how to create RestController in test directory for SpringBoot Application - spring-boot

Question

Im currently writing integration test for SpringBoot Application .
It's functionality is to receive/send request from outside and forward/receive them to another application(APP_2). So there are two systems which needs to be mocked outside System and APP_2 .
HomeController
#Controller
public class HomeController {
#Autowired
ForwardController forwardController;
#RequestMapping("/")
public #ResponseBody
String greeting() {
return forwardController.processGET().toString();
}
}
ForwardController
#Service
public class ForwardController {
#Autowired
private RestTemplate restTemplate;
#Autowired
private Environment environment;
private ResponseEntity sendRequest(String url, HttpMethod method, HttpEntity requestEntity, Class responseType, Object... uriVariables) {
return restTemplate.exchange( url, method, requestEntity, responseType,uriVariables);
}
public ResponseEntity processGET()
{
HttpHeaders headers = new HttpHeaders();
headers.set("Accept", MediaType.APPLICATION_JSON_VALUE);
HttpEntity<?> entity = new HttpEntity<>(headers);
String app_2_url = environment.getProperty(Constants.APP_2_URL);
ResponseEntity<String> response = sendRequest(app_2_url,HttpMethod.GET,entity,String.class);
return response;
}
}
APP_2_CONTROLLER
#Controller
public class App_2_Controller {
#RequestMapping("/app2Stub")
public #ResponseBody
String greeting() {
return "Hello End of world";
}
}
Test Class which simulates the external request behavior to the system:
HTTP_request_Test
#RunWith(SpringRunner.class)
#ActiveProfiles("test")
#SpringBootTest(webEnvironment = SpringBootTest.WebEnvironment.RANDOM_PORT,classes = Application.class)
public class HttpRequestTest {
#LocalServerPort
private int port;
#Autowired
private TestRestTemplate restTemplate;
#Autowired
private Environment environment;
#Test
public void greetingShouldReturnDefaultMessage() throws Exception {
assertThat(this.restTemplate.getForObject("http://localhost:" + port + "/",
String.class)).contains("Hello End of world");
}
}
Here in this test class I'm overriding the properties by having two property file. So when we run test the request would be sent to App_2_Controller ( Mock in my project ) rather than the real App .
QUESTION :
Is there any way to have the APP_2_CONTROLLER inside the test folder ? This is because I don't want to expose the unwanted test endpoint in my Actual application .
Here in the above project , Im changing the URL with properties. Is there a better way to put a controller for the same URL. For simplicity sake lets assume, app_2 url is app.com:9000/serve

Answer 1

Spring already comes with a MockRestServiceServer, that makes this a lot easier so that you don't have to create your own dummy controllers (App_2_Controller). So in your case, you can remove that controller, and write a test like this for ForwardController:
#RunWith(SpringRunner.class)
#SpringBootTest
#ActiveProfiles("test")
public class ForwardControllerTest {
#Autowired
private RestTemplate restTemplate;
#Autowired
private ForwardController forwardController; // Your service
private MockRestServiceServer server;
#Before
public void setUp() {
server = MockRestServiceServer.bindTo(restTemplate).build();
}
#Test
public void processGet_returnsResponseFromAPI() {
server.expect(once(), requestTo("http://app.com:9000/serve"))
.andExpect(method(HttpMethod.GET))
.andRespond(withSuccess("Hello End of world", MediaType.TEXT_PLAIN));
assertThat(forwardController.processGET().getBody()).isEqualTo("Hello End of world"));
}
}
Additionally, you can create a separate test for your actual controller (ForwardController is just a service), mock ForwardController and use MockMvc:
#RunWith(SpringRunner.class)
#WebMvcTest
public class HomeControllerTest {
#Autowired
private HomeController homeController;
#Autowired
private MockMvc mockMvc;
#MockBean
private ForwardController forwardController;
#Test
public void greeting_usesForwardController() {
when(forwardController.expectGET()).thenReturn("Hello End of world");
mockMvc.perform(get("/"))
.andExpect(status().isOk())
.andExpect(content().string(containsString("Hello End of world")));
}
}
In this case, you'll end up with two tests:
One test to verify that RestTemplate is used to capture the proper response from your external REST API.
Another test to verify that HomeController just forwards whatever ForwardController responds.