives the message first, it then delegate the message to the target endpoint. You can view this as a kind of intercept and delegate or endpoint listener. |
Suppose you have the given route below:
@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"));
}
};
}
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:
public void testAdvisedMockEndpoints() throws Exception {
context.getRouteDefinitions().get(0).adviceWith(context, new AdviceWithRouteBuilder() {
@Override
public void configure() throws Exception {
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();
assertNotNull(context.hasEndpoint("direct:start"));
assertNotNull(context.hasEndpoint("direct:foo"));
assertNotNull(context.hasEndpoint("log:foo"));
assertNotNull(context.hasEndpoint("mock:result"));
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:
![]() | Mocked endpoints are without parameters Endpoints which are mocked will have their parameters stripped off. For example the endpoint "log:foo?showAll=true" will be mocked to the following endpoint "mock:log:foo". Notice the parameters has been removed. |
Its also possible to only mock certain endpoints using a pattern. For example to mock all log endpoints you do as shown:
public void testAdvisedMockEndpointsWithPattern() throws Exception {
context.getRouteDefinitions().get(0).adviceWith(context, new AdviceWithRouteBuilder() {
@Override
public void configure() throws Exception {
mockEndpoints("log*");
}
});
getMockEndpoint("mock:log:foo").expectedBodiesReceived("Bye World");
getMockEndpoint("mock:result").expectedBodiesReceived("Bye World");
template.sendBody("direct:start", "Hello World");
assertMockEndpointsSatisfied();
assertNotNull(context.hasEndpoint("direct:start"));
assertNotNull(context.hasEndpoint("direct:foo"));
assertNotNull(context.hasEndpoint("log:foo"));
assertNotNull(context.hasEndpoint("mock:result"));
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.
![]() | Mind that mocking endpoints causes the messages to be copied when they arrive on the mock.
That means Camel will use more memory. This may not be suitable when you send in a lot of messages. |
Mocking existing endpoints using the camel-test component
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.
public class IsMockEndpointsJUnit4Test extends CamelTestSupport {
@Override
public String isMockEndpoints() {
return "*";
}
@Test
public void testMockAllEndpoints() throws Exception {
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();
assertNotNull(context.hasEndpoint("direct:start"));
assertNotNull(context.hasEndpoint("direct:foo"));
assertNotNull(context.hasEndpoint("log:foo"));
assertNotNull(context.hasEndpoint("mock:result"));
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"));
}
};
}
}
Mocking existing endpoints with XML DSL
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:
<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:
<import resource="camel-route.xml"/>
<bean id="mockAllEndpoints" class="org.apache.camel.impl.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>
Testing with arrival times
Available as of Camel 2.7
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();
![]() | time units In the example above we use seconds as the time unit, but Camel offers milliseconds, and minutes as well. |
See Also