Question

我正在尝试测试一个取消所有订阅退订的功能：

ngOnDestroy() {
        this.tryUnsubscribe(this.carsSubscription);
        this.tryUnsubscribe(this.partsSubscription);
        this.tryUnsubscribe(this.shopsSubscription);
    }

这是我为此功能编写的测试：

it('should unsubscribe from subscriptions ', () => { 
      spyOn(component, "tryUnsubscribe");     
      component.ngOnDestroy();
      expect(component.tryUnsubscribe).toHaveBeenCalledWith(component['carsSubscription']);
      expect(component.tryUnsubscribe).toHaveBeenCalledWith(component['partsSubscription']);
      expect(component.tryUnsubscribe).toHaveBeenCalledWith(component['shopsSubscription']);
    });

问题：

如果我注释掉一个函数调用，则测试仍会通过。

ngOnDestroy() {
        this.tryUnsubscribe(this.carsSubscription);
        //this.tryUnsubscribe(this.partsSubscription);
        this.tryUnsubscribe(this.shopsSubscription);
    }

仅当我注释掉所有这些函数调用时，测试才会失败：

ngOnDestroy() {
        //this.tryUnsubscribe(this.carsSubscription);
        //this.tryUnsubscribe(this.partsSubscription);
        //this.tryUnsubscribe(this.shopsSubscription);
    }

如何正确测试这种功能？我在做什么错了？

Answer 1

我会将您的测试重写为以下内容：

it('should unsubscribe from subscriptions ', () => { 
  const spy = spyOn(component, 'tryUnsubscribe');     
  component.ngOnDestroy();

  // Check how many times the spy was called
  expect(spy).toHaveBeenCalledTimes(3);
});

如果您现在取消注释tryUnsubscribe调用中的一个，则测试将失败，因为间谍仅被调用了两次。

另一种方法是模拟订阅，或者只是将它们设置为虚拟值，以测试ngDestroy tryUnsubscribe内部是否使用了这3个组件变量：

it('test unsubscribing', () => {
  // Mock values
  component.carsSubscription = Observable.of(1).subscribe(() => {});
  component.partsSubscription = Observable.of(1).subscribe(() => {});
  component.shopsSubscription = Observable.of(1).subscribe(() => {});

  const spy = spyOn(component, 'tryUnsubscribe').and.callThrough();     
  component.ngOnDestroy();

  // Check how many times the spy was called
  expect(spy).toHaveBeenCalledTimes(3);

  // Check arguments
  expect(spy.calls.all()[0].args[0]).toEqual(component.carsSubscription);
  expect(spy.calls.all()[1].args[0]).toEqual(component.partsSubscription);
  expect(spy.calls.all()[2].args[0]).toEqual(component.shopsSubscription);
});

Here 是该测试的有效堆叠。

Answer 2

还可以使用Jasmine Calls.allArgs（）方法一次检查所有参数：

expect(spy.calls.allArgs()).toEqual([
  [component.carsSubscription],
  [component.partsSubscription],
  [component.shopsSubscription]
]);

Here修改了FabianKüng在stackblitz中的答案。

如何使用Jasmine测试多个顺序调用

2 个答案: