Question

我正在尝试为位于build hint的此组件添加单元测试.... 但是我收到一个错误，因为该组件与类型有依赖关系：＆＃34; IterableDiffers＆＃34;

export class DualListComponent implements DoCheck, OnChanges { ....
constructor(private differs: IterableDiffers) {} ...

我的第一次尝试就像这样：

＆＃13;

import { async, ComponentFixture, TestBed} from '@angular/core/testing';

import { By } from '@angular/platform-browser';
import { DebugElement } from '@angular/core';
import { TranslateModule } from 'ng2-translate/ng2-translate';
import { DualListComponent } from './dual-list.component';

describe('DashboardHeroComponent when tested directly', () => {

    let comp: DualListComponent;
    let fixture: ComponentFixture<DualListComponent>;
    let heroEl: DebugElement;

    // async beforeEach
    beforeEach(async(() => {
        TestBed.configureTestingModule({
            declarations: [DualListComponent],
            imports: [ TranslateModule.forRoot()]
        })
            .compileComponents(); // compile template and css
    }));

    // synchronous beforeEach
    beforeEach(() => {

        let srouce: Array < any > = [
            { key: 1, station: 'Antonito', state: 'CO' },
            { key: 2, station: 'Big Horn', state: 'NM' },
            { key: 3, station: 'Sublette', state: 'NM' },
            { key: 32, station: 'Eureka', state: 'CO' }
        ];
        fixture = TestBed.createComponent(DualListComponent);
        comp = fixture.componentInstance;
        heroEl = fixture.debugElement.query(By.css('.hero')); // find hero element

        comp.key = 'key';
        comp.display = 'station';
        comp.source = srouce;
        comp.destination = [];
        fixture.detectChanges(); // trigger initial data binding
    });

    it('should display hero name', () => {
        expect(comp.available.list.length).toEqual(4);
    });
});

＆＃13;

运行后我得到的错误;＆＃34; npm test＆＃34;是：

TypeError: Cannot read property 'diff' of undefined

错误信息本身并不太清楚，但原因是因为尝试使用对象＆＃34;不同＆＃34;什么应该在构造函数中加载。

任何想法如何在测试中添加它？

更新1 按照Tiep Phan的说明并插入＆＃34; IterableDiffers＆＃34;作为提供者......我遇到了问题：＆＃34;无法解决IterableDiffers的所有参数＆＃34; ... 我可以理解错误，但不知道如何解决它...错误主要是因为IterableDiffers类的构造函数接受类型＆＃34; IterableDifferFactory＆＃34;的数组。

constructor(factories: IterableDifferFactory[]);

如何注入IterableDiffers＆＃34; service＆＃34;进入单元测试

0 个答案: