如何使用 then 块对返回 Promise 的函数进行单元测试

Question

我有这段代码来使用 OAuth2 初始化身份验证，并在访问我的应用程序之前将用户重定向到身份验证服务器

import {Component} from '@angular/core';
import {JwksValidationHandler, OAuthService} from 'angular-oauth2-oidc';
import {authConfig} from './sso.config';

@Component({
  selector: 'app-root',
  templateUrl: './app.component.html'
})

export class AppComponent {

  constructor(private oauthService: OAuthService) {}

  async initAuth(): Promise<any> {
    return new Promise<void>((resolveFn, rejectFn) => {
      this.oauthService.configure(authConfig);
      this.oauthService.tokenValidationHandler = new JwksValidationHandler();
      this.oauthService.loadDiscoveryDocumentAndTryLogin().then(() => {
        if (this.oauthService.hasValidAccessToken()) {   // ----------------> My test can't get in this part
          this.oauthService.setupAutomaticSilentRefresh();
          resolveFn();
        }else {
          this.oauthService.initCodeFlow();
          rejectFn();
        }
      });// --------------------------------> It goes directly here and gives me: SPEC HAS NO EXPECTATIONS
    });
  }

}

我想使用 Jasmine 和 Karma 对这部分进行单元测试，我的测试如下所示：

describe('AppComponent', () => {
  let component: AppComponent;
  let fixture: ComponentFixture<AppComponent>;

  const oauthServiceMock = {
    oauthService: {
      loadDiscoveryDocumentAndTryLogin(): Promise<true> {
        return new Promise<true>(resolve => resolve());
      }
    }
  };

  beforeEach(waitForAsync(() => {
    TestBed.configureTestingModule({
      imports: [OAuthModule.forRoot(), HttpClientTestingModule],
      providers: [
       {provide: AppComponent, useValue: oauthServiceMock}
      ],
      declarations: [
        AppComponent
      ],
      schemas: [CUSTOM_ELEMENTS_SCHEMA]
    }).compileComponents();

    fixture = TestBed.createComponent(AppComponent);
    component = fixture.componentInstance;
    fixture.detectChanges();

  }));

  it('Test for initAuth', fakeAsync(() => {

    const spy = spyOn(oauthServiceMock.oauthService, 'loadDiscoveryDocumentAndTryLogin').and.returnValue(Promise.resolve(true));

    component.initAuth().then(() => {
      tick(5000);
      expect(spy).toHaveBeenCalled();

    });

  }));

});

我的测试无法进入块然后我不知道我错过了什么。

Answer 1

我认为您错误地提供了模拟函数。

更改为：

const oauthServiceMock = {
    oauthService: {
      loadDiscoveryDocumentAndTryLogin(): Promise<true> {
        return new Promise<true>(resolve => resolve());
      }
    }
  };

更改

    oauthService: {
      loadDiscoveryDocumentAndTryLogin(): Promise<true> {
        return new Promise<true>(resolve => resolve());
      }
    }

为： 更改

providers: [
       {provide: AppComponent, useValue: oauthServiceMock}
      ],

为：

providers: [
       {provide: OAuthService, useValue: oauthServiceMock}
      ],

我们需要为 OAuthService 而不是 AppComponent 提供模拟。这应该有望解决您的问题。