How can I mock methods of @InjectMocks class?

Question

For example I have handler:

@Component public class MyHandler {    @AutoWired   private MyDependency myDependency;    public int someMethod() {     ...     return anotherMethod();   }    public int anotherMethod() {...} } 

to testing it I want to write something like this:

@RunWith(MockitoJUnitRunner.class} class MyHandlerTest {    @InjectMocks   private MyHandler myHandler;    @Mock   private MyDependency myDependency;    @Test   public void testSomeMethod() {     when(myHandler.anotherMethod()).thenReturn(1);     assertEquals(myHandler.someMethod() == 1);   } } 

But it actually calls anotherMethod() whenever I try to mock it. What should I do with myHandler to mock its methods?

Answer 1

First of all the reason for mocking MyHandler methods can be the following: we already test anotherMethod() and it has complex logic, so why do we need to test it again (like a part of someMethod()) if we can just verify that it's calling?
We can do it through:

@RunWith(MockitoJUnitRunner.class) class MyHandlerTest {    @Spy     @InjectMocks     private MyHandler myHandler;      @Mock     private MyDependency myDependency;      @Test     public void testSomeMethod() {       doReturn(1).when(myHandler).anotherMethod();       assertEquals(myHandler.someMethod() == 1);       verify(myHandler, times(1)).anotherMethod();     }   }   

Note: in case of 'spying' object we need to use doReturn instead of thenReturn(little explanation is here)