业力-ChangeDetectorRef detectChanges模拟 [英] Karma - ChangeDetectorRef detectChanges mocking

问题描述

我的测试中cdr.detectChanges()有问题.调用它时发生错误，我没有任何信息，我只收到此错误:

I have an issue with cdr.detectChanges() in my test. I have an error happening when it's called and I don't have any information, I just get this error :

ZoneAwareError @ webpack:///~/zone.js/dist/zone.js:923:0<- config/karma-shim.js:108645:28 invokeTask @ webpack:///~/zone.js/dist/zone.js:398:0<-config/karma-shim.js:108120:36 onInvokeTask @ webpack:///~/zone.js/dist/proxy.js:103:0<-config/karma-shim.js:107642:49

ZoneAwareError@webpack:///~/zone.js/dist/zone.js:923:0 <- config/karma-shim.js:108645:28 invokeTask@webpack:///~/zone.js/dist/zone.js:398:0 <- config/karma-shim.js:108120:36 onInvokeTask@webpack:///~/zone.js/dist/proxy.js:103:0 <- config/karma-shim.js:107642:49

有没有办法使detectChanges起作用?

Is there a way to make detectChanges work?

我还尝试通过在我的测试组件配置中定义cdr来使detectChanges什么都不做来尝试其他事情:

I also tried something else by trying to make detectChanges do nothing by defining cdr in my test component configuration like this :

cdr = {
  detectChanges: () => {}
}

，然后在提供程序{ provide: ChangeDetectorRef, useValue: cdr }中，但是当我在console.info中测试了方法中的cdr时，似乎我仍然拥有原始的cdr类.

and then in the providers { provide: ChangeDetectorRef, useValue: cdr }, but when I console.info the cdr in the method tested it seems I still have the original cdr class.

我还尝试了一个伪类定义如下:

I also tried with a fake class defined like this :

class FakeCDR {
  detectChanges(): void {

  }
}

，然后在提供程序中单击{ provide: ChangeDetectorRef, useClass: FakeCDR }，但在此处相同.

and then { provide: ChangeDetectorRef, useClass: FakeCDR } in the providers, but same here.

这是我的测试代码:

it('should create an user', fakeAsync(inject([MockBackend],
  (backend: MockBackend) => {
    fixture.detectChanges()
    tick()

    component.newUser = User.newUserDraft()
    component.newUser.email = "[e-mail]"
    component.createUser()
    tick()

    expect(component.newUser.email).toBe(User.newUserDraft().email)
  })))

并在createUser中执行一项服务.createUser然后执行一些操作，然后执行cdr.detectChanges().我确实把console.info放在每一行，所以我确定它是在detectChanges上失败了.

and in createUser it's doing a service.createUser then do some stuff then cdr.detectChanges(). I did put console.info at every lines so I'm sure it's at the detectChanges that it fails.

推荐答案

首先要考虑的事项:

1. ChangeDetectorRef不是通过DI提供的，因此您不能提供双精度数.
2. fixture.changeDetectorRef与提供的组件不同，因此您不能使用它.
3. fixture.debugElement.injector.get(ChangeDetectorRef)将创建私有类ViewRef的新实例(公共类ViewRef只是ViewRef$1的别名)，每次调用时，提供给组件的对象是另一个

1. ChangeDetectorRef is not provided through DI, so you cannot provide a double.
2. fixture.changeDetectorRef is not the same as the component provided, so you cannot use this.
3. fixture.debugElement.injector.get(ChangeDetectorRef) will create a new instance of the private class ViewRef (the public class ViewRef is just an alias for ViewRef$1), every time it is invoked, then the object provided to the component is another.

所以我的解决方法是:

const changeDetectorRef = fixture.debugElement.injector.get(ChangeDetectorRef);
const detectChangesSpy = spyOn(changeDetectorRef.constructor.prototype, 'detectChanges');

这篇关于业力-ChangeDetectorRef detectChanges模拟的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！