how to treat controller exception with mockmvc

Question

I am using MockMVC to test my controller.

I have the following controller:

public class A{

    ...

    @RequestMapping("/get")
    public List<ADTO> get(@RequestParam(defaultValue = "15", required = false) Integer limit) throws IOException {
        if(limit <= 0 || limit >= 50){
            throw new IllegalArgumentException();
        }
        ...
        return aDTOs;
    }

}

And my current test looks like this:

@Test
public void testGetAllLimit0() throws Exception {
    mockMvc.perform(get("/A/get")
            .param("limit","0")
            )
            .andDo(print())
            .andExpect(...);
}

I am instantiating MockMVC with this:

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

How can I take care of that exception thrown in my controller?

Later Edit:

I'm not sure what happened in my code recently but it passes the test:

@Test
public void testGetAllLimit0() throws Exception {
    mockMvc.perform(get("/A/get")
            .param("limit","0")
            )
            .andDo(print())
            .andExpect(status().is(500));
}

It still passes if I replace is(500) with isOk(). And this is not good, I should check somehow for that exception.

If I run a gradle build I get this:

org.springframework.web.util.NestedServletException: Request processing failed; nested exception is java.lang.IllegalArgumentException

Solution 1

Did you try to use a custom ExceptionHandler like here? : https://spring.io/blog/2013/11/01/exception-handling-in-spring-mvc

If you do so you can return custom HTTP response codes and verify them in your test.

Solution 2

Easier way is to inject @ExceptionHandler into your Spring Test Context or it throws exception right in MockMvc.perform() just before .andExpect().

@ContextConfiguration(classes = { My_ExceptionHandler_AreHere.class })
@AutoConfigureMockMvc
public class Test {
    @Autowired
    private MockMvc mvc;

    @Test
    public void test() {
        RequestBuilder requestBuilder = MockMvcRequestBuilders.post("/update")
                .param("branchId", "13000")
                .param("triggerId", "1");
        MvcResult mvcResult = mvc.perform(requestBuilder)
                .andExpect(MockMvcResultMatchers.status().is4xxClientError())
                .andExpect(MockMvcResultMatchers.content().contentType(MediaType.APPLICATION_JSON_UTF8))
                .andExpect(__ -> Assert.assertThat(
                        __.getResolvedException(),
                        CoreMatchers.instanceOf(SecurityException.class)))
                .andReturn();
}

That way MvcResult.getResolvedException() holds @Controller's exception!

• https://stackoverflow.com/a/62910352/173149
• https://stackoverflow.com/a/61016827/173149
• Testing Spring MVC @ExceptionHandler method with Spring MVC Test