Angular2 service testing : inject a dependency with beforeEach

Question

I am testing services with an Http dependency. Every test looks like this :

import { TestBed, async, inject } from '@angular/core/testing';
import { ValidationService } from './validation.service';
import { HttpModule, Http, Response, ResponseOptions, RequestOptions, Headers, XHRBackend } from '@angular/http';
import { MockBackend, MockConnection } from '@angular/http/testing';

describe('DashboardService', () => {
  beforeEach(() => {
    TestBed.configureTestingModule({
      imports: [HttpModule],
      providers: [
        ValidationService,
        { provide: XHRBackend, useClass: MockBackend }
      ]
    });
  });

  it('should ...',
    inject([ValidationService, XHRBackend],
      (service: ValidationService, mockBackEnd: MockBackend) => {
        mockBackEnd.connections.subscribe((connection: MockConnection) => {
          connection.mockRespond(new Response(new ResponseOptions({
            body: JSON.stringify('content')
          })));
        });
      }));
      // assertions ...
});

As you can see, I need to inject the BackEnd mock at every it.

Is it possible to use a beforeEach to inject the dependency before every test ?

Paul Samsotha · Accepted Answer · 2017-04-20 13:21:22Z

49

Is it possible to use a beforeEach to inject the dependency before every test ?

Sure you could.

let service;

beforeEach(inject([Service], (svc) => {
  service = svc;
}))

Though you could also just get the service from the TestBed, which is also an injector

let service;

beforeEach(() => {
  TestBed.configureTestingModule({
    ...
  })

  service = TestBed.get(Service);
})

answered Apr 20, 2017 at 13:21

Paul Samsotha

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10 Comments

user4676340 Over a year ago

Thank you, I will try both ways to see what fits me best.

Pritesh Acharya Over a year ago

is there a way to inject Service without using TestBed setup?

Amit Chigadani Over a year ago

@PriteshAcharya See this codecraft.tv/courses/angular/unit-testing/dependency-injection

Monkey Supersonic Over a year ago

I get the error Error: StaticInjectorError[Service]: NullInjectorError: No provider for Service!

Paul Samsotha Over a year ago

@MonkeySupersonic did you configure it in the TestBed? You still need to do that.

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