Testing Spring @MVC annotations

Question

I ran into a problem the other day where a @Valid annotation was accidentally removed from a controller class. Unfortunately, it didn't break any of our tests. None of our unit tests actually exercise the Spring AnnotationMethodHandlerAdapter pathway. We just test our controller classes directly.

How can I write a unit or integration test that will correctly fail if my @MVC annotations are wrong? Is there a way I can ask Spring to find and exercise the relevant controller with a MockHttpServlet or something?

Answer 1

In upcoming spring 3.2 (SNAPSHOT available) or with spring-test-mvc (https://github.com/SpringSource/spring-test-mvc) you can do it like this:

first we emulate Validation as we do not want to test the validator, just want to know if validation is called.

public class LocalValidatorFactoryBeanMock extends LocalValidatorFactoryBean
{
    private boolean fakeErrors;

    public void fakeErrors ( )
    {
        this.fakeErrors = true;
    }

    @Override
    public boolean supports ( Class<?> clazz )
    {
        return true;
    }

    @Override
    public void validate ( Object target, Errors errors, Object... validationHints )
    {
        if (fakeErrors)
        {
            errors.reject("error");
        }
    }
}

this is our test class:

@RunWith(SpringJUnit4ClassRunner.class)
@WebAppConfiguration
@ContextConfiguration
public class RegisterControllerTest
{
 @Autowired
 private WebApplicationContext  wac;
 private MockMvc mockMvc;

     @Autowired
     @InjectMocks
     private RegisterController registerController;

     @Autowired
     private LocalValidatorFactoryBeanMock  validator;

  @Before
  public void setup ( )
  {
     this.mockMvc = MockMvcBuilders.webAppContextSetup(this.wac).build();
     // if you want to inject mocks into your controller
             MockitoAnnotations.initMocks(this);
  }

    @Test
    public void testPostValidationError ( ) throws Exception
    {
        validator.fakeErrors();
        MockHttpServletRequestBuilder post = post("/info/register");
        post.param("name", "Bob");
        ResultActions result = getMockMvc().perform(post);
            // no redirect as we have errors
        result.andExpect(view().name("info/register"));
    }

    @Configuration
    @Import(DispatcherServletConfig.class)
    static class Config extends WebMvcConfigurerAdapter
    {
        @Override
        public Validator getValidator ( )
        {
            return new LocalValidatorFactoryBeanMock();
        }

        @Bean
        RegisterController registerController ( )
        {
            return new RegisterController();
        }
    }
}