Mock services inside another spring service with mockito

Question

I'm facing problems mocking services injected inside of other services within the Spring framework. Here is my code:

@Service("productService")
public class ProductServiceImpl implements ProductService {

    @Autowired
    private ClientService clientService;

    public void doSomething(Long clientId) {
        Client client = clientService.getById(clientId);
        // do something
    }
}

I want to mock the ClientService inside my test, so I tried the following:

@RunWith(SpringJUnit4ClassRunner.class)
@ContextConfiguration(locations = { "classpath:/spring-config.xml" })
public class ProductServiceTest {

    @Autowired
    private ProductService productService;

    @Mock
    private ClientService clientService;

    @Test
    public void testDoSomething() throws Exception {
        when(clientService.getById(anyLong()))
                .thenReturn(this.generateClient());

        /* when I call this method, I want the clientService
         * inside productService to be the mock that one I mocked
         * in this test, but instead, it is injecting the Spring 
         * proxy version of clientService, not my mock.. :(
         */
        productService.doSomething(new Long(1));
    }

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

    private Client generateClient() {
        Client client = new Client();
        client.setName("Foo");
        return client;
    }
}

The clientService inside productService is the Spring proxy version, not the mock that I want. Is it possible to do what I want with Mockito?

Answer 1

I would like to suggest you annotate the Test target with @InjectMock

Currently

    @Autowired
    private ProductService productService;

    @Mock
    private ClientService clientService;

Change to

    @InjectMock
    private ProductService productService;

    @Mock
    private ClientService clientService;

incase you still have NullPointerException for the MockingService => you can use Mockito.any() as arguments. Hopefully, it will help you.

Answer 2

You need to annotate ProductService with @InjectMocks:

@Autowired
@InjectMocks
private ProductService productService;

This will inject the ClientService mock into your ProductService.

Answer 3

There are more ways to achieve this, the most easy way to do this will be don't use field injection, but setter injection which means you should have:

@Autowired
public void setClientService(ClientService clientService){...}

in your service class, then you can inject your mock to the service in test class:

@Before
public void setUp() throws Exception {
    productService.setClientService(mock);
}

important: If this is only a unit test, please consider don't use SpringJUnit4ClassRunner.class, but MockitoJunitRunner.class, so that you can also use field inject for your fields.

Answer 4

In addition to

@Autowired
@InjectMocks
private ProductService productService;

Add the following method

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