Nullpointerexception EasyMock when testing Controller

Question

I want to test my controller class and its methods.

My Controller method looks like this:

@RequestMapping(value = "/updateUserStory/{usid}", method = RequestMethod.GET)
public String updateUserStory(@PathVariable("trrid") Integer trrID, @PathVariable("usid") Integer userstoryID, Model model ){
    UserStory userStory = this.userStoryService.getUserStoryById(userstoryID);

    model.addAttribute("userstory", userStory);
    model.addAttribute("trrID", trrID);

    return "updateUserStory";
}

My test method looks like this:

public void updateUserStory() throws Exception {
    Model model = mockModel();

    UserStory userStory = new UserStory();
    userStory.setId(1);

    EasyMock.expect(userStoryService.getUserStoryById(1)).andReturn(userStory);
    EasyMock.replay(userStoryService);

    String test = controller.updateUserStory(1, 1, model );

    EasyMock.verify(userStoryService);

    Assert.assertEquals("updateUserStory", test);
}

I added @Mock above for the userStoryService

@Mock
private UserStoryServiceImpl userStoryService;

and @TestSubject for the UserStoryController (In the test simply called controller).

@TestSubject
UserStoryController controller = new UserStoryController();

When running the test I keep getting A NullPointerException at the EasyMock.expect line. I don't know how this is failing. I am mocking the right method.

Answer 1

I see two possible reasons.

1. You haven't used any runner or rule.

To inject mocks, EasyMock needs a JUnit rule

@Rule
public EasyMockRule mocks = new EasyMockRule(this);

or a runner

@RunWith(EasyMockRunner.class)
public class MyTest {

2. The field type is UserStoryService

Not UserStoryServiceImpl . So you should mock UserStoryService instead.