angular2 - 如何在http.post单元测试中模拟错误

Question

我正在使用HTTP.post调用为登录方法编写Uni-test，如：

this.http.post( endpoint, creds, { headers: headers})
        .map(res => res.json())
        .subscribe(
        data => this.onLoginComplete(data.access_token, credentials),  
        err => this.onHttpLoginFailed(err),
        () => this.trace.debug(this.componentName, "Login completed.")
    );

问题是我无法模拟错误分支; 每次都被称为onLoginComplete方法;

这是我的测试：

it("check that  Atfer Login, console show an error ", inject(
  [TraceService, Http, MockBackend, WsiEndpointService],
  (traceService: TraceService, http: Http, 
   backend: MockBackend, wsiEndpoint: WsiEndpointService) => {

  let tokenTest: number =  404 ;

  let response: ResponseOptions = null {} // i think i have to modify this

  let connection: any;

  backend.connections.subscribe((c: any) => connection = c);

  let authService: AuthService = new AuthService(http, Service1, Service2);

  authenticationservice.login({ "username": "a", "password": "1" });

  connection.mockRespond(new Response(response));

  expect(ERROR);

}));

再次感谢大家。

Answer 1

首先，您需要通过MockBackend覆盖XHRBackend类：

describe('HttpService Tests', () => {
  beforeEachProviders(() => {
    return [
      HTTP_PROVIDERS,
      provide(XHRBackend, { useClass: MockBackend }),
      HttpService
    ];
  });

  (...)
});

请注意， HttpService是使用Http对象的服务，我想测试。

然后你需要注入mockBackend并订阅其connections属性。 发送请求时，将调用相应的回调，您可以指定响应元素，如正文。 该服务将接收此响应作为呼叫的响应。 因此，您将能够基于此测试您的服务方法。

下面我将介绍如何测试HttpService的getItems方法：

it('Should return a list of items', inject([XHRBackend, HttpService, Injector], (mockBackend, httpService, injector) => {
  mockBackend.connections.subscribe(
    (connection: MockConnection) => {
      connection.mockRespond(new Response(
        new ResponseOptions({
          body: [ { id: '1', label: 'item1' }]
        })));
      });

  httpService.getItems().subscribe(
    items => {
      expect(items).toEqual([ { id: '1', label: 'item1' }]);
    });
  });
});

这是HttpService的getItems方法的代码：

@Injectable()
export class HttpService {
  constructor(private http:Http) {
  }

  getItems(): Observable<any[]> {
    return this.http.get('/items').map(res => res.json());
  }
}

为了模拟一个错误简单地使用mockError方法，而不是mockResponse之一：

  mockBackend.connections.subscribe(
    (connection: MockConnection) => {
      connection.mockError(new Error('some error'));
    });

Answer 2

你可以模拟这样的错误：

connection.mockError(new Response(new ResponseOptions({
    body: '',
    status: 404,
})));

我创建了一个小班

import {ResponseOptions, Response} from '@angular/http';

export class MockError extends Response implements Error {

    name: any;
    message: any;

    constructor(status: number, body: string = '') {
        super(new ResponseOptions({status, body}));
    }
}

可以这样使用

connection.mockError(new MockError(404));