使用服务调用的角度测试ngOnInit

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

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

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

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

  it('should initialize component', () => {
    // Define mock data
    const mockData = { id: 1, name: 'Test' };

    // Set up mock service method
    spyOn(myService, 'getData').and.returnValue(mockData);

    // Call ngOnInit
    component.ngOnInit();

    // Verify component properties and service calls
    expect(component.data).toEqual(mockData);
    expect(myService.getData).toHaveBeenCalled();
  });
});