Angular Jasmine模拟提供程序，具有Angluar 9的方法和属性

我试图模仿angularx社交登录npm包。我想要的是默认值应该是创建测试才能通过。在我的测试规范中，我有：

  let component: Component;
  let fixture: ComponentFixture<Component>;
  let spy;

  beforeEach(async(() => {
    spy = jasmine.createSpyObj('SocialAuthService', ['signIn', 'signOut'], ['authState']);
    TestBed.configureTestingModule({
      declarations: [
        Component
      ],
      providers: [
        { provide: SocialAuthService, useValue: spy }
      ]
    })
      .compileComponents();
  }));

  beforeEach(() => {
    fixture = TestBed.createComponent(Component);
    component = fixture.componentInstance;
    fixture.detectChanges();
  });

  it('should create', () => {
    expect(component).toBeTruthy();
  });

上述结果是可以观察到的。但是，当我在每一行之前的第一行中添加这一行代码时：

spy.authState.and.returnValue(of());

---

它表示无法读取未定义的属性和。在网上做了一些研究后，我发现很多建议是使用spyOnProperty，但是当我使用类似于

spyOnProperty（spy，'authState'，'get'）获取错误失败：：authState未声明为可配置。我真的不知道如何处理这个问题。如果您能提供任何帮助，我将不胜感激。
我认为您使用的是
jasmine.createSpyObj
。它只需要两个参数，而不是三个

第一个参数是spy的字符串名称，第二个参数是要模拟的公共方法数组。看到您有
this.socialAuthService.getAuthState（）
，您需要在第二个参数中添加
getAuthState

试试这个：

 let component: Component;
  let fixture: ComponentFixture<Component>;
  let spy;

  beforeEach(async(() => {
    // add all other public properties required into the second argument inside of the array ** in this case remove it since you don't need it
    spy = jasmine.createSpyObj('SocialAuthService', []);
    TestBed.configureTestingModule({
      declarations: [
        Component
      ],
      providers: [
        { provide: SocialAuthService, useValue: spy }
      ]
    })
      .compileComponents();
  }));

  beforeEach(() => {
    fixture = TestBed.createComponent(HeaderComponent);
    component = fixture.componentInstance;
    // I am not sure when you require the value but let's assume you need it in the ngOnInit
   // so we have to put it here
    // spy.getAuthState.and.returnValue(of(null)); // now we are mocking the return value of getAuthState, ** comment out this line, you don't need it
    spy.authState = of(null); // ** mock it to what you would like here
    fixture.detectChanges();
  });

  it('should create', () => {
    expect(component).toBeTruthy();
  });

let组件：组件；
let夹具：组件夹具；
让间谍；
beforeach（异步（（）=>{
//将所需的所有其他公共属性添加到数组**内的第二个参数中。在本例中，请删除它，因为您不需要它
spy=jasmine.createSpyObj（'SocialAuthService'，[]）；
TestBed.configureTestingModule({
声明：[
组成部分
],
供应商：[
{提供：SocialAuthService，useValue:spy}
]
})
.compileComponents（）；
}));
在每个之前（（）=>{
fixture=TestBed.createComponent（HeaderComponent）；
组件=fixture.componentInstance；
//我不确定您何时需要该值，但假设您在ngOnInit中需要它
//所以我们必须把它放在这里
//spy.getAuthState.and.returnValue（of（null））；//现在我们模拟getAuthState的返回值，**注释掉这行，您不需要它
spy.authState=of（null）；//**根据您的需要在此处对其进行模拟
fixture.detectChanges（）；
});
它（'应该创建'，（）=>{
expect（component.toBeTruthy（）；
});
很抱歉我写错了，我的意思是我需要测试这个。SocialAuthService.authState，它是一个属性而不是一个方法。啊，我看到yep spy.authState=of（null）工作得很好。
 let component: Component;
  let fixture: ComponentFixture<Component>;
  let spy;

  beforeEach(async(() => {
    // add all other public properties required into the second argument inside of the array ** in this case remove it since you don't need it
    spy = jasmine.createSpyObj('SocialAuthService', []);
    TestBed.configureTestingModule({
      declarations: [
        Component
      ],
      providers: [
        { provide: SocialAuthService, useValue: spy }
      ]
    })
      .compileComponents();
  }));

  beforeEach(() => {
    fixture = TestBed.createComponent(HeaderComponent);
    component = fixture.componentInstance;
    // I am not sure when you require the value but let's assume you need it in the ngOnInit
   // so we have to put it here
    // spy.getAuthState.and.returnValue(of(null)); // now we are mocking the return value of getAuthState, ** comment out this line, you don't need it
    spy.authState = of(null); // ** mock it to what you would like here
    fixture.detectChanges();
  });

  it('should create', () => {
    expect(component).toBeTruthy();
  });