在ngOnInt进行远程调用的单元测试

import { ComponentFixture, TestBed } from '@angular/core/testing';
import { MyComponent } from './my.component';
import { MyService } from './my.service';
import { HttpClientTestingModule } from '@angular/common/http/testing';

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

  beforeEach(async () => {
    await TestBed.configureTestingModule({
      declarations: [MyComponent],
      imports: [HttpClientTestingModule],
      providers: [MyService]
    }).compileComponents();
  });

  beforeEach(() => {
    fixture = TestBed.createComponent(MyComponent);
    component = fixture.componentInstance;
    myService = TestBed.inject(MyService);
    fixture.detectChanges();
  });

  it('should call remote service on ngOnInit', () => {
    spyOn(myService, 'remoteCall').and.returnValue(Promise.resolve('mocked data'));

    component.ngOnInit();

    expect(myService.remoteCall).toHaveBeenCalled();
    expect(component.data).toBe('mocked data');
  });
});