Angular 5 service failing to pass unit tests with (NullInjectorError: No provider for HttpClient!)

Question

I keep getting the following errors when running unit tests

Error: StaticInjectorError(DynamicTestModule)[ApiService -> HttpClient]: 
      StaticInjectorErro         


        

Answer 1

Try wrapping your inject in an async, like below:

import { TestBed, async, inject } from '@angular/core/testing';
import { HttpClientTestingModule, HttpTestingController } from '@angular/common/http/testing';
import { ApiService } from './api.service';

describe('ApiService', () => {
    beforeEach(() => {
      ...
    });    

  it(`should create`, async(inject([HttpTestingController, ApiService],
    (httpClient: HttpTestingController, apiService: ApiService) => {
      expect(apiService).toBeTruthy();
  })));

});

Don't forget to import async from @angular/core/testing.

I have had good success with this. It's the only different from your unit tests and mine where I use HttpClientTestingModule.