在Angular 2中测试服务时，NgModule'DynamicTestModule'的提供程序无效 [英] Invalid provider for the NgModule 'DynamicTestModule' when testing a service in Angular 2

问题描述

我有以下服务:

import { Injectable } from '@angular/core';

import { MenuItem } from './../classes/menu-item';
import { ITEMS } from './../static-data/items-list';

@Injectable()
export class ItemsListService {

    getItems(): Promise<MenuItem[]> {
        return Promise.resolve(ITEMS);
    }

}

此服务的测试在这里:

import { TestBed, async, inject } from '@angular/core/testing';

import { ItemListService } from './item-list.service';
import { MenuItem } from './../classes/menu-item';
import { ITEMS } from './../static-data/items-list';

describe('ItemListService', () => {
  beforeEach(() => {
    TestBed.configureTestingModule({
        providers: [ ItemListService, MenuItem, ITEMS ]
    });
  });

  it('should ...', inject([ItemListService], (service: ItemListService) => {
    expect(service).toBeTruthy();
  }));
});

在此处定义MenuItem:

The MenuItem is defined here:

export class MenuItem {
    name: string;
    link: string;
}

ITEMS在这里定义: 从'./../classes/menu-item'导入{MenuItem};

ITEMS is defined here: import { MenuItem } from './../classes/menu-item';

export var ITEMS: MenuItem[] = [
    {name: 'Vehicles', link: '/vehicles'},
    {name: 'Gateways', link: '/gateways'},
    {name: 'Statuses', link: '/statuses'},
    {name: 'Logs', link: '/logs'}
]

运行测试时，我在浏览器控制台中遇到以下错误:

When I run the test I am getting in the browsers console the followings errors:

FAILED ItemListService should ...

和

那么为什么会有这些错误?这项测试有效的解决方案是什么?

So why do I have these errors? And what is the solution for the test to work?

推荐答案

这是一个令人讨厌的错误，以为我会在您的规范中寻找另一个细微的原因.在我的情况下，我指定了"provider"而不是如下的"provide"

This is such an annoying error, thought I'd include another subtle cause to look for in your spec. In my case I specified 'provider' instead of 'provide' as below

 TestBed.configureTestingModule({
      providers: [{provider: ApplicationActions, useClass: ActionMock}] // don't do that (missing 'provide')!

它不会报告诸如提供未指定'提供'密钥"之类的有用信息，而是会报告

rather than offer useful information like "no 'provide' key specified" it simply reports

失败:NgModule'DynamicTestModule'的提供程序无效-仅 Provider和Type的实例被允许，得到:[?[object Object] ?, ...]

Failed: Invalid provider for the NgModule 'DynamicTestModule' - only instances of Provider and Type are allowed, got: [?[object Object]?, ...]

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