Angular 单元测试 - 响应式表单值未更新

Question

我是 Angular 单元测试的新手。
测试场景:html中的表单 View 值等于组件表单值。
电子邮件值由共享值检索并在组件注册表中使用。我可以使用响应式(Reactive)表单从组件中检索电子邮件值，但是当尝试通过 native 元素访问时，它给出了空值。
下面是component.ts

ngOnit(public serviceEmail) {
    this.assignEmailAvailable();
    this.createRegistration();

    }
assignEmailAvailable() {
 if(service.email){
    this.email = serviceEmail.email;
  }
 }   
createRegistration() {
   this.registerForm = new FormGroup({
       email:new FormControl({value:this.email})
    })
}

在 component.spec.ts 中，我将调用此函数并检查两个值是否相同。
组件.spec.ts

 beforeEach(() => {
    fixture = TestBed.createComponent(RegisterComponent);
    component = fixture.componentInstance;
    service = TestBed.get(serviceEmail);
  });
it('Registration Form Creation', fakeAsync(() => {
    service.email = "dsf@gmail.com";

    fixture.detectChanges();

    component.assignEmailAvailable();
    component.createRegisterForm();

    fixture.detectChanges();
    fixture.whenStable().then(() => {
    const email = fixture.debugElement.query(By.css('input[id="email"]')).nativeElement;
//The value is empty even after creating the form using the component function
    expect(email.value).toBe(component.emailValue);
    });
//THis returns me the value set
    expect(component.registerForm.get('email').value).toBe(component.emailValue);
  }));

Answer 1

我只是花了大约 2 个小时试图找出这个问题。根据我的经验，您需要解决 beforeEach() 函数中的一些问题。首先，您需要将 ReactiveFormsModule 导入您的 TestBed，以便 Change Detection 正确执行所有操作。其次，您需要在 beforeEach() 调用中手动运行 ngOnInit() 和 fixture.detectChanges() 来设置表单。请参阅下面的 beforeEach() 函数。我还包含了其他与此问题相关的代码。
组件模板:

<form [formGroup]='emailForm' (ngSubmit)='handleSubmit()'>
  <div class='form-group'>
    <label for='email'>Email address</label>
    <input type='email' class='form-control' id='email' placeholder='Enter email'
      formControlName='email'>

组件 TS:

  constructor(
    private apiService: ApiService,
    private fb: FormBuilder,
    private router: Router
  ) { }

  ngOnInit() {
    this.initializeForm();
  }

  initializeForm(): void {
    this.formSubmitted = false;
    this.serverProcessing = false;
    this.emailForm = this.fb.group({
      email: ['', Validators.compose([Validators.required, Validators.email])]
    });
  }

  get email() {return this.emailForm.get('email');}

Spec TS 中的两个 beforeEach() 调用:

beforeEach(
async(() => {

  apiServiceSpy = jasmine.createSpyObj('ApiService', ['sendResetPasswordEmail']);
  routerSpy = jasmine.createSpyObj('Router', ['navigateByUrl']);

  TestBed.configureTestingModule({
    declarations: [ SendPasswordResetEmailComponent ],

    // Need to import this if we're messing with Reactive Form inputs!!
    imports: [ReactiveFormsModule],

    providers: [
      {provide: ApiService, useValue: apiServiceSpy},
      {provide: Router, useValue: routerSpy},
      {provide: FormBuilder},
    ]
  })
  .compileComponents();
})
);

beforeEach(() => {
    fixture = TestBed.createComponent(SendPasswordResetEmailComponent);
    component = fixture.componentInstance;

    // ngOnInit() doesn't get called automatically, so we have to do it ourselves
    component.ngOnInit();

    // Telling the fixture to detect changes is really important to correctly bind data
    // Do this after calling ngOnInit() so changes propagate to the template 
    fixture.detectChanges();
});

sample 测试规范:

it('should have an error for no username', () => {
    const componentElement: HTMLElement = fixture.nativeElement;
    const emailInput: HTMLInputElement = componentElement.querySelector('input');
    emailInput.value = '@gmail.com';
    emailInput.dispatchEvent(new Event('input'));
    fixture.detectChanges();
    expect(component.email.errors.email).toBeTruthy('@gmail.com valid');
});

it('should have no error if the email is valid', () => {
    const componentElement: HTMLElement = fixture.nativeElement;
    const emailInput: HTMLInputElement = componentElement.querySelector('input');
    emailInput.value = 'joe@test.go';
    emailInput.dispatchEvent(new Event('input'));
    fixture.detectChanges();
    expect(component.email.errors).toBeFalsy('joe@test.go invalid');
    });