Angular 9 - Error: StaticInjectorError[Http]: StaticInjectorError[Http]: NullInjectorError: No provider for Http

Question

I'm new in Angular testing. Now I am trying to test services. When I run ng test for my unit tests, and when those tests use the service, I am getting the error:

Error: StaticInjectorError[Http]:  
StaticInjectorError[Http]: 
NullInjectorError: No provider for Http!

Here is my spec file:

import { TestBed, inject } from "@angular/core/testing";
import { ContactService } from "./contact.service";
import { HttpClientTestingModule, HttpTestingController } from '@angular/common/http/testing';
import {HttpClientModule} from '@angular/common/http';

describe("ContactService", () => {
  beforeEach(() => {
    TestBed.configureTestingModule({
        imports: [HttpClientTestingModule, HttpClientModule], 
        providers: [ContactService],
    });
  });
  
  it("should ...", inject([ContactService], (service: ContactService) => {
    expect(service).toBeTruthy();
  }));
});

And this is my .sevice.ts file imports:

import { Headers, Http } from '@angular/http';
import 'rxjs/add/operator/toPromise';
import { Contact } from '../';

Answer 1

You are injecting http module from @angular/common but you have imported @angular/http module.

Change to this:

import { Headers, Http } from '@angular/common/http';

and you just need this:

imports: [HttpClientTestingModule], 

or instead of actual ContactService you can mock it:

class MockContactService {
   // properties and methods to mock
}

now you can use this within your provider:

providers: [
   {
     provide: ContactService,
     useClass: MockContactService
   }
]