如何在Jasmine/Karma中模拟角度订阅

let subscriptionMock = jasmine.createSpyObj('subscription', ['unsubscribe']);

let realSubscription = someService.subscribe();
someService.subscription = subscriptionMock;

expect(subscriptionMock.unsubscribe).toHaveBeenCalled();

describe('Example Test', () => {
  let subscriptionMock;

  beforeEach(() => {
    subscriptionMock = jasmine.createSpyObj('subscription', ['unsubscribe']);
  });

  it('should unsubscribe from the subscription', () => {
    let someService = new SomeService();
    let realSubscription = someService.subscribe();
    someService.subscription = subscriptionMock;

    // Perform some actions that trigger the unsubscribe

    expect(subscriptionMock.unsubscribe).toHaveBeenCalled();
  });
});