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Blueprint Testing

Available as of Camel 2.10

Testing is a crucial part of any development or integration work. Camel supports the definition of Blueprint routes, but given that Blueprint is an OSGi specific technology, writing unit tests is quite difficult. This library leverages PojoSR (now Felix Connect) which provides a service registry without using a fully compliant OSGi container. This allows defining real unit tests (as opposed to integration tests using Pax Exam. Please make sure all test jars in your classpath are OSGi bundles.

{snippet:lang=java|id=example|url=camel/trunk/components/camel-test-blueprint/src/test/java/org/apache/camel/test/blueprint/DebugBlueprintTest.java}

Here's the Blueprint XML file:

{snippet:lang=xml|id=example|url=camel/trunk/components/camel-test-blueprint/src/test/resources/org/apache/camel/test/blueprint/camelContext.xml}

<dependency>
  <groupId>org.apache.camel</groupId>
  <artifactId>camel-test-blueprint</artifactId>
  <version>2.10</version>
  <scope>test</scope>
</dependency>

Classpath scanning

By default PojoSR test container scans the test classpath for all the OSGi bundles available there. All the bundles with Blueprint descriptor files will be automatically started by the test container. If you would like to prevent particular bundles from being started by the test container, override the getBundleFilter method, just as demonstrated in the snippet below. 

@Override
protected String getBundleFilter() {
  // I don't want test container to scan and load Logback bundle during the test
  return "(!(Bundle-SymbolicName=ch.qos.logback.core))";
}

Keep in mind that not specifying the Blueprint descriptor in the getBlueprintDescriptor method will not prevent the test container from loading a given descriptor. The getBundleFilter method is the proper way of filtering out bundles you don't want to start during the test.

Setting timeout when getting CamelContext

Available as of Camel 2.13.0/2.12.1/2.11.2

CamelBlueprintTestSupport waits 30 seconds for Camel Context to be ready by default, now you can override this value in two ways:

• Globally, by setting org.apache.camel.test.blueprint.camelContextCreationTimeout system property.
• Locally for each test, by overriding getCamelContextCreationTimeout method.

Adding services on startup

Available as of Camel 2.11.2/2.12.0

When using camel-test-blueprint you may do unit tests which requires using shared services which are not available during unit testing, but only in the real OSGi container, for example a shared DataSource.

To make it easier to register services on startup, such as a standalone DataSource or any other service, you can override the method addServicesOnStartup when your unit test class extends CamelBlueprintTestSupport.

In the example below we register a service org.apache.camel.test.blueprint.MyService using the name myService having a property beer=Carlsberg, as shown below:

    @Override
    protected void addServicesOnStartup(Map<String, KeyValueHolder<Object, Dictionary>> services) {
        services.put("myService", asService(myService, "beer", "Carlsberg"));
    }

The asService is a builder method that makes it easy to register a service with a single property. If you need more properties you can use the asService method that takes a Dictionary as argument. And if you do not need any properties, then just pass in null, eg:

services.put("myService", asService(myService, null));

This allows us to use the service by calling a method on it from a Camel Bean component in a route as shown:

    <route>
      <from uri="direct:start"/>
      <to uri="bean:myService"/>
      <to uri="mock:result"/>
    </route>

Notice the bean endpoint uses the service name myService which was the name we registered the service as. You can also use the fully qualified class name instead, which is more common with OSGi.

    @Override
    protected void addServicesOnStartup(Map<String, KeyValueHolder<Object, Dictionary>> services) {
        services.put(MyService.class.getName(), asService(myService, "beer", "Carlsberg"));
    }

And in the route we use the FQN name:

    <route>
      <from uri="direct:start"/>
      <to uri="bean:org.apache.camel.test.blueprint.MyService"/>
      <to uri="mock:result"/>
    </route>

From Camel 2.16.0, an additional addServicesOnStartup method is available to be overridden making it ideal for when needing to specify multiple services with the same interface. 

  @Override
  protected void addServicesOnStartup(List<KeyValueHolder<String, KeyValueHolder<Object, Dictionary>>> services) {
      Dictionary<String, String> dict1 = new Hashtable<String, String>();
      dict1.put("osgi.jndi.service.name", "jdbc/db1");
        
      Dictionary<String, String> dict2 = new Hashtable<String, String>();
      dict2.put("osgi.jndi.service.name", "jdbc/db2");
        
      services.add(asKeyValueService(javax.sql.DataSource.class.getName(), mockService1, dict1));
      services.add(asKeyValueService(javax.sql.DataSource.class.getName(), mockService2, dict2));
    }

The asKeyValueService builder method can be used to construct the necessary parameters to create the service. The method takes in the name of the registered service, the object, and and a Dictionary as arguments.