在单元测试Angular 4组件时,我陷入困境并继续出错。
这是我的组成部分:
阶detail.component.ts
@Component({
selector: 'order-detail',
templateUrl: 'order-detail.component.html',
providers: [OrderService]
})
export class OrderDetailComponent implements OnInit {
private order: Order;
constructor(
private orderService: OrderService,
private route: ActivatedRoute,
private router: Router
) {}
ngOnInit() {
this.getOrder();
}
private getOrder(): void {
this.route.paramMap
.map((params: ParamMap) => {
if (+params.get('id') === 0) {
this.router.navigateByUrl('/404', {skipLocationChange: true});
}
return params;
})
.switchMap((params: ParamMap) => this.orderService.getOrder(+params.get('id')))
.subscribe((order: Order) => this.order = order);
}
}
这是一项服务:
order.service.ts
@Injectable()
export class OrderService {
private ordersUrl = `${environment.apiUrl}/orders/`;
constructor(private http: HttpClient) {}
getOrder(id: number): Observable<Order> {
return this.http.get(`${this.ordersUrl}${id}/`)
.map(response => response as Order);
}
}
我想在OrderServive
上设置间谍,然后用这样的测试进行单元测试:
阶detail.component.spec.ts
describe('Order detail component', () => {
let fixture: ComponentFixture<OrderDetailComponent>;
let page: Page;
let activatedRoute: ActivatedRouteStub;
const fakeOrder: Order = {
id: 1,
title: 'Test 1',
contractor: {title: 'Contractor 1'} as Contractor,
} as Order;
class Page {
orderSpy: jasmine.Spy;
routerSpy: jasmine.Spy;
title: HTMLElement;
constructor() {
const orderService = fixture.debugElement.injector.get(OrderService);
this.orderSpy = spyOn(orderService, 'getOrder').and.returnValue(Observable.of(fakeOrder));
}
}
function createComponent() {
fixture = TestBed.createComponent(OrderDetailComponent);
page = new Page();
fixture.detectChanges();
return fixture.whenStable().then(() => {
fixture.detectChanges();
});
}
beforeEach(() => {
activatedRoute = new ActivatedRouteStub();
});
beforeEach(async(() => {
TestBed.configureTestingModule({
declarations: [OrderDetailComponent],
imports: [RouterTestingModule, HttpClientTestingModule],
providers: [
OrderService,
{provide: ActivatedRoute, useValue: activatedRoute},
{provide: Router, useClass: RouterStub},
],
schemas: [NO_ERRORS_SCHEMA],
}).compileComponents();
}));
describe('when navigate with existing id', () => {
beforeEach(async(() => {
activatedRoute.testParamMap = {id: fakeOrder.id};
createComponent();
}));
it('should show title', () => {
expect(page.orderSpy).toHaveBeenCalledWith(fakeOrder.id);
});
});
});
但我一直收到此错误:TypeError: Cannot read property 'subscribe' of undefined
我从Agular文档中获取ActivatedRouteStub
并测试结构:https://angular.io/guide/testing
组件代码可以很好地处理来自后端的实际数据,并向我显示订单。
此外,我的代码库包含类似的测试,它在具有类似服务的另一个组件上成功地执行相同的操作,因此该测试是唯一失败的地方。
使用Angular 4.3.6,Karma 1.7.1和Jasmine 2.6.4。
可能出现什么问题以及如何摆脱这个错误?
答案 0 :(得分:3)
经过一些研究,我实际上发现了导致错误的原因。我删除了
{provide: Router, useClass: RouterStub},
并且错误消失了。如果没有这个存根,测试现在可以正常工作。
不确定是什么问题,但我认为来自docs的RouterStub
类缺少某些必要事项的实现。上课是从这里取的:
https://angular.io/guide/testing#test-a-routed-component
https://angular.io/generated/live-examples/testing/app-specs.eplnkr.html