模拟测试组件的指令-带茉莉花和卡玛的Angular 8

我试图为具有一些服务和指令的组件编写一个单元测试。该指令用于呈现按登录用户和来宾用户区分的内容

对于“appShowAuthed”，mock指令的默认值为“false”，测试用例通过。但当我尝试更改该值时，它不会重新渲染视图

HTML:

错误：“TypeError:无法读取未定义的属性“startsWith”

我已经在项目中添加了最少的代码，以便在gitHub中重现这个问题

请给我一个更好的方法来解决这个问题

提前感谢

尝试以下操作：

 it('should show Login button and hide My Orders Button for not logged in user', inject(
    [DataStoreService],
    async (injectService: DataStoreService) => {
      fixture.autoDetectChanges(true);
      injectService.isAuthenticated.next(true);
      await fixture.whenStable();
      await fixture.whenRenderingDone();
      expect(
        fixture.debugElement.query(By.css('#logout')),
      ).not.toBeNull();
      expect(fixture.debugElement.query(By.css('#login'))).toBeNull();
    },
  ));

//Passing Case

  it('should show Login button and hide My Orders Button for not logged in user', async () => 
  {
    await fixture.detectChanges();
    expect(fixture.debugElement.query(By.css('#login'))).not.toBeNull();
    expect(fixture.debugElement.query(By.css('#logout'))).toBeNull();
  });



//Failing Case

 it('should show Login button and hide My Orders Button for not logged in user', async () => 
    {
       const datastore = TestBed.get(DataStoreService);
       datastore.isAuthenticated = of(true);

       fixture.detectChanges();
       await fixture.whenStable();
       await fixture.whenRenderingDone();
       expect(fixture.debugElement.query(By.css('#logout'))).not.toBeNull();
       expect(fixture.debugElement.query(By.css('#login'))).toBeNull();
    });

 it('should show Login button and hide My Orders Button for not logged in user', inject(
    [DataStoreService],
    async (injectService: DataStoreService) => {
      fixture.autoDetectChanges(true);
      injectService.isAuthenticated.next(true);
      await fixture.whenStable();
      await fixture.whenRenderingDone();
      expect(
        fixture.debugElement.query(By.css('#logout')),
      ).not.toBeNull();
      expect(fixture.debugElement.query(By.css('#login'))).toBeNull();
    },
  ));