CODEWITHSUNDEEP
javaspring-bootmockingmockitointegration-testing
L Jones
L Jones

Reputation: 88

How to test REST controller using MockMvc

I have been trying for some time now to test my REST controller endpoints, using MockMvc, Mockito with Cucumber.

I recently had it to work, without the mocking, but since I've tried to mock my tests, I have been receiving NestedServletException: Request processing failed; nested exception is java.lang.NullPointerException

AddressController snippet

@Autowired
private AddressManager addressManager;

@GetMapping(value = "/{id}")
public ResponseEntity<Object> getAddress(@PathVariable("id") Long addressId) {
    return new ResponseEntity<>(addressManager.getAddress(addressId), HttpStatus.OK);
// getAddress calls a data manager layer which then calls addressRepo.findOneById(addressId);
}

@PostMapping(value = "/add")
public ResponseEntity<Object> addAddress(@RequestBody Address address) {
    return new ResponseEntity<>(addressManager.addAddress(address), HttpStatus.OK);
// addAddress calls a data manager layer which then calls addressRepo.save(address);
}

AddressStepDefs snippet

@RunWith(MockitoJUnitRunner.class) 
@SpringBootTest(webEnvironment= WebEnvironment.MOCK)
@Transactional
@AutoConfigureMockMvc
public class AddressStepDefs {

    private MockMvc mockMvc;

    private ResultActions result; // allows to track result

    @InjectMocks
    private AddressController addressController; 

    @Mock
    private AddressDataManager addressService;

   // given step

   @Before  
   public void setup() throws IOException {
       // must be called for the @Mock annotations to be processed and for the mock service to be injected 
       // into the controller under test.
      MockitoAnnotations.initMocks(this);
      this.mockMvc = MockMvcBuilders.standaloneSetup(new AddressController()).build(); 
   }

   @When("I add a new Address using POST at {string} with JSON:")
   public void i_add_a_new_Address_using_POST_at_with_JSON(String request, String json) throws Exception {
       /** Build a POST request using mockMvc **/
       result = this.mockMvc.perform(post(request).contentType(MediaType.APPLICATION_JSON)
                .content(json.getBytes()).characterEncoding("utf-8"));
    }

    @Then("the response code should be OK {int} and the resulting json should be:")
    public void the_response_code_should_be_OK_and_the_resulting_json_should_be(Integer responseCode, 
    String json) throws Exception {
        result.andExpect(status().is(responseCode));
        result.andExpect(content().string(json));
    }

    @When("I request to view an Address with id {int} at {string}")
    public void i_request_to_view_an_Address_with_id_at(Integer id, String request) throws Exception {
        /** Build a GET request **/
        result = this.mockMvc.perform(get(request + id).contentType(MediaType.APPLICATION_JSON));
    }

Upvotes: 0

Views: 1444

Answers (1)

user4695271
user4695271

Reputation:

Let's assume you are using a recent version of Spring Boot (and you don't need Cucumber yet for this), then you would only need AddressStepDefs as:

@WebMvcTest(AddressController.class)
public class AddressStepDefs {
  @MockBean
  private AddressDataManager addressService;

  @Autowired
  private MockMvc mvc;

  ...

  // Depending on how you configured your Spring beans, you might need this; try first without it ;)
  @Configuration
  @ComponentScan(basePackageClasses = AddressController.class)
  static class TestConfig {
    // ...will be used instead of the application's primary configuration
  }
}

@WebMvcTest annotation is convenient here for your use case since it's only used for Spring MVC tests that focuses only on Spring MVC components.

Then a given test could be written like:

@Test
void getAll_WhenRecordsExist() throws Exception { // HTTP 200 (OK)
  final Collection<Address> expected = Arrays.asList(AddressFactory.random(), AddressFactory.random());
  Mockito.when(addressService.searchAll()).thenReturn(expected);
  mvc.perform(get("/addresses").accept(MediaType.APPLICATION_JSON))
     // .andDo(MockMvcResultHandlers.print())
      .andExpect(header().string(HttpHeaders.CONTENT_TYPE, MediaType.APPLICATION_JSON_VALUE))
      .andExpect(status().isOk())
      .andExpect(content().json(mapper.writeValueAsString(expected))); // ...you need Jackson's object mapper injected also as part of a class' member
  Mockito.verify(service).searchAll();
}

If you are mocking addressService this is not an integration test, IMHO.

Upvotes: 1

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