Angular2在单元测试中注入ElementRef [英] Angular2 Inject ElementRef in unit test

问题描述

我正在尝试测试通过DI接收对ElementRef的引用的组件.

I am trying to test a component that receives a reference to ElementRef through DI.

import { Component, OnInit, ElementRef } from '@angular/core';

@Component({
  selector: 'cp',
  templateUrl: '...',
  styleUrls: ['...']
})
export class MyComponent implements OnInit {

  constructor(private elementRef: ElementRef) {
    //stuffs
  }

  ngAfterViewInit() {
    // things
  }

  ngOnInit() {
  }
}

和测试:

import {
  beforeEach,
  beforeEachProviders,
  describe,
  expect,
  it,
  inject,
} from '@angular/core/testing';
import { ComponentFixture, TestComponentBuilder } from '@angular/compiler/testing';
import { Component, Renderer, ElementRef } from '@angular/core';
import { By } from '@angular/platform-browser';

describe('Component: My', () => {
  let builder: TestComponentBuilder;

  beforeEachProviders(() => [MyComponent]);
  beforeEach(inject([TestComponentBuilder], function (tcb: TestComponentBuilder) {
    builder = tcb;
  }));

  it('should inject the component', inject([MyComponent],
      (component: MyComponent) => {
    expect(component).toBeTruthy();
  }));

  it('should create the component', inject([], () => {
    return builder.createAsync(MyComponentTestController)
      .then((fixture: ComponentFixture<any>) => {
        let query = fixture.debugElement.query(By.directive(MyComponent));
        expect(query).toBeTruthy();
        expect(query.componentInstance).toBeTruthy();
      });
  }));
});

@Component({
  selector: 'test',
  template: `
    <cp></cp>
  `,
  directives: [MyComponent]
})
class MyTestController {
}

组件和测试蓝图均由Angular-cli生成.现在，我不知道要使用哪个提供程序(如果有的话)，我应该添加beforeEachProviders以便成功注入ElementRef.当我运行ng test时，我得到了Error: No provider for ElementRef! (MyComponent -> ElementRef).

Both the component and the test blueprint have been generated by Angular-cli. Now, I can't figure out which provider, if any, I should add in the beforeEachProviders for the injection of ElementRef to be successful. When I run ng test I got Error: No provider for ElementRef! (MyComponent -> ElementRef).

推荐答案

在Angular 2.2.3上:

On Angular 2.2.3:

export class MockElementRef extends ElementRef {}

然后在测试中:

beforeEach(async(() => {
  TestBed.configureTestingModule({
    providers: [
      //more providers
      { provide: ElementRef, useClass: MockElementRef }
    ]
  }).compileComponents();
}));

这篇关于Angular2在单元测试中注入ElementRef的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！