Camel unit test with cameltestsupport, template is always null

I am doing a simple unit test with Camel. All I want to do is to read JSON content from a file (under resources), send it to a Java class for validation – this is the route that I am trying to test. Whatever I do, the template (which I use to sendBody(json) is always null. Here is my code:

public class RouteTests extends CamelTestSupport {

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

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

    @Autowired
    JSONObject testJson;

    @Before
    public void setUp() throws Exception {
        try {
            final ObjectMapper objectmapper = new ObjectMapper();
            final ClassLoader loader = Thread.currentThread().getContextClassLoader();
            final InputStream stream = loader.getResourceAsStream("test.json");
            testJson = new JSONObject ((Map)objectmapper.readValue(stream, Map.class));

            // Start Camel
            context = new DefaultCamelContext();
            context.addRoutes(createRouteBuilder());
            context.start();
        }
        catch (IOException e) {
        }
    }

    @Test
    public void testSendMatchingMessage() throws Exception {
        //resultEndpoint.expectedBodiesReceived(expectedBody);
        resultEndpoint = getMockEndpoint("mock:result");
        //resultEndpoint = context.getEndpoint("mock:result", MockEndpoint.class);
        resultEndpoint.expectedMessageCount(1);
        template.sendBody("direct:start", testJson);
        resultEndpoint.assertIsSatisfied();
    }

    @Override
    protected RouteBuilder createRouteBuilder() {
        return new RouteBuilder() {
            public void configure() {
                from("direct:start")
                        .filter().method(ValidationProcessor.class, "validate")
                        .to("mock:result");
            }
        };
    }

    @Override
    protected JndiRegistry createRegistry() throws Exception {
        JndiRegistry jndi = super.createRegistry();
        jndi.bind("ValidationProcessor", new ValidationProcessor", ());

        return jndi;
    }
}

Problems I faced:

1. Initially the result end point also was always null. (I used FilterTest.java for reference). Then I had to do an explicit

    resultEndpoint = getMockEndpoint("mock:result");
   

   to resolve that.

2. Then I read that I had to override the createRegistry, but I did not know how to bind. I just used the name of my validation class, but I don’t know if this is right.

   But the template is always null. The null pointer exception (NPE) is at

    template.sendBody("direct:start", testJson);
   

Please also point me to some reading if necessary. The reference code that Apache Camel documentation link to did not even have the starting of the Camel that I do in the setUp method.

Answer

I think you’ve missed out on a lot of the really helpful stuff that CamelTestSupport does for you. It has its own setUp method that you should override. I believe your test should really look something like this:

public class RouteTests extends CamelTestSupport {

    private JSONObject testJson;

    @Override
    public void setUp() throws Exception {
        // REALLY important to call super
        super.setUp();

        ObjectMapper objectmapper = new ObjectMapper();
        ClassLoader loader = Thread.currentThread().getContextClassLoader();
        InputStream stream = loader.getResourceAsStream("test.json");
        testJson = new JSONObject(objectmapper.readValue(stream, Map.class));
    }

    @Override
    protected RouteBuilder createRouteBuilder() {
        return new RouteBuilder() {
            @Override
            public void configure() {
                from("direct:start")
                        .filter().method(ValidationProcessor.class, "validate")
                        .to("mock:result");
            }
        };
    }

    @Test
    public void testSendMatchingMessage() throws Exception {
        MockEndpoint resultEndpoint = getMockEndpoint("mock:result");
        resultEndpoint.expectedMessageCount(1);
        template.sendBody("direct:start", testJson);
        resultEndpoint.assertIsSatisfied();
    }
}

Actually I would remove the override of setUp altogether and put the reading of the test data in to the test method itself. Then it’s clear what the data is being used for and you can eliminate the testJson field.

public class RouteTests extends CamelTestSupport {

    @Override
    protected RouteBuilder createRouteBuilder() {
        return new RouteBuilder() {
            @Override
            public void configure() {
                from("direct:start")
                        .filter().method(ValidationProcessor.class, "validate")
                        .to("mock:result");
            }
        };
    }

    @Test
    public void testSendMatchingMessage() throws Exception {
        ObjectMapper objectmapper = new ObjectMapper();
        ClassLoader loader = Thread.currentThread().getContextClassLoader();
        InputStream stream = loader.getResourceAsStream("test.json");
        JSONObject testJson = new JSONObject(objectmapper.readValue(stream, Map.class));

        MockEndpoint resultEndpoint = getMockEndpoint("mock:result");
        resultEndpoint.expectedMessageCount(1);
        template.sendBody("direct:start", testJson);
        resultEndpoint.assertIsSatisfied();
    }
}

There, much simpler.