RouterTestingModule 不提供 Location 的提供者

Question

我正在对使用另外两个组件的 Component 进行单元测试。单击按钮时会创建其他组件

.html

    <div id="homepage-top-div" class="homepage-component-css-grid-container">  ...
        <button id="get-question-list-button" [routerLink]="questionListRouterLink" class="btn content-div__button--blue css-grid-item-button-div btn-sm">See Questions</button>
      </div>
      <div id="practice-component-top-div" class="css-grid-container-div common-styles-div--white"> <!-- 4 rows, 1 column-->
...
        <button id="new-question-button" [routerLink]="newQuestionRouterLink"  class="btn content-div__button--blue css-grid-item-button-div btn-sm">Create a Question</button>
      </div>
    </div>

.ts

export class HomepageContentComponentComponent implements OnInit {

  public questionListRouterLink="/practice-question-list";
  public newQuestionRouterLink="/new-practice-question";


  constructor() {

  }

  ngOnInit() {
  }

}

我创建了一个规范，但是当我运行它时出现以下错误 - Error: StaticInjectorError[Location]: NullInjectorError: No provider for Location!

规格是

import {async, ComponentFixture, fakeAsync, TestBed, tick} from '@angular/core/testing';
import { HomepageContentComponentComponent } from './homepage-content-component.component';
import {RouterTestingModule} from "@angular/router/testing";
import {AppRoutingModule} from "../app-routing.module";
import {Router} from "@angular/router";
import {routes} from '../app-routing.module';
import {NewPracticeQuestionComponent} from "../new-practice-question/new-practice-question.component";
import {PraticeQuestionListComponent} from "../pratice-question-list/pratice-question-list.component";
import {NgModule} from "@angular/core";
import {AppModule} from "../app.module";

fdescribe('HomepageContentComponentComponent', () => {
  let component: HomepageContentComponentComponent;
  let fixture: ComponentFixture<HomepageContentComponentComponent>;

  beforeEach(async(() => {
    TestBed.configureTestingModule({
      imports:[
        AppModule,
        AppRoutingModule,
        RouterTestingModule.withRoutes(routes) //<-- I SUPPOSE THIS STEP SHOULD PROVIDE ROUTERTESTINGMODULE WITH PROVIDERS FOR LOCATION BUT IT SEEMS IT ISN'T
      ],
      declarations: [ HomepageContentComponentComponent,
                  NewPracticeQuestionComponent,
        PraticeQuestionListComponent]
    })
    .compileComponents();
  }));

  beforeEach(() => {
    fixture = TestBed.createComponent(HomepageContentComponentComponent);
    component = fixture.componentInstance;
    fixture.detectChanges();
  });

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

  it('should navigate to New Questions Component when New Question button is clicked',fakeAsync(()=>{
    let router:Router;
    let location:Location;
    router = TestBed.get(Router);
    location = TestBed.get(Location);
    console.log('initial router is ',router);
    console.log('initial location is ',location);
    router.initialNavigation();
    router.navigate(['new-practice-question']);
    tick();
    console.log('new router is ',router);
    console.log('new location is ',location);

    expect(location.pathname).toBe('/new-practice-question');
  }));
});

Answer 1

早些时候，我通过显式添加提供程序使代码工作。但我认为情况不应该如此。我不确定为什么只使用 RouterTestingModule 不起作用。

解决方法

providers:[...,
{provide: Location, useClass: SpyLocation},
        {provide: LocationStrategy, useClass: MockLocationStrategy},
        {provide: NgModuleFactoryLoader, useClass: SpyNgModuleFactoryLoader}]

实际问题是由于未知原因选择了错误的 Location 定义。当我添加 import {Location} from "@angular/common";

时，测试没有明确添加 providers

Answer 2

之所以选择了错误的 Location 以及为什么 import {Location} from "@angular/common"; 有所帮助，是因为在不导入它的情况下，TypeScript 实际上认为您想要使用 window.location 的类型，这与你要找的那个。

由于类型是从 angular 的 DI 注册表中检索所需实例的标记，因此如果您使用错误的类型，您将得不到任何东西。当您在 IDE 中注释掉导入和 'click through' Location 类型时，您会看到选择的类型实际上是 DOM 接口，而不是 Angular 执行。一旦你的 tsconfig.json 中有 "lib": ["dom"]，这个 DOM 接口就隐含在那里。

从 angular 导入 Location 显式地从 DOM 中导入 Location，选择正确的类型并在 [= 中找到正确的 Location 实例31=] 的 DI 注册表。

实际上很容易犯错误（我自己犯的），因为即使你忘记导入 Location，DOM Location 也会被选中，你会得到IDE 中完全没有反馈，您会想知道为什么 DI 会失败。

RouterTestingModule 不提供 Location 的提供者

RouterTestingModule not providing provider for Location

angular

angular6

angular-routing

angular-test