Mocking Void Methods with Mockito. 4. Mockito Don’t forget to annotate your Testing class with @RunWith(MockitoJUnitRunner.class). However I'm trying to mock a net.sf.ehcacheCache object. IMHO you need to add a @RunWith (some.mockito.TestSuiteIDontRememberName.class) annotated to the test class. Mockito Often we may run into NullPointerException when we try to actually use the instance annotated with @Mock or @Spy: Most of the time, this happens simply because we forget to properly enable Mockito annotations. 22. This is very useful when we have an external dependency in the class want to mock. I tried to do @Autowired step to since I was running into the exception of NullPointer, but it's running into exception even after that. The main issue here is whenever I try to run the test syncLocalOrders_OrderNotEmptySuccessTest (), the code enters to both subscribe and throwable of fun syncLocalOrders (syncOrders: SyncOrders) (this was got by keeping breakpoints.) Mockito Annotations In this line: Mockito.when (valueProducerFactory.createValueProducer ("IdProducer", Collections.emptyList ()).get ()).thenReturn (mappedValue); you are calling get () on the result of the createValueProducer () call, which is null because you haven't mocked it yet. Void methods can be used with Mockito’s doNothing (), doThrow (), and doAnswer () methods, making mocking and verifying intuitive: However, doNothing () is Mockito's default behavior for void methods. Mockito.mock () The Mockito.mock () method allows us to create a mock object of a class or an interface. See point 16 about partial mocks. 3. Mockito annotations Mockito mock examples Answer. You could use Mockito.spy to, well, spy (or partially mock) the act object so that you only record the behavior of secondMethod and execute the actual code for firstMethod. Mockito @Mock. Mockito Tutorial - JournalDev It’s useful when we want to use the mocked object at multiple places because we avoid calling mock() method multiple times. Like this, you first assign a Mock and then replace this instance with another mock. Learn the difference between @Mock and @InjectMocks annotations in mockito.. 1. This magic succeeds, it fails silently or a MockitoException is thrown. Connect and share knowledge within a single location that is structured and easy to search. Mockito mock objects returns null. mockito We can mock an object using @Mock annotation too. Most of the people just forget to specify the test runner, running class for mocking. NullPointerException when using Mockito During unit testing with junit and mockito, we use @Mock and @InjectMocks annotations to create objects and dependencies to be tested.