如何模拟私有dao变量？

Question

class MyService {
    @Inject
    private Dao dao;

    public void myMethod() {
        //..
        dao.create(object);
        //
    }
}

如何模拟dao.create（）调用？

@RunWith(PowerMockRunner.class)
@PrepareForTest(DAO.class)
public void MyServiceTest {

    @Test
    public void testMyMethod() {
        PowerMockito.mock(DAO.class);

        MyService service = new MyService();
        service.myMethod(); //NPE for dao.create()
    }
}

Answer 1

你不能注射刀。使用mockito，您可以将测试类更改为使用@injectMocks和使用mockito runner。

@RunWith(MockitoJUnitRunner.class)
public void MyServiceTest {
    @Mock
    private Dao dao;
    @InjectMocks
    private MyService myService;
    ...
}

您可以在Inject Mocks API阅读更多关于InjectMocks的信息

更简单的方法是通过构造函数将注入更改为注入。例如，您可以将MyService更改为

class MyService {
    ...
    private final Dao dao;

    @Inject
    public MyService(Dao dao) {
        this.dao = dao;
    } 
    ...
}

...
@Mock
private Dao dao;

@Before
public void setUp() {
    this.dao = mock(Dao.class);
    this.service = new MyService(dao);
}
...

...
   verify(dao).create(argThat(isExpectedObjectBeingCreated(object)));
}

private Matcher<?> isExpectedObjectBeingCreated(Object object) { ... }