Angular Testing provider useValue for environment throws NullInjectionError

Question

I have a provider for environment in our Angular application and we have it like this:

{ provide: 'environment', useValue: environment }

Alongside this we have a lot of other providers as services as well. Now this works fine in the application but when I run ng test it throws an error for any service that uses it.

NullInjectorError: No provider for environment

@Inject('environment') environment: Environment

How do I progress on this since I need the environment to be injected automatically as well.

Answer 1

1. Create a new file testing.module.ts in your project:

import { NgModule } from '@angular/core';
import { environment } from '../environments/environment';

@NgModule({
  providers: [
    { provide: 'environment', useValue: environment }
  ]
})
export class TestingModule { }

2. Import TestingModule in your test files:

import { TestingModule } from './testing.module';

describe('MyService', () => {
  beforeEach(() => TestBed.configureTestingModule({
    imports: [ TestingModule ],
    // other configuration
  }));

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