Question

我有一个组件：

export class StopwatchComponent implements OnInit {
  hours = '00';
  minutes = '00';
  seconds = '00';
  isPaused = true;
  isStarted = true;
  num = 0;
  @ViewChild('waitBtn', {read: ElementRef}) waitBtn: ElementRef;

  stopTimer() {
    (this.hours = '00'), (this.minutes = '00'), (this.seconds = '00');
    this.num = 0;
    this.timerService.stop();
    this.isStarted = true;
    this.isPaused = true;
    this.timer.unsubscribe();
  }
}

并为stopTimer()函数编写了一些测试，但是当我运行具有覆盖率的测试时，它们根本不会覆盖它，并且也不会损坏这是我的代码：

it('should create', () => {
    expect(component).toBeTruthy();
  });

  it(`should create all parameters`, () => {          //works
    const fixture = TestBed.createComponent(StopwatchComponent);
    const header = fixture.componentInstance;
    expect(header.hours).toEqual('00');
    expect(header.minutes).toEqual('00');
    expect(header.seconds).toEqual('00');
    expect(header.isPaused).toEqual(true);
    expect(header.isStarted).toEqual(true);
    expect(header.num).toEqual(0);
    fixture.debugElement.query(By.css('#waitBtn'));
  });

 it('should call stopTimer', () => {          //don't
    const mockSpyStopTimer = spyOn(component, 'stopTimer');
    fixture.detectChanges();
    component.stopTimer();
    expect(component.hours).toEqual('00');
    expect(component.minutes).toEqual('00');
    expect(component.seconds).toEqual('00');
    expect(component.num).toEqual(0);
    expect(component.isStarted).toBeTruthy();
    expect(component.isPaused).toBeTruthy();
    expect(mockSpyStopTimer).toHaveBeenCalled();
  });

Answer 1

之所以没有涵盖它，是因为当您spyOn使用一种方法时，您会丢失其实现详细信息，而只是获得一个“ API”，您可以在其中查看是否调用了该方法。要不丢失实施细节，请使用.and.callThrough()。

it('should call stopTimer', () => { 
    // now every time stopTimer is called, we have its original implementation details         
    const mockSpyStopTimer = spyOn(component, 'stopTimer').and.callThrough(); // change this line
    fixture.detectChanges();
    component.stopTimer();
    expect(component.hours).toEqual('00');
    expect(component.minutes).toEqual('00');
    expect(component.seconds).toEqual('00');
    expect(component.num).toEqual(0);
    expect(component.isStarted).toBeTruthy();
    expect(component.isPaused).toBeTruthy();
    expect(mockSpyStopTimer).toHaveBeenCalled();
  });

单元测试根本不涵盖代码（业力）

1 个答案: