How to mock methods which has defined/fixed/hardcoded input?-CodePudding

I have a method in a class lets say doStuff which calls another method of another class execute:

@Component
class A {
 @Autowired
 B b;
 int doStuff(){
  return b.execute(1);
 }
}
@Component
class B {
   int execute(int i){
     return i;
   }
}

Now when I'm trying to mock the method execute, it is throwing nullPointer

@ExtendWith(MockitoExtension.class)
public class ATest{
  @InjectMocks
  A a;
  @Mock
  B b;

  @Test
  doStuffTest(){
   when(b.execute(anyInt()).thenReturn(1);
   assertEquals(1,a.doStuff());
 }

}

It is throwing NullPointer Exception on line when(b.execute(anyInt()).thenReturn(1);

CodePudding user response：

@Autowired annotation is part of Spring, while @Mock is part of Mockito. @Autowired will not be triggered using the Mockito test. Mocked class has to be a constructor where object can be injected by @InjectMock.

If you want to use @Autowired you need a Spring context like @SpringBootTest or others that scan and configuration your project. So, if you would like to mock this bean, you will have to @MockBean annotation.

CodePudding user response：

Issue resolved with @RunWith(MockitoJUnitRunner.class) annotation, without that it's failing