如何在Spring Boot中为RestTemplate编写JUnit测试

Question

I have never written a JUnit test for a Spring Boot application. My Service (localhost) calls via RestTemplate a service, which sends me a response. Can someone, please, give me a small example with my class structure? Or does anybody know a good documentation for my case?

UIController:

@RequestMapping("/my-service")
public interface MyUIController {

    @RequestMapping(method=RequestMethod.GET, value= "/user", produces="application/json")
    public List<User> getUser(HttpServletRequest request,  HttpServletResponse response);
}

RestController:

@RestController
public class MyUIRestController implements MyUIController {

  @Autowired
  private MyUIService myUIService;

  public List<User> getUser(HttpServletRequest request,  HttpServletResponse response) {
        try {
          return myUIService.getUser(request, response);
        } catch (Exception e) {
            e.printStackTrace();
        }

        return null;
    }
}

MyUIService:

@Service
public class MyUIService {
   public List<User> getUser(HttpServletRequest request, HttpServletResponse response) throws IOException {

        String url = this.webServiceProperties.webUserBaseURL+"searchUser";

        MultiValueMap<String, String> params = new LinkedMultiValueMap<String, String>();
        params.add("firstName", request.getParameter("firstName"));

        UriComponents uriComponents = UriComponentsBuilder.fromHttpUrl(url).queryParams(params).build().encode();

        HttpHeaders requestHeaders = new HttpHeaders();
        requestHeaders.setAccept(Collections.singletonList(new MediaType("application","json")));
        HttpEntity<?> requestEntity = new HttpEntity<Object>(requestHeaders);

        RestTemplate restTemplate = new RestTemplate();
        restTemplate.getMessageConverters().add(new MappingJackson2HttpMessageConverter());

        ResponseEntity<List<User>> responseEntity = restTemplate.exchange(
                uriComponents.toUri(), 
                HttpMethod.GET, requestEntity, 
                new ParameterizedTypeReference<List<User>>() {});

        return responseEntity.getBody();

    }
}

What exactly do I have to test, the service or the RestController ? As you can see, I am calling another service. Do I need to make mocks or can I test my Controller/Service directly from the service, which I am calling right now?

Thanks in advance!

Answer 1

It is a good idea to test the RestController , by exposing the getUser() method of your MyUIRestController as an endpoint.

You can use Spring MVC Test framework to test your controllers. A simple google search for "Spring Rest Controller test" redirected me to the following links:

https://www.petrikainulainen.net/programming/spring-framework/unit-testing-of-spring-mvc-controllers-rest-api/

http://blog.zenika.com/2013/01/15/spring-mvc-test-framework/

Also you can refer to Spring Documentation below:

http://docs.spring.io/spring-security/site/docs/current/reference/html/test-mockmvc.html