Angular 2 / Jasmine / Karma error: Error: Can't resolve all parameters for Router: (?, ?, ?, ?, ?, ?, ?, ?). in config/karma-shim.js

Question

这是服务：

import { Injectable } from '@angular/core';
import { Router, Event, NavigationStart, NavigationEnd, NavigationCancel, NavigationError } from '@angular/router';

@Injectable()
export class LoaderService {

  public shouldShowLoader: boolean = false;

  constructor(private router: Router) {
    router.events.subscribe((event: Event) => {
      this.navigationInterceptor(event);
    });
  }

    // Shows and hides the loading spinner during Event changes
    navigationInterceptor(event: Event): void {
        if (event instanceof NavigationStart) {
          this.shouldShowLoader = true;
        }
        else if (event instanceof NavigationEnd) {
          this.shouldShowLoader = false;
        }

        // Set loading state to false in both of the below events to hide the spinner in case a request fails
        else if (event instanceof NavigationCancel) {
          this.shouldShowLoader = false;
        }
        else if (event instanceof NavigationError) {
          this.shouldShowLoader = false;
        }
        else {
          this.shouldShowLoader = false;
        }
    }
}

这是失败的测试：

import { TestBed, inject } from '@angular/core/testing';
import { Router } from '@angular/router';
import { LoaderService } from './loader.service';

describe('LoaderServiceTest', () => {
    beforeEach(() => {
        TestBed.configureTestingModule({
            providers: [ LoaderService, Router ]
        });
    });
    
    it('#LoaderService should be defined', inject([LoaderService, Router], (service: LoaderService) => {
        expect(service).toBeDefined();
    }));

});

不确定为什么会失败？谷歌搜索类似问题，我只能找到 Angular 2 beta 的答案...我们使用的是最新的 Angular 2 / 2.2.0

Answer 1

您的测试失败，因为您没有向测试模块提供路由器需要实例化的所有参数。话虽如此，在单元测试中，不建议使用像路由器这样的服务的实际实现。更好的选择是制作这样的存根（我在这里为路由器内部的函数添加了一个间谍，以演示如果您想检查该函数是否已在某个时刻被调用将如何完成）：

class RouterStub {
    navigateByUrl = jasmine.createSpy('navigateByUrl');
}

然后在配置测试模块时：

providers: [
    ...,
    { provide: Router, useClass: RouterStub }
]

如果您想了解有关如何使用模拟和单元测试设置的更多信息，可以在此处的官方文档中找到：https://angular.io/docs/ts/latest/guide/testing.html

Angular 2 / Jasmine / Karma error: Error: Can't resolve all parameters for Router: (?, ?, ?, ?, ?, ?, ?, ?). in config/karma-shim.js

Angular 2 / Jasmine / Karma error: Error: Can't resolve all parameters for Router: (?, ?, ?, ?, ?, ?, ?, ?). in config/karma-shim.js

injectable

karma-jasmine

angular