使用FakeRequest时模拟内部依赖项

Question

I'm using Play Framework 2.3.x, and I'd like to test that a call to a specific route such as "/" (its router is using several nested @Inject dependencies) ends by calling a specific method on a injected component.

For instance, a classic controller :

public class MyController extends Controller {
  @Inject private MyService myService;

  public Result index() { myService.foo(); }
  ...

The service impl injects another service that I want to mock:

@Service
public class MyServiceImpl implements MyService {
  @Inject private ExternalService externalService;

  public void foo() { externalService.call(...); }
  ...

I'd like to mock call() and retrieve its args to check if they contains the expected things.

@RunWith(SpringJUnit4ClassRunner.class)
@Profile("test")
@ContextConfiguration(classes = ApiConfiguration.class)
public class MyControllerTest {
  @Test public void test() {
    Result result = routeAndCall(new FakeRequest("GET", "/"), 10000);
    // here, I expect to retrieve and test the args of a mocked externalService.call
  }
}

I'm calling the route with FakeRequest (and do not inject the controller and calling manually the method) for some annotations to be taken into account and to have a http context (used in some area).

I'm using Mockito, I've tried several combinaison but couldn't inject my mock (the real method was always called), such as :

@Before public void initMocks() {
   MockitoAnnotations.initMocks(this);
}

@Mock ExternalService externalService;
...
when(externalService.call().then(invocation -> {
  Object[] args = invocation.getArguments();

Is it possible? Do you have an idea?

I've stumbled upon https://github.com/sgri/spring-reinject/ which seems to fit (didn't tested) but I'd like to not use another project for something I feel can be done without.

Thanks.

Answer 1

The problem reason your DI injector doesn't know anything about this your mock

@Mock ExternalService externalService;

Spring context bean set and Mockito mock set initially doesn't have any intersection.

To fix this you should define mock as part of your Spring configuration. Eg like this

@RunWith(SpringJUnit4ClassRunner.class)
@Profile("test")
@ContextConfiguration(classes = {ApiConfiguration.class, MyControllerTest.MyConfig.class})
public class MyControllerTest {

 @Autowired 
 ExternalService externalService;

  @Test public void test() {
     ...
  }

  @Configuration
  public static class MyConfig {
     @Bean 
     @Primary // it tells Spring DI to select your mock instead of your real ExternalService impl
     public ExternalService mockExternalService() {
         return Mockito.mock(ExternalService.class);
     }     
  }
}

With this code you

1. define additional beans source from MyControllerTest.MyConfig for Spring DI;
2. in mockExternalService method manually create your bean-mock;
3. define this mock is primary implementation for ExternalService and...
4. ...lets Spring to know about your bean-mock and autowire the mock anywhere in your system.

After this

@Autowired 
ExternalService externalService;

you can work with the mock in your tests as usual. Eg define this behavior

Mockito.doThrow(NullPointerException.class).when(externalService).call(...);