Question

我的测试失败，不确定如何解决。我从Jest收到的错误消息似乎是矛盾的，问题与两个Angular HttpTestingController方法的行为有关：verify()和expectOne()。

有问题的测试，在其文件范围内：

import {TestBed, getTestBed} from '@angular/core/testing';
import {HttpClientTestingModule, HttpTestingController} from '@angular/common/http/testing';
import {PrintProjectsService} from './print-projects.service';
import {AppConfig} from '../../app.config';

describe('PrintProjectsService', () => {
  let injector: TestBed;
  let service: PrintProjectsService;
  let appConfig: AppConfig;
  let httpMock: HttpTestingController;

  beforeEach(() => {
    TestBed.configureTestingModule({
      imports: [HttpClientTestingModule],
      providers: [PrintProjectsService, AppConfig]
    });
    injector = getTestBed();
    service = injector.get(PrintProjectsService);
    httpMock = injector.get(HttpTestingController);
    appConfig = injector.get(AppConfig);
  });

  afterEach(() => {
    httpMock.verify();
  });

  //This test passes
  it('should make a GET request to retrieve a printable factory when provided a printable factory id', () => {
    const id = '12345';
    service.getPrintableFactory(id).subscribe();
    const req = httpMock.expectOne(`${appConfig.API_URL}/api/printed-book/v1/printable-factories/${id}/`);
    expect(req.request.method).toBe('GET');
  });

  // This is the one that fails
  it('should make a GET request to retrieve cover image data from the cover service', () => {
    const imageType = 'full';
    service.getCoverImage(12345, '0850X1100FCSTDCO080CW444GXX', imageType).subscribe();
    //httpMock.verify(); //this finds a GET at undefined/cover/api/cover-images/full
    const req = httpMock.expectOne(`${appConfig.API_URL}/cover/api/cover-images/${imageType}`);
    expect(req.request.responseType).toBe('blob');
  });
});

Jest返回此错误消息：

● PrintProjectsService › should make a GET request to retrieve cover image data from the cover service

Expected one matching request for criteria "Match URL: undefined/cover/api/cover-images/full", found none.

  44 |     service.getCoverImage(12345, '0850X1100FCSTDCO080CW444GXX', imageType).subscribe();
> 45 |     const req = httpMock.expectOne(`${appConfig.API_URL}/cover/api/cover-images/${imageType}`);
  46 |     expect(req.request.responseType).toBe('blob');

  at HttpClientTestingBackend.Object.<anonymous>.HttpClientTestingBackend.expectOne (node_modules/@angular/common/bundles/common-http-testing.umd.js:435:19)
  at src/app/services/print-projects/print-projects.service.spec.ts:45:26
  ...
  at Object.testBody.length (node_modules/jest-zone-patch/index.js:50:27)

● PrintProjectsService › should make a GET request to retrieve cover image data from the cover service

Expected no open requests, found 1: GET undefined/cover/api/cover-images/full

  23 |   afterEach(() => {
> 24 |     httpMock.verify();
  25 |   });

错误消息中的URL变量呈现为undefined的事实是不相关的-通过测试中也是如此。

令我困惑的是，在测试中到达expectOne()时，找不到undefined/cover/api/cover-images/full的请求，但是在测试之后，verify()在相同 URL：undefined/cover/api/cover-images/full。当verify()放在测试中undefined/cover/api/cover-images/full之前的行中时，也会在expectOne()处找到GET请求。

为什么expectOne()不能捕获请求，而verify()可以捕获请求？错误消息没有告诉我我需要的一切吗？无论运行jest还是jest --verbose，我似乎都收到相同的错误消息。

Answer 1

我找到了解决此问题的方法，从这里搜集了expectOne()的变体：https://github.com/thymikee/jest-preset-angular/blob/master/example/src/app/service/hero.service.spec.ts#L59

这是通过测试的新版本：

it('should make a GET request to retrieve cover image data from the cover service', () => {
    const imageType = 'full';
    service.getCoverImage(12345, '0850X1100FCSTDCO080CW444GXX', imageType).subscribe();
    const req = httpMock.expectOne((request: HttpRequest<Blob>) => {
      return request.url === `${appConfig.API_URL}/cover/api/cover-images/${imageType}`;
    });
    expect(req.request.method).toBe('GET');
    // the original `expect()` below also passes, but since we already state that the request will return a Blob above, the `expect()` above is a better option
    // expect(req.request.responseType).toBe('blob'); 
  });

似乎url的{{1}}匹配版本（最初使用的）在默认情况下期望expectOne()响应。无论如何，此特定呼叫的JSON响应类型似乎是问题的根源。

带笑话的角度：`verify（）vs.expectOne（）`？

1 个答案: