Question

我有一项我想测试的服务：

@Injectable()
export class AuthenticationService {
  initialAuthStatus = this.authenticationStatus.first();

  constructor(private adalService: AdalService,
              private settingsProvider: SettingsProvider) { }


  public get authenticationStatus(): any {
    return this.adalService.userInfo.authenticationStatus;
  }
}

对服务的测试：

describe('AuthenticationService', () => {
    let mockAdalService: any;
    let adalService: any;
    let service: any;
    let mockSettingsProvider: any;
    beforeEach(() => {
        TestBed.configureTestingModule({
          providers: [
            AuthenticationService, 
            AdalService,
            { provide: SettingsProvider, useClass: MockSettingsProvider },
            { provide: AdalService, useClass: MockAdalService }
          ]
        });

        mockAdalService = new MockAdalService();
        adalService = new AdalService();
        mockSettingsProvider = new MockSettingsProvider();
    });

    it('should be created', inject([AuthenticationService], (service: AuthenticationService) => {
        expect(service).toBeTruthy();
    }));
});

但是，测试失败并显示以下错误消息：

AuthenticationService should be created
TypeError: Cannot read property 'authenticationStatus' of undefined

它与身份验证状态的获取有关，但我无法确切地知道它失败的原因。

非常感谢任何帮助：）

Answer 1

在该行的顶部，在此行中，您声明了类属性initialAuthStatus：

initialAuthStatus = this.authenticationStatus.first();

this.authenticationStatus尚未初始化，为您提供错误消息。为了使它工作，将该行放在ngOnInit（）方法中，并将纯声明部分保留在类的顶部。

initialAuthStatus;
...
ngOnInit(){
    this.initialAuthStatus = this.authenticationStatus;
}
...
...

Karma：无法读取未定义的属性*

1 个答案: