如何模拟 angular2 平台浏览器标题组件以进行测试

Question

我正在使用 Jasmine 为 Angular 2 组件编写单元测试。当我的组件被实例化时，我想测试我的文档标题是否设置为特定值。

这是我的组件

import { Component } from '@angular/core';
import { Title }     from '@angular/platform-browser';

@Component({
  selector: 'cx-account',
  templateUrl: 'app/account/account.component.html',
})
export class AccountComponent {
  public constructor(private titleService: Title ) {
    titleService.setTitle("Account");
  }
}

这是我为测试而编写的，但它不起作用。 titleService.getTitle() 给了我 Karma 调试运行器页面标题。

import { TestBed }      from '@angular/core/testing';
import { Title, By }           from '@angular/platform-browser';
import { AccountComponent } from './account.component';

describe('AppComponent Tests', function () {
  let titleService: Title = new Title(); 
  beforeEach(() => {
    TestBed.configureTestingModule({
        declarations: [AccountComponent],
        providers:    [ {provide: Title } ],      
    });
   let fixture = TestBed.createComponent(AccountComponent);

   });

  it('Title Should be Account', () => {
    expect(titleService.getTitle()).toBe('Account');
  });      
});

业力输出是：

错误：“Karma DEBUG RUNNER”应为“帐户”。

Answer 1

我终于找到了解决问题的方法。我使用 TestBed 来获取我注入的服务。然后使用该服务获取当前测试上下文中的页面标题。 这是我的新代码

import {  TestBed }      from '@angular/core/testing';
import { Title}           from '@angular/platform-browser';
import { AccountComponent } from './account.component';

describe('AccountComponent Tests', function () {
    let userService: Title;
    let fixture: any;
    let comp: AccountComponent;
    beforeEach(async(() => {
        TestBed.configureTestingModule({
            declarations: [AccountComponent],
            providers: [{ provide: Title, useClass: Title }],
        }).compileComponents();
    }));

    beforeEach(() => {
        fixture = TestBed.createComponent(AccountComponent);
        // Access the dependency injected component instance
        comp = fixture.componentInstance;
    });

    it('Page title Should be Account', () => {
            userService = TestBed.get(Title);
            expect(userService.getTitle()).toBe("Account");
    });
    it('should instantiate component', () => {
            expect(comp instanceof AccountComponent).toBe(true, 'should create AccountComponent');
    });


});