Write JUnit test for @ExceptionHandler

Question

I am writing a Rest service using Spring MVC. Here is the outline of the class:

 @Controller
 public class MyController{

     @RequestMapping(..)
     public void myMethod(...) throws NotAuthorizedException{...}

     @ExceptionHandler(NotAuthorizedException.class)
     @ResponseStatus(value=HttpStatus.UNAUTHORIZED, reason="blah")
     public void handler(...){...}
 }

I have written my unit tests using the design posted here. The test is basically as follows:

@RunWith(SpringJUnit4ClassRunner.class)
@ContextConfiguration(....)
public class mytest{

    MockHttpServletRequest requestMock;
    MockHttpServletResponse responseMock;
    AnnotationMethodHandlerAdapter handlerAdapter;

@Before
public void setUp() {
    requestMock = new MockHttpServletRequest();
    requestMock.setContentType(MediaType.APPLICATION_JSON_VALUE);
    requestMock.addHeader(HttpHeaders.ACCEPT, MediaType.APPLICATION_JSON_VALUE);

    responseMock = new MockHttpServletResponse();

    handlerAdapter = new AnnotationMethodHandlerAdapter();
}

@Test
public void testExceptionHandler(){
    // setup ....
    handlerAdapter.handle(...);

    // verify
    // I would like to do the following
    assertThat(responseMock.getStatus(), is(HttpStatus.UNAUTHORIZED.value()));
}

}

However, the call to handle is throwing the NotAuthorizedException. I have read that this is by design to be able to unit test that the method throws the appropriate exception, however I would like to write an automated test that the framework is handling this exception appropriately and that the class under test has implemented the handler appropriately. Is there a way to do this?

Please be aware that I do not have access to the actual code in a place where I could post it.

Also, I am limited (for unfortunate reasons) to Spring 3.0.5 or 3.1.2.

Answer 1

Consider using Spring 3.2 and its mvc-test-framework

import static org.springframework.test.web.servlet.setup.MockMvcBuilders.*;
import static org.springframework.test.web.servlet.request.MockMvcRequestBuilders.*;
import static org.springframework.test.web.servlet.result.MockMvcResultMatchers.*;

@RunWith(SpringJUnit4ClassRunner.class)
@WebAppConfiguration
@ContextConfiguration("file:src/main/webapp/WEB-INF/spring/appServlet/servlet-context.xml")
public class WebMvcTest {

    @Autowired
    private WebApplicationContext wac;

    private MockMvc mockMvc;

    @Before
    public void setup() {
        this.mockMvc = MockMvcBuilders.webAppContextSetup(this.wac).build();
    }

    @Test
    public void getFoo() throws Exception {
        this.mockMvc.perform(
            get("/testx")
            .contentType(MediaType.APPLICATION_JSON)
            .accept(MediaType.APPLICATION_JSON)
            )
            .andExpect(status().isUnauthorized());
    }
}

Controller code

@Controller
public class MyController {

    public class MyException extends RuntimeException {
    };

    @RequestMapping("/testx")
    public void myMethod() {
        throw new MyException();

    }

    @ExceptionHandler(MyException.class)
    @ResponseStatus(value = HttpStatus.UNAUTHORIZED, reason = "blah")
    public void handler() {
        System.out.println("handler processed");
    }
}

This "test" passes well.

_{Disclaimer: currently I'm a noob in Spring MVC testing, actually it's my first test.
upd: Thanks to The Drake for the correction.}