Безголовый Chrome тест кармы - невозможно прочитать свойство 'innerText' из null

Question

Мой тест для компонента ниже продолжает сбой с сообщением об ошибке:

HeadlessChrome 78.0.3882 (Windows 10.0.0) LoginButtonGroupComponent : should have option to sign in with Google FAILED
    Failed: Cannot read property 'innerText' of null

Однако он проходит для теста should have option to sign in with email address. Есть идеи, что не так?

Тест

import { LoginButtonGroupComponent } from './login-button-group.component';
import { FormsModule } from '@angular/forms';
import { async, inject, TestBed } from '@angular/core/testing';
import { CUSTOM_ELEMENTS_SCHEMA } from '@angular/core';
import { TestStore } from '../../../core/core.spec';
import { State } from '../../../core/store/auth/auth.reducer';
import { Store } from '@ngrx/store';

describe('LoginButtonGroupComponent', () => {
  beforeEach(async(() => {
    TestBed.configureTestingModule({
      schemas: [CUSTOM_ELEMENTS_SCHEMA],
      imports: [FormsModule],
      providers: [
        { provide: Store, useClass: TestStore }
      ],
      declarations: [LoginButtonGroupComponent]
    }).compileComponents().then(() => {
    });
  }));
  describe(':', () => {
    let fixture, app;
    let store: TestStore<State>;

    beforeEach((inject([Store], (testStore: TestStore<State>) => {
      store = testStore;
      store.setState({user: null, error: null});
      fixture = TestBed.createComponent(LoginButtonGroupComponent);
      app = fixture.debugElement.componentInstance;
    })));

    afterEach(() => {
      fixture.destroy();
      app = null;
    });

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

    it('should have option to sign in with Google', async(() => {
      expect(document.getElementById('googleSignIn').innerText.trim()).toBe('Sign in with Google');
    }));

    it('should have option to sign in with Facebook', async(() => {
      expect(document.getElementById('facebookSignIn').innerText.trim()).toBe('Sign in with Facebook');
    }));

    it('should have option to sign in with email address', async(() => {
      expect(document.getElementById('emailSignIn').innerText.trim()).toBe('or use your email address');
    }));
  });
});

Компонент

<p [ngClass]="setButtonAlignment(position)">
  <button (click)="googleSignIn()" *ngIf="!(isMobile | async)?.matches" class="btn btn-label btn-google"
          type="button">
    <label id="googleSignIn">
      <fa-icon [icon]="['fab', 'google']" size="xs"></fa-icon>
    </label> Sign in with Google
  </button>
  <button (click)="mobileGoogleSignIn()" *ngIf="(isMobile | async)?.matches" class="btn btn-label btn-google"
          type="button">
    <label id="mobileGoogleSignIn">
      <fa-icon [icon]="['fab', 'google']" size="xs"></fa-icon>
    </label> Sign in with Google
  </button>
  <button (click)="facebookSignIn()" *ngIf="!(isMobile | async)?.matches" class="btn btn-label btn-facebook"
          type="button">
    <label id="facebookSignIn">
      <fa-icon [icon]="['fab', 'facebook-f']" size="xs"></fa-icon>
    </label> Sign in with Facebook
  </button>
  <button (click)="mobileFacebookSignIn()" *ngIf="(isMobile | async)?.matches" class="btn btn-label btn-facebook"
          type="button">
    <label id="mobileFacebookSignIn">
      <fa-icon [icon]="['fab', 'facebook-f']" size="xs"></fa-icon>
    </label> Sign in with Facebook
  </button>
</p>
<p [ngClass]="setButtonAlignment(position)">
  <small>
    <a class="text-muted small-2" id="emailSignIn" routerLink="/register">or use your email address&nbsp;&nbsp;<fa-icon
      [icon]="['fas', 'long-arrow-alt-right']" size="xs"></fa-icon>
    </a>
  </small>
</p>

Answer 1

Я думаю, что эта кнопка не существует в момент, когда выполняется этот тестовый прогон, потому что вы визуализируете ее с asyn c pipe. Попробуйте использовать detectChanges () , возможно, это вам поможет:

 it('should have option to sign in with Facebook', async(() => {
   component = fixture.componentInstance;
   component.ngOnInit();
   fixture.detectChanges();
 expect(document.getElementById('facebookSignIn').innerText.trim()).toBe('Sign in with Facebook');
 }));

Мне действительно интересно, почему это не работает для вас. Я попытался смоделировать подобную ситуацию, и все работает отлично.

export interface IsMobile {
  matches: string;
}

export class UserProfileComponent implements OnInit {
  isMobile: Observable<IsMobile>;
  breikPoint = new BehaviorSubject<IsMobile>(null);

  ngOnInit(): void {
    this.isMobile = this.breikPoint.asObservable();
  }

  changeView() {
    // simulate change the view
    this.breikPoint.next({matches: '320'});
  }
}

 <button id="facebook" (click)="changeView()" *ngIf="!(isMobile | async)?.matches">Click</button>

 it('should display button and hide after ckick', async(() => {
component = fixture.componentInstance;
component.ngOnInit();
fixture.detectChanges();
const button = fixture.debugElement.query(By.css('#facebook'));
expect(button.nativeElement.innerText).toEqual('Click');

button.triggerEventHandler('click', null);
fixture.detectChanges();
const buttonAfterClick = fixture.debugElement.query(By.css('#facebook'));
expect(buttonAfterClick).toEqual(null);}));