[CONF] Apache Camel: Testing (page edited)

confluence Wed, 03 Dec 2008 01:49:32 -0800

Page Edited : CAMEL : Testing

Testing has been edited by James Strachan (Dec 03, 2008).

Content:

Testing

Testing is a crucial activity in any piece of software development or integration. Typically Camel Riders use various different technologies wired together in a variety of patterns with different _expression_ languages together with different forms of Bean Integration and Dependency Injection so its very easy for things to go wrong! . Testing is the crucial weapon to ensure that things work as you would expect.

Camel is a Java library so you can easily wire up tests in whatever unit testing framework you use (JUnit 3.x, 4.x or TestNG). However the Camel project has tried to make the testing of Camel as easy and powerful as possible so we have introduced the following features.

Testing mechanisms

The following mechanisms are supported

Name	Description
Camel Test	is a library letting you easily create Camel test cases using a single Java class for all your configuration and routing without using Spring or Guice for Dependency Injection which does not require an in depth knowledge of Spring+SpringTest or Guice
Spring Testing	uses Spring Test together with either XML or Java Config to dependency inject your test classes
Guice	uses Guice to dependency inject your test classes

In all approaches the test classes look pretty much the same in that they all reuse the Camel binding and injection annotations.

Camel Test Example

Here is the Camel Test example.

public class FilterTest extends CamelTestSupport {


    @EndpointInject(uri="mock:result")
    protected MockEndpoint resultEndpoint;

    @Produce(uri="direct:start")
    protected ProducerTemplate template;

    public void testSendMatchingMessage() throws Exception {
        String expectedBody = "<matched/>";

        resultEndpoint.expectedBodiesReceived(expectedBody);

        template.sendBodyAndHeader(expectedBody, "foo", "bar");

        resultEndpoint.assertIsSatisfied();
    }

    public void testSendNotMatchingMessage() throws Exception {
        resultEndpoint.expectedMessageCount(0);

        template.sendBodyAndHeader("<notMatched/>", "foo", "notMatchedHeaderValue");

        resultEndpoint.assertIsSatisfied();
    }

    @Override
    protected RouteBuilder createRouteBuilder() {
        return new RouteBuilder() {
            public void configure() {
                from("direct:start").filter(header("foo").isEqualTo("bar")).to("mock:result");
            }
        };
    }
}

Notice how it derives from the Camel helper class CamelTestSupport but has no Spring or Guice dependency injection configuration but instead overrides the createRouteBuilder() method.

Spring Test with XML Config Example

Here is the Spring Test example using XML Config.

@ContextConfiguration
public class FilterTest extends AbstractJUnit38SpringContextTests {

    @EndpointInject(uri = "mock:result")
    protected MockEndpoint resultEndpoint;

    @Produce(uri = "direct:start")
    protected ProducerTemplate template;

    @DirtiesContext
    public void testSendMatchingMessage() throws Exception {
        String expectedBody = "<matched/>";

        resultEndpoint.expectedBodiesReceived(expectedBody);

        template.sendBodyAndHeader(expectedBody, "foo", "bar");

        resultEndpoint.assertIsSatisfied();
    }

    @DirtiesContext
    public void testSendNotMatchingMessage() throws Exception {
        resultEndpoint.expectedMessageCount(0);

        template.sendBodyAndHeader("<notMatched/>", "foo", "notMatchedHeaderValue");

        resultEndpoint.assertIsSatisfied();
    }
}

Notice the use of @ContextConfiguration to indicate that by default we should look for the FilterTest-context.xml on the classpath to configure the test case which looks like this

<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xmlns:context="http://www.springframework.org/schema/context"
       xsi:schemaLocation="
       http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-2.5.xsd
       http://activemq.apache.org/camel/schema/spring http://activemq.apache.org/camel/schema/spring/camel-spring.xsd
    ">

  <camelContext xmlns="http://activemq.apache.org/camel/schema/spring">
    <!-- Java version
    from("direct:start").filter(header("foo").isEqualTo("bar")).to("mock:result");
    -->
    <route>
      <from uri="direct:start"/>
      <filter>
        <xpath>$foo = 'bar'</xpath>
        <to uri="mock:result"/>
      </filter>
    </route>

  </camelContext>

</beans>

Spring Test with Java Config Example

Here is the Spring Test example using Java Config.

@ContextConfiguration(
        locations = "org.apache.camel.spring.javaconfig.patterns.FilterTest$ContextConfig",
        loader = JavaConfigContextLoader.class)
public class FilterTest extends AbstractJUnit38SpringContextTests {

    @EndpointInject(uri = "mock:result")
    protected MockEndpoint resultEndpoint;

    @Produce(uri = "direct:start")
    protected ProducerTemplate template;

    @DirtiesContext
    public void testSendMatchingMessage() throws Exception {
        String expectedBody = "<matched/>";

        resultEndpoint.expectedBodiesReceived(expectedBody);

        template.sendBodyAndHeader(expectedBody, "foo", "bar");

        resultEndpoint.assertIsSatisfied();
    }

    @DirtiesContext
    public void testSendNotMatchingMessage() throws Exception {
        resultEndpoint.expectedMessageCount(0);

        template.sendBodyAndHeader("<notMatched/>", "foo", "notMatchedHeaderValue");

        resultEndpoint.assertIsSatisfied();
    }

    @Configuration
    public static class ContextConfig extends SingleRouteCamelConfiguration {
        @Bean
        public RouteBuilder route() {
            return new RouteBuilder() {
                public void configure() {
                    from("direct:start").filter(header("foo").isEqualTo("bar")).to("mock:result");
                }
            };
        }
    }
}

This is similar to the XML Config example above except that there is no XML file and instead the nested ContextConfig class does all of the configuration.

Testing endpoints

Camel provides a number of endpoints which can make testing easier.

Name	Description
DataSet	For load & soak testing this endpoint provides a way to create huge numbers of messages for sending to Components and asserting that they are consumed correctly
Mock	For testing routes and mediation rules using mocks and allowing assertions to be added to an endpoint
Test	Creates a Mock endpoint which expects to receive all the message bodies that could be polled from the given underlying endpoint

The main endpoint is the Mock endpoint which allows expectations to be added to different endpoints; you can then run your tests and assert that your expectations are met at the end.

Stubbing out physical transport technologies

If you wish to test out a route but want to avoid actually using a real physical transport (for example to unit test a transformation route rather than performing a full integration test) then the following endpoints can be useful.

Name	Description
Direct	Direct invocation of the consumer from the producer so that single threaded (non-SEDA) in VM invocation is performed which can be useful to mock out physical transports
SEDA	Delivers messages asynchonously to consumers via a java.util.concurrent.BlockingQueue which is good for testing asynchronous transports

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