Mock object is not being returned

Question

There is a Adapter class which calls another legacyService and legacyService calls legacyDao and I want to mock the Legacy service calls. In the below code SomeBean is returned as null instead of one the one that i created and passed in thenReturn. What could be the issue here?Please help I am new to mocking framework.

public class AdapterImpl implements Adpater{

  //Injected through setter or constructor injection
  private LegacyService legacy;

  public SomeBean myMethod(){
      CommonUtils.someStaticMethod()
      return legacy.legacyService();
  }

}


public class LegacyServiceImpl implements LegacyService{
  //Injected through setter or constructor injection
  private LegacyDAO ldao;//LegacyDAO is an interface

  public SomeBean legacyService(){
      return ldao.legacyDAO();
  }

}

Test class

@RunWith(PowerMockRunner.class)
@PrepareForTest({CommonUtils.class})
public class AdapterImplTest{

  @Mock private LegacyServiceImpl legacyService;

  private LegacyDAO legacyDAO;


  @Before
    public void before(){

        MockitoAnnotations.initMocks(this);
    }

  @Test
  public void myMethodTest(){


      PowerMockito.mockStatic(CommonUtils.class);
      PowerMockito.when(CommonUtils.someStaticMethod()).thenReturn(someString());

      legacyDAO =  PowerMockito.mock(LegacyDAO.class);  
      SomeBean bean = new SomeBean(sometring1,somestring2);

      PowerMockito.when(legacyDAO.legacyDAO().thenReturn(bean);//I am mocking interface method implementation

      legacyService.setLegacyDAO(legacyDAO);

      PowerMockito.when(legacyService.legacyService().thenReturn(bean);//same bean as above

      AdapterImpl impl = new AdapterImpl();
      impl.setLegacyService(legacyService)
      //Below method call is not returning the bean that I constructed above it is being returned as null
      impl.myMethod();
  }

}

Answer 1

The original code posted in the question has many typos like missing parentheses and semi-colons. When I correct them, and fill in some of the methods like AdapterImpl.setLegacyService(), the test passes.

Then, as suggested in my comment, I removed the mocking of LegacyDAO. That mock object should not be needed if LegacyServiceImpl.legacyService() is properly mocked. When I rerun the test, it again passes.

All of which leads me to believe that there is an issue with the injection of the mock LegacyService object into AdapterImpl

FYI here is my passing test code, showing my typo fixes and assumptions about methods not shown in the original question. Hope this helps!

@RunWith(PowerMockRunner.class)
@PrepareForTest({ AdapterImplTest.CommonUtils.class })
public class AdapterImplTest {

    @Mock
    private LegacyServiceImpl legacyService;

//  private LegacyDAO legacyDAO;  // removed, no need to mock

    @Before
    public void before() {

        MockitoAnnotations.initMocks(this);
    }

    @Test
    public void myMethodTest() {

        PowerMockito.mockStatic(CommonUtils.class);
        PowerMockito.when(CommonUtils.someStaticMethod()).thenReturn(someString());

//      legacyDAO = PowerMockito.mock(LegacyDAO.class);
        SomeBean bean = new SomeBean("sometring1", "somestring2");

        // I am mocking interface method implementation
//      PowerMockito.when(legacyDAO.legacyDAO()).thenReturn(bean);
//      legacyService.setLegacyDAO(legacyDAO);

        // same bean as above
        PowerMockito.when(legacyService.legacyService()).thenReturn(bean);

        AdapterImpl impl = new AdapterImpl();
        impl.setLegacyService(legacyService);
        // Below method call is not returning the bean that I constructed above
        // it is being returned as null
        impl.myMethod();
    }

    private String someString() {
        return "hello";
    }

    public class SomeBean {
        public SomeBean(String string, String string2) {
        }
    }

    public interface LegacyService {
        public SomeBean legacyService();
    }

    public interface Adpater {
    }

    public class AdapterImpl implements Adpater {
        // Injected through setter or constructor injection
        private LegacyService legacy;

        public SomeBean myMethod() {
            CommonUtils.someStaticMethod();
            return legacy.legacyService();
        }

        public void setLegacyService(LegacyServiceImpl legacyService) {
            legacy = legacyService;
        }
    }

    public class LegacyServiceImpl implements LegacyService {
        // Injected through setter or constructor injection
        private LegacyDAO ldao;// LegacyDAO is an interface

        public SomeBean legacyService() {
            return ldao.legacyDAO();
        }

        public void setLegacyDAO(LegacyDAO legacyDAO) {
            ldao = legacyDAO;
        }
    }

    public class LegacyDAO {
        public SomeBean legacyDAO() {
            return null;
        }
    }

    public static class CommonUtils {
        public static String someStaticMethod() {
            return "in CommonUtils.someStaticMethod()";
        }
    }

}