Mockito - Cannot instantiate @InjectMocks

Question

I have two private fields in my class which I am testing and these two fields are initialized in constructor.

Now when I am trying to call using my class annotated with @InjectMocks, it is throwing exception:

 Cannot instantiate @InjectMocks field named 'ServiceImpl' of type 'class com.test.ServiceImpl'. You haven't provided the instance at field declaration so I tried to construct the instance.

Below is the piece of code.

public class ServiceImpl implements Service {

private OfficeDAO officeDAO ;

private DBDAO dbDAO ;

public ServiceImpl() {
officeDAO = Client.getDaoFactory().getOfficeDAO();
dbDAO = Client.getDaoFactory().getDBDAO();
}

My test class:

@RunWith(MockitoJUnitRunner.class)
public class ServiceImplTest {

    @Mock
    private OfficeDAO officeDAO;

    @Mock
    private DBDAO dbDAO;

    @Mock
    Client client;

    @InjectMocks
    private ServiceImpl serviceImpl;

    @Mock
    private Logger log;

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

Please help me how I can resolve it. Any help will be appreciated.

Solution

You are using @InjectMocks annotation, which creates an instance of ServiceImpl class. Because your constructor is trying to get implementation from factory: Client.getDaoFactory().getOfficeDAO() you have NPE.

Make sure what is returned by Client.getDaoFactory(). I bet it returns null and that's the problem :) Refactor your code, so that DaoFactory is passed via parameter rather than using static.

---

I see you have a different exception right now. But based on the code I cannot really tell more. Please, provide full example of failing test.

Comments

[Arpit Aggarwal]

I am having another dependency which i mocked. In my test class I can see it's mocked but when control is going to service class it is coming as null.

[Arpit Aggarwal]

@Test public void testGetOfficeForOperator() throws Exception { when(asignmentDao.getOfficeForOperator(Mockito.anyString()‌​)).thenReturn( serviceImplTestData.getAssignmentList()); serviceImpl.getOfficeForOperator("ABC", new Date(), new Date());}