Angular 6-NullInjectorError：在单元测试中没有HttpClient的提供程序

Question

我正在导入和HttpClient在服务中使用，如下所示：

import { Injectable } from '@angular/core';
import { HttpClient } from '@angular/common/http';

@Injectable({
    providedIn: 'root',
})
export class MyService {
    constructor(private http: HttpClient) { }

    getData() {
        return this.http.get("url...");
    }
}

但是，当我ng test为单元测试运行时，以及那些测试使用该服务时，出现了以下错误：

Error: StaticInjectorError(DynamicTestModule)[HttpClient]: StaticInjectorError(Platform: core)[HttpClient]: NullInjectorError: No provider for HttpClient!

HTTP上的Angular 6文档只是说了做我上面的事情。

Answer 1

import { TestBed } from '@angular/core/testing';
import { HttpClientTestingModule, HttpTestingController } from '@angular/common/http/testing';
import {HttpClientModule} from '@angular/common/http';
import { myService } from './myservice';


describe('myService', () => {

      beforeEach(() => TestBed.configureTestingModule({
        imports: [HttpClientTestingModule], 
        providers: [myService]
      }));

       it('should be created', () => {
        const service: myService = TestBed.get(myService);
        expect(service).toBeTruthy();
       });

       it('should have getData function', () => {
        const service: myService = TestBed.get(myService);
        expect(service.getData).toBeTruthy();
       });

    });