How to unit test Jersey + Guice: ServiceLocator?

Question

By using HK2's guice-bridge I managed to integrate Jersey 2.x with Guice 3.x.

public class MyApp extends ResourceConfig {

    @Inject
    public MyApp(ServiceLocator serviceLocator) {
        packages("com.mycompany");

        ...

        GuiceBridge.getGuiceBridge().initializeGuiceBridge(serviceLocator);
        GuiceIntoHK2Bridge guiceBridge = serviceLocator.getService(GuiceIntoHK2Bridge.class);
        guiceBridge.bridgeGuiceInjector(GuiceContext.INJECTOR);
    }
}

But now my Jersey tests don't work anymore.

public abstract class AbstractJerseyTest extends JerseyTest {

    public AbstractJerseyTest() throws TestContainerException {
        super(new InMemoryTestContainerFactory());
    }

    protected Application configure() {
        new MyApp(); // ERROR: missing 'ServiceLocator'
    }

}

So where do I get a ServiceLocator for my unit tests?

Answer 1

We made it work with the help of Groovy:

public class MemoryTestContainerFactory implements TestContainerFactory {

    private final Class<? extends Application> jaxrsApplicationClass;

    public MemoryTestContainerFactory(Class<? extends Application> jaxrsApplicationClass) {
        this.jaxrsApplicationClass = jaxrsApplicationClass;
    }

    @Override
    public TestContainer create(URI baseUri, DeploymentContext context) throws IllegalArgumentException {
        return new MemoryTestContainer(jaxrsApplicationClass, baseUri, context);
    }

    private static class MemoryTestContainer implements TestContainer {

        private final URI baseUri;
        private final ApplicationHandler appHandler;
        private final AtomicBoolean started = new AtomicBoolean(false);

        private static final Logger LOGGER = Logger.getLogger(MemoryTestContainer.class.getName());

        MemoryTestContainer(Class<? extends Application> jaxrsApplicationClass, URI baseUri, DeploymentContext context) {
            this.baseUri = UriBuilder.fromUri(baseUri).path(context.getContextPath()).build();    
            this.appHandler = new ApplicationHandler(jaxrsApplicationClass);
        }

        @Override
        public ClientConfig getClientConfig() {
            def provider = new InMemoryConnector.Provider(baseUri, appHandler) // private access (only works with Groovy)
            return new ClientConfig().connectorProvider(provider);
        }

        @Override
        public URI getBaseUri() {
            return baseUri;
        }

        @Override
        public void start() {
            if (started.compareAndSet(false, true)) {
                LOGGER.log(Level.FINE, "Starting InMemoryContainer...");
            } else {
                LOGGER.log(Level.WARNING, "Ignoring start request - InMemoryTestContainer is already started.");
            }
        }

        @Override
        public void stop() {
            if (started.compareAndSet(true, false)) {
                LOGGER.log(Level.FINE, "Stopping InMemoryContainer...");
            } else {
                LOGGER.log(Level.WARNING, "Ignoring stop request - InMemoryTestContainer is already stopped.");
            }
        }
    }
}

It's not pretty, but it works.

Answer 2

Maybe a cleaner approach is to simply use a Feature and configure the bridge there instead of in the ResourceConfig

public class GuiceFeature implements Feature {

    public void configure(FeatureContext context) {
        ServiceLocator serviceLocator = ServiceLocatorProvider.getServiceLocator(context);
        GuiceBridge.getGuiceBridge().initializeGuiceBridge(serviceLocator);
        GuiceIntoHK2Bridge guiceBridge = serviceLocator.getService(GuiceIntoHK2Bridge.class);
        guiceBridge.bridgeGuiceInjector(GuiceContext.INJECTOR);
    }
}

This can be registered like any other feature. Just register it or scan for it with @Provider.

Note the ServiceLocatorProvider is only available Jersey 2.6 and up.

Answer 3

Here is a solution that worked.

The key is to override the configureDeployment() method of JerseyTest and create DeploymentContext by passing the Application specific ResourceConfig.class instead of overriding configure() method and returning ResourceConfig instance, so that The test container initializes the guice-bridge correctly.

This is with following versions of Jersey, Guice, and HK2 guice-bridge

    <jersey.version>2.15</jersey.version>
    <jackson2.version>2.4.4</jackson2.version>
    <hk2.guice.bridge.version>2.4.0-b10</hk2.guice.bridge.version>
    <guice.version>4.0-beta5</guice.version>

1) My Service class

public interface MyService {
    public void hello();
}

2) My Mock Service Impl

public class MyMockServiceImpl implements MyService{
    public void hello() {
        System.out.println("Hi");
    }
} 

3) My Resource class with Guice injected Service

@Path("myapp")
public class MyResource {

    private final MyService myService;

    @Inject
    public MyResource(MyService myService) {
        this.myService = myService;
    }
}

4) My Resource Test class

public class MyResourceTest extends JerseyTestNg.ContainerPerClassTest {

    @Override
    protected Application configure() {
        return null;
    }

    @Override
    protected DeploymentContext configureDeployment() {
        return DeploymentContext.builder(MyTestConfig.class).build();
    }

    // other test and setup/teardown methods
}

5) ResourceConfig class

static class MyTestConfig extends ResourceConfig {

    @Inject
    public MyTestConfig(ServiceLocator serviceLocator) {

        packages("com.myapp.rest");

        GuiceBridge.getGuiceBridge().initializeGuiceBridge(serviceLocator);

        GuiceIntoHK2Bridge guiceBridge = serviceLocator.getService(GuiceIntoHK2Bridge.class);
        guiceBridge.bridgeGuiceInjector(Guice.createInjector(new MyTestModule()));

    }
}

6) My Guice Test Module class

public class MyTestModule implements Module {

    @Override
    public void configure(Binder binder) {
            binder.bind(MyService.class)
               .to(MyMockServiceImpl.class);
    }

}

Answer 4

Note: I have never used Jersey before. However, you should not be calling new MyApp() anymore; otherwise Guice won't work. Instead, I might try something like this:

public abstract class AbstractJerseyTest extends JerseyTest {
    private final Module[] modules;

    public AbstractJerseyTest(Module... modules) throws TestContainerException {
        super(new InMemoryTestContainerFactory());
        this.module = modules;
    }

    protected Application configure() {
        Injector inj = Guice.createInjector(modules);
        return inj.getInstance(MyApp.class);
    }
}

public class ActualTest extends AbstractJerseyTest {
    private static class TestModule extends AbstractModule {
        @Override
        public void configure() {
            // Do your guice bindings here
        }
    }

    public ActualTest() throws TestContainerException {
        super(new TestModule());
    }
}