如何在Jasmine单元测试中订阅Observable？

import { Observable } from 'rxjs';
import { of } from 'rxjs';
import { Subscription } from 'rxjs';

describe('Observable Subscription', () => {
  it('should subscribe to an Observable', () => {
    // 在这里编写测试逻辑
  });
});

it('should subscribe to an Observable', () => {
  const observable = of('Hello, World!'); // 创建一个Observable对象
  const subscription = observable.subscribe((value) => {
    expect(value).toBe('Hello, World!'); // 断言接收到的值是否符合预期
  });

  expect(subscription instanceof Subscription).toBe(true); // 断言subscription是Subscription的实例

  subscription.unsubscribe(); // 取消订阅，确保在测试结束后清理资源
});