Mockito Test Failure - Actually, there were zero interactions with this mock

Question

Is there any other way to write test case for below case, needs to write test case for runStudentService method . Tried to write test case as below but its throwing : "wanted but not invoked - Actually, there were zero interactions with this mock."

    @Component
    public class StudentScheduler {

    @Autowired
    private StudentService studentService;

    
    @Scheduled(cron = "${cron.students}")
    public void runStudentService() {
        try {
            studentService.startStudetsTest();
        } catch (Exception e) {
            LOG.error("Error occured during test" + e);
            throw(e);
        }

    }
}

    @RunWith(SpringJUnit4ClassRunner.class)
    public class StudentSchedulerTest {

    @Mock
    private StudentService studentService;

    StudentScheduler scheduler = Mockito.mock(StudentScheduler.class);

    
    @Test
    public void jobRuns() {
        Mockito.doNothing().when(scheduler).runStudentService();
        verify(scheduler, Mockito.times(1)).runStudentService();
    }
    
}

Answer 1

Your mocked StudentScheduler class is not using your mocked studentService instance. Double check the instance studentService instance inside the runStudentService() function is the same instance as your mock studentService.

Pass that mocked studentService instance into the runStudentService() function to be invoked!