How to write a unit test for a Spring Boot Controller endpoint

Question

I have a sample Spring Boot app with the following

Boot main class

@SpringBootApplication
public class DemoApplication {

    public static void mai         


        

Answer 1

Let assume i am having a RestController with GET/POST/PUT/DELETE operations and i have to write unit test using spring boot.I will just share code of RestController class and respective unit test.Wont be sharing any other related code to the controller ,can have assumption on that.

@RestController
@RequestMapping(value = “/myapi/myApp” , produces = {"application/json"})
public class AppController {


    @Autowired
    private AppService service;

    @GetMapping
    public MyAppResponse get() throws Exception {

        MyAppResponse response = new MyAppResponse();
        service.getApp().stream().forEach(x -> response.addData(x));    
        return response;
    }


    @PostMapping
    public ResponseEntity create(@RequestBody AppRequest request) throws Exception {
        //Validation code       
        service.createApp(request);

        return ResponseEntity.ok(HttpStatus.OK);
    }

    @PutMapping
    public ResponseEntity update(@RequestBody IDMSRequest request) throws Exception {

        //Validation code
        service.updateApp(request);

        return ResponseEntity.ok(HttpStatus.OK);
    }

    @DeleteMapping
    public ResponseEntity delete(@RequestBody AppRequest request) throws Exception {

        //Validation        
        service.deleteApp(request.id);

        return ResponseEntity.ok(HttpStatus.OK);
    }

}

@RunWith(SpringJUnit4ClassRunner.class)
@SpringBootTest(classes = Main.class)
@WebAppConfiguration
public abstract class BaseTest {
   protected MockMvc mvc;
   @Autowired
   WebApplicationContext webApplicationContext;

   protected void setUp() {
      mvc = MockMvcBuilders.webAppContextSetup(webApplicationContext).build();
   }
   protected String mapToJson(Object obj) throws JsonProcessingException {
      ObjectMapper objectMapper = new ObjectMapper();
      return objectMapper.writeValueAsString(obj);
   }
   protected  T mapFromJson(String json, Class clazz)
      throws JsonParseException, JsonMappingException, IOException {

      ObjectMapper objectMapper = new ObjectMapper();
      return objectMapper.readValue(json, clazz);
   }
}

public class AppControllerTest extends BaseTest {

    @MockBean
    private IIdmsService service;

    private static final String URI = "/myapi/myApp";


   @Override
   @Before
   public void setUp() {
      super.setUp();
   }

   @Test
   public void testGet() throws Exception {
       AppEntity entity = new AppEntity();
      List dataList = new ArrayList();
      AppResponse dataResponse = new AppResponse();
      entity.setId(1);
      entity.setCreated_at("2020-02-21 17:01:38.717863");
      entity.setCreated_by(“Abhinav Kr”);
      entity.setModified_at("2020-02-24 17:01:38.717863");
      entity.setModified_by(“Jyoti”);
            dataList.add(entity);

      dataResponse.setData(dataList);

      Mockito.when(service.getApp()).thenReturn(dataList);

      RequestBuilder requestBuilder =  MockMvcRequestBuilders.get(URI)
                 .accept(MediaType.APPLICATION_JSON);

        MvcResult mvcResult = mvc.perform(requestBuilder).andReturn();
        MockHttpServletResponse response = mvcResult.getResponse();

        String expectedJson = this.mapToJson(dataResponse);
        String outputInJson = mvcResult.getResponse().getContentAsString();

        assertEquals(HttpStatus.OK.value(), response.getStatus());
        assertEquals(expectedJson, outputInJson);
   }

   @Test
   public void testCreate() throws Exception {

       AppRequest request = new AppRequest();
       request.createdBy = 1;
       request.AppFullName = “My App”;
       request.appTimezone = “India”;

       String inputInJson = this.mapToJson(request);
       Mockito.doNothing().when(service).createApp(Mockito.any(AppRequest.class));
       service.createApp(request);
       Mockito.verify(service, Mockito.times(1)).createApp(request);

       RequestBuilder requestBuilder =  MockMvcRequestBuilders.post(URI)
                                                             .accept(MediaType.APPLICATION_JSON).content(inputInJson)
                                                             .contentType(MediaType.APPLICATION_JSON);

       MvcResult mvcResult = mvc.perform(requestBuilder).andReturn();
       MockHttpServletResponse response = mvcResult.getResponse();
       assertEquals(HttpStatus.OK.value(), response.getStatus());

   }

   @Test
   public void testUpdate() throws Exception {

       AppRequest request = new AppRequest();
       request.id = 1;
       request.modifiedBy = 1;
        request.AppFullName = “My App”;
       request.appTimezone = “Bharat”;

       String inputInJson = this.mapToJson(request);
       Mockito.doNothing().when(service).updateApp(Mockito.any(AppRequest.class));
       service.updateApp(request);
       Mockito.verify(service, Mockito.times(1)).updateApp(request);

       RequestBuilder requestBuilder =  MockMvcRequestBuilders.put(URI)
                                                             .accept(MediaType.APPLICATION_JSON).content(inputInJson)
                                                             .contentType(MediaType.APPLICATION_JSON);

       MvcResult mvcResult = mvc.perform(requestBuilder).andReturn();
       MockHttpServletResponse response = mvcResult.getResponse();
       assertEquals(HttpStatus.OK.value(), response.getStatus());

   }

   @Test
   public void testDelete() throws Exception {

       AppRequest request = new AppRequest();
       request.id = 1;

       String inputInJson = this.mapToJson(request);
       Mockito.doNothing().when(service).deleteApp(Mockito.any(Integer.class));
       service.deleteApp(request.id);
       Mockito.verify(service, Mockito.times(1)).deleteApp(request.id);

       RequestBuilder requestBuilder =  MockMvcRequestBuilders.delete(URI)
                                                             .accept(MediaType.APPLICATION_JSON).content(inputInJson)
                                                             .contentType(MediaType.APPLICATION_JSON);

       MvcResult mvcResult = mvc.perform(requestBuilder).andReturn();
       MockHttpServletResponse response = mvcResult.getResponse();
       assertEquals(HttpStatus.OK.value(), response.getStatus());

   }

}