Question

我有一个父组件：

 @Component({
selector: 'parent-component',
directives: [I18nDirective, child-component],
template: require('./parent.component.html'),
styles: [require('./parent.component.scss')],
})
export class ParentComponent {
}

然后我有子组件：

@Component({
selector: 'child-component',
template: require('./child-component.component.html'),
styles: [require('./child-component.component.scss')]
})
export class ChildComponent {

constructor(private _eventAggregator: EventAggregatorService, private _zone: NgZone) {}

在父组件的html中，我使用：child-component

问题在于子组件的规范测试。他们在考试时通过：

describe('Center On Me Button', () => {

let fixture;
let nativeElement;
let componentInstance;

beforeEachProviders(() => [
    ChildComponent,
    EventAggregatorService,
    GeoLocationService,
    provide(GoogleMapsAPIWrapper, {useClass: StabGoogleMapsApiWrapper}),
    provide(MapController, {useClass: StabMapControllerService}),
    provide(MapEventsService, {useClass: StabMapEventsService})
]);

beforeEach(injectAsync([TestComponentBuilder, GoogleMapsAPIWrapper, GeoLocationService, MapController, EventAggregatorService
    ], (tcb: TestComponentBuilder ) => {

    return tcb
        .createAsync(ChildComponent).then((componentFixture: ComponentFixture<ChildComponent>) => {

            ({nativeElement, componentInstance} = componentFixture);
            fixture = componentFixture;
            componentFixture.detectChanges();
        });

 it('should enable Geolocation button when it is clicked', done => {
    componentInstance.isGeoLocationButtonEnabled = false;
    nativeElement.querySelector('.toggle.fa.fa-crosshairs').click();
    expect(componentInstance.isGeoLocationButtonEnabled).toBe(true);
    done();
});
}));

我的问题是在这样的配置中测试通过了。但是，只要我想将服务实例添加到子组件构造函数中，测试就不会通过（在parent.component.spec中失败），并显示以下消息：

 TypeError: undefined is not an object (evaluating 'fixture.detectChanges') ... in parent.component.spec.ts

我所做的就是添加： private someService：SomeService到子组件的构造函数。所以我现在有：

export class ChildComponent {

constructor(private _eventAggregator: EventAggregatorService, private _zone: NgZone, private _someService: SomeService) {}

我添加的这项服务被添加到角度应用程序顶层的提供者列表中。当然，我将它添加到测试本身的提供者列表中。

当我这样做时，测试开始失败，我写的上一条消息。为什么这样呢？我真的不明白这种行为，资源在网络中受到限制。还没有文档。

当我向构造函数添加服务时，Fixture.detectChanges以一种奇怪的方式运行

0 个答案: