Test pipe with dependencies on services

Question

I have a pipe that sanatises HTML as below:

import { Pipe, PipeTransform } from \'@angular/core\';
import { DomSanitizer } from \'@angular/platform-browser\';

@         


        

Answer 1

In case you want to mock the whole providers and don't wanna use the constructor, this is how I do it (with Jest but replace the spy with your regular jasmine.createSpyObj)

spec

describe("MyPipe", () => {
  let pipe: MyPipe;
  const myServiceSpy = { myFunction: jest.fn() };

  beforeEach(() => {
    jest.clearAllMocks();
    TestBed.configureTestingModule({
      providers: [
        MyPipe,
        {
          provide: MyService,
          useValue: myServiceSpy
        }
      ]
    });

    pipe = TestBed.inject(myPipe);
  });

  it("create an instance", () => {
    expect(pipe).toBeTruthy();
  });
});

pipe

@Pipe({
  name: "myPipe"
})
export class MyPipe implements PipeTransform {
  constructor(private readonly myService: MyService) {}

  transform(value: Item): boolean {
    // stuff with your service
    return true;
  }
}