如何使用Angular 8中的jasmine模拟回调函数来测试promise

npm install --save-dev jasmine karma

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

describe('MyService', () => {
  let service: MyService;

  beforeEach(() => {
    TestBed.configureTestingModule({});
    service = TestBed.inject(MyService);
  });

  it('should return a resolved promise with the correct value', () => {
    const expectedValue = 'Test Value';

    // 使用Jasmine的spyOn函数来模拟回调函数
    spyOn(service, 'getData').and.returnValue(Promise.resolve(expectedValue));

    // 调用被测试的函数
    service.getData().then((result) => {
      // 断言返回的值是否与预期值相等
      expect(result).toEqual(expectedValue);
    });
  });
});