As a simple alternative to using Spring Testing or Guice the camel-test module was introduced so you can perform powerful Testing of your Enterprise Integration Patterns easily.
|The camel-test JAR is using JUnit. There is an alternative camel-testng JAR (Camel 2.8 onwards) using the TestNG test framework.|
Adding to your pom.xml
To get started using Camel Test you will need to add an entry to your pom.xml
Available as of Camel 2.8
You might also want to add slf4j and log4j to ensure nice logging messages (and maybe adding a log4j.properties file into your src/test/resources directory).
Writing your test
You firstly need to derive from the class CamelTestSupport (org.apache.camel.test.CamelTestSupport, org.apache.camel.test.junit4.CamelTestSupport, or org.apache.camel.testng.CamelTestSupport for JUnit 3.x, JUnit 4.x, and TestNG, respectively) and typically you will need to override the createRouteBuilder() or createRouteBuilders() method to create routes to be tested.
Here is an example.
Notice how you can use the various Camel binding and injection annotations to inject individual Endpoint objects - particularly the Mock endpoints which are very useful for Testing. Also you can inject producer objects such as ProducerTemplate or some application code interface for sending messages or invoking services.
Features Provided by CamelTestSupport
The various CamelTestSupport classes provide a standard set of behaviors relating to the CamelContext used to host the route(s) under test. The classes provide a number of methods that allow a test to alter the configuration of the CamelContext used. The following table describes the available customization methods and the default behavior of tests that are built from a CamelTestSupport class.
| Method Name || Description || Default Behavior |
| boolean isUseRouteBuilder() || If the route builders from returned from createRouteBuilder() or createRouteBuilders() should be added to the CamelContext used in the test should be started. || Returns true. createRouteBuilder() or createRouteBuilders() are invoked and the CamelContext is started automatically. |
| boolean isUseAdviceWith() |
| If the CamelContext use in the test should be automatically started before test methods are invoked. |
Override when using advice with and return true. This helps in knowing the adviceWith is to be used, and the CamelContext will not be started before the advice with takes place. This delay helps by ensuring the advice with has been property setup before the CamelContext is started.
|Its important to start the CamelContext manually from the unit test after you are done doing all the advice with.|
| Returns false. the CamelContext is started automatically before test methods are invoked. |
| boolean isCreateCamelContextPerClass() |
| See Setup CamelContext once per class, or per every test method. || The CamelContext and routes are recreated for each test method. |
| String isMockEndpoints() || Triggers the auto-mocking of endpoints whose URIs match the provided filter. The default filter is null which disables this feature. Return "*" to match all endpoints. See org.apache.camel.impl.InterceptSendToMockEndpointStrategy for more details on the registration of the mock endpoints. || Disabled |
| boolean isUseDebugger() || If this method returns true, the debugBefore(Exchange exchange, Processor processor, ProcessorDefinition<?> definition, String id, String label) and |
debugAfter(Exchange exchange, Processor processor, ProcessorDefinition<?> definition, String id, String label, long timeTaken) methods are invoked for each processor in the registered routes.
| Disabled. The methods are not invoked during the test. |
| int getShutdownTimeout() || Returns the number of seconds that Camel should wait for graceful shutdown. Useful for decreasing test times when a message is still in flight at the end of the test. || Returns 10 seconds. |
| boolean useJmx() || If JMX should be disabled on the CamelContext used in the test. || JMX is disabled. |
| JndiRegistry createRegistry() |
| Provides a hook for adding objects into the registry. Override this method to bind objects to the registry before test methods are invoked. || An empty registry is initialized. |
| useOverridePropertiesWithPropertiesComponent || Camel 2.10: Allows to add/override properties when Using PropertyPlaceholder in Camel. || null |
| ignoreMissingLocationWithPropertiesComponent || Camel 2.10: Allows to control if Camel should ignore missing locations for properties. || null |
Camel uses a Registry to allow you to configure Component or Endpoint instances or Beans used in your routes. If you are not using Spring or [OSGi] then JNDI is used as the default registry implementation.
So you will also need to create a jndi.properties file in your src/test/resources directory so that there is a default registry available to initialise the CamelContext.
Here is an example jndi.properties file
Dynamically assigning ports
Available as of Camel 2.7
Tests that use port numbers will fail if that port is already on use. AvailablePortFinder provides methods for finding unused port numbers at runtime.
Setup CamelContext once per class, or per every test method
Available as of Camel 2.8
The Camel Test kit will by default setup and shutdown CamelContext per every test method in your test class. So for example if you have 3 test methods, then CamelContext is started and shutdown after each test, that is 3 times.
This feature is also supported in camel-testng
When using this the CamelContext will keep state between tests, so have that in mind. So if your unit tests start to fail for no apparent reason, it could be due this fact. So use this feature with a bit of care.
You may want to do this once, to share the CamelContext between test methods, to speedup unit testing. This requires to use JUnit 4! In your unit test method you have to extend the org.apache.camel.test.junit4.CamelTestSupport or the org.apache.camel.test.junit4.CamelSpringTestSupport test class and override the isCreateCamelContextPerClass method and return true as shown in the following example: