<dependency>
    <groupId>org.springframework</groupId>
    <artifactId>spring-test</artifactId>
    <version>3.2.3.RELEASE</version>
</dependency>
 
<!-- This is for mocking the service -->
 
<dependency>
    <groupId>org.mockito</groupId>
    <artifactId>mockito-all</artifactId>
    <version>1.9.5</version>
    <scope>test</scope>
</dependency>
 
<!-- Optional -->
<dependency>
    <groupId>org.hamcrest</groupId>
    <artifactId>hamcrest-core</artifactId>
    <version>1.3</version>
    <scope>test</scope>
</dependency>
 
<dependency>
    <groupId>org.hamcrest</groupId>
    <artifactId>hamcrest-library</artifactId>
    <version>1.3</version>
    <scope>test</scope>
</dependency>

  
@Controller
public class IndexController {
 
    public static final String PAGE_INDEX = "index";
    public static final String PAGE_SHOW = "show";
 
    @Autowired
    SampleService sampleService;
 
    @RequestMapping(value = "/", method = RequestMethod.GET)
    public ModelAndView index() {
        return new ModelAndView(PAGE_INDEX, "signupForm", new SignupForm());
    }
 
    @RequestMapping(value = "/create", method = RequestMethod.POST)
    public String create(Model model, @Valid SignupForm signupForm, BindingResult result) {
 
        String returnPage = PAGE_INDEX;
 
        if (!result.hasErrors()) {
            try {
                model.addAttribute("signupForm", sampleService.saveFrom(signupForm));
                returnPage = PAGE_SHOW;
            } catch (InvalidUserException e) {
                model.addAttribute("page_error", e.getMessage());
            }
        }
        return returnPage;
    }
}

  
public class IndexControllerTest {
 
    @Mock
    private SampleService sampleService;
 
    @InjectMocks
    private IndexController indexController;
 
    private MockMvc mockMvc;
 
    @Before
    public void setup() {
 
        // Process mock annotations
        MockitoAnnotations.initMocks(this);
 
        // Setup Spring test in standalone mode
        this.mockMvc = MockMvcBuilders.standaloneSetup(indexController).build();
 
    }
 
    @Test
    public void testCreateSignupFormInvalidUser() throws Exception {
 
        when(sampleService.saveFrom(any(SignupForm.class)))
                .thenThrow(new InvalidUserException("For Testing"));
 
        this.mockMvc.perform(post("/create")
                .param("email", "mvcemail@test.com")
                .param("firstName", "mvcfirst")
                .param("lastName", "mvclastname"))
                .andExpect(status().isOk())
                .andExpect(forwardedUrl(IndexController.PAGE_INDEX))
                .andExpect(model().attributeExists("page_error"));
    }
}