JASMINE：监视scrollIntoView抛出错误

Question

spyon函数抛出错误，提示Expected spy scrollIntoView to have been called

下面是我的component的代码片段：

@Component({
  template: `
    <form appFocusFirstInvalidField>
      <input type="text" class="ng-invalid" onFocus>
      <button type="submit"></button>
    </form>
    `
})
class FocusFirstInvalidInputComponent {
  constructor(private el: ElementRef) {
    console.log('in constructor');
  }
}

下面是测试用例，这里我为输入元素添加了spyon函数，但是抛出了错误。

describe('Directive: onFocus', () => {
  let fixture: ComponentFixture<FocusFirstInvalidInputComponent>;
  let inputEl: HTMLElement;
  beforeEach(() => {
    TestBed.configureTestingModule({
      declarations: [FocusFirstInvalidInputComponent, FocusFirstInvalidFieldDirective]
    });
    fixture = TestBed.createComponent(FocusFirstInvalidInputComponent);
    inputEl = fixture.nativeElement.querySelector('input');
  });
  it('restrict should paste', () => {
    fixture.detectChanges();
    const event = new Event('submit', { bubbles: true });
    spyOn(inputEl, 'scrollIntoView');
    inputEl.dispatchEvent(event);
    expect(inputEl.scrollIntoView).toHaveBeenCalled();
  });
}); ```