angular - 测试依赖于服务的管道

Question

我有一个 sanatises HTML 的管道，如下所示:

import { Pipe, PipeTransform } from '@angular/core';
import { DomSanitizer } from '@angular/platform-browser';

@Pipe({
    name: 'sanitiseHtml'
})

export class SanitiseHtmlPipe implements PipeTransform {

constructor(private _sanitizer: DomSanitizer) {}

    transform(value: any): any {
      return this._sanitizer.bypassSecurityTrustHtml(value);
    }

}

我想测试如下:

describe('Pipe: Sanatiser', () => {
    let pipe: SanitiseHtmlPipe;

    beforeEach(() => {
        pipe = new SanitiseHtmlPipe(new DomSanitizer());
    });

    it('create an instance', () => {
        expect(pipe).toBeTruthy();
    }); 
});

DomSanatizer 是一个抽象类，通过将其传递给构造函数由 typescript Autowiring :

constructor(private _sanitizer: DomSanitizer) {}

目前我得到 typescript 错误:

Cannot create an instance of the abstract class 'DomSanitizer'.

有谁知道在 Angular 中实例化传递给构造函数的依赖项时 typescript 会做什么？或者测试这样的东西的方法是什么？

Answer 1

由于你管道中的DI，你需要配置一个测试环境(test bed)来解决依赖:

import { BrowserModule, DomSanitizer } from '@angular/platform-browser';
import { inject, TestBed } from '@angular/core/testing';

describe('SanitiseHtmlPipe', () => {
  beforeEach(() => {
    TestBed
      .configureTestingModule({
        imports: [
          BrowserModule
        ]
      });
  });

  it('create an instance', inject([DomSanitizer], (domSanitizer: DomSanitizer) => {
    let pipe = new SanitiseHtmlPipe(domSanitizer);
    expect(pipe).toBeTruthy();
  })); 
});