在Angular中测试AsyncValidators -测试通过，但不确定expect语句是否正在运行/执行

import { TestBed, ComponentFixture, async } from '@angular/core/testing';
import { FormControl, FormGroup, Validators } from '@angular/forms';
import { MyAsyncValidator } from './my-async-validator'; // 假设这是你的AsyncValidator

describe('MyAsyncValidator', () => {
  let component: MyComponent;
  let fixture: ComponentFixture<MyComponent>;

  beforeEach(async(() => {
    TestBed.configureTestingModule({
      declarations: [MyComponent],
    }).compileComponents();
  }));

  beforeEach(() => {
    fixture = TestBed.createComponent(MyComponent);
    component = fixture.componentInstance;
    component.form = new FormGroup({
      myControl: new FormControl('', null, MyAsyncValidator.validate),
    });
    fixture.detectChanges();
  });

  it('should run expect statement', async(() => {
    component.form.controls['myControl'].setValue('test value');
    fixture.detectChanges();

    // 在这里编写你的expect语句，例如：
    expect(component.form.controls['myControl'].valid).toBeTruthy();
  }));
});