由于mock的原因，在返回可观察对象之前调用下一个可观察对象时，如何在angular/jasmine中测试可观察对象

import { of } from 'rxjs';

describe('Observable testing', () => {
  it('should test observable', () => {
    const mockValue = 'mock value';
    const observable = of(mockValue);

    observable.subscribe((value) => {
      expect(value).toEqual(mockValue);
    });
  });
});

import { of } from 'rxjs';

describe('Observable testing', () => {
  it('should test observable', (done) => {
    const mockValue = 'mock value';
    const observable = of(mockValue);

    observable.subscribe((value) => {
      expect(value).toEqual(mockValue);
      done(); // 标记测试用例结束
    });
  });
});