Angular 2 unit test case using Function not provider

Question

I am using a function in my actual service but I want to know how can i inject that function in unit test case. Below isSameDay is a function not provider. How can i inject it into test case as this function is working fine in actual service.

import { LoggerService, isSameDay } from '../../../shared';

describe('NavBaseComponent', () => {
  let component: NavBaseComponent;
  let fixture: ComponentFixture<NavBaseComponent>;

  beforeEach(() => {
    TestBed.configureTestingModule({
      declarations: [NavBaseComponent],
      providers: [
        LoggerService
      ]
    })
      .compileComponents();
  });

  beforeEach(() => {
    fixture = TestBed.createComponent(NavBaseComponent);
    component = fixture.componentInstance;
    fixture.detectChanges();
  });

  it('should be created', () => {
    expect(component).toBeTruthy();
  });
});

Code for isSameDay function

export function isSameDay(d1: Date, d2: Date): boolean {
    return !!d1 && !!d2 &&
        d1.getDate() === d2.getDate() && 
        d1.getMonth() === d2.getMonth() &&
        d1.getFullYear() === d2.getFullYear();
};

Can you add the shared code? Is it a method inside provider or something else? — eko
– eko, Commented Nov 16, 2017 at 11:21

eko · Accepted Answer · 2017-11-16 13:06:35Z

4

+50

You don't need to inject it anywhere, you can test it as is.

import { LoggerService, isSameDay } from '../../../shared';

describe..

  it('should test isSameDay', ()=>{
      expect(isSameDay(new Date(), new Date())).toEqual(true);
  })

..

Here's a plunker example: http://plnkr.co/edit/TyTyaJvDD28AqPH2yDKa?p=preview

answered Nov 16, 2017 at 13:06

eko

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4 Comments

Rohit Over a year ago

I don't want to test isSameDay. It's is used inside map(date=> isSameDay(date, new Date())). It is creating issue while test case is running error : isSameDay is not a function. Test case is not aware of this function. How can i fix it?

eko Over a year ago

@Rohit I've changed the plunker, can you check if it reproduces your issue?

Rohit Over a year ago

I got the issue. Mock service was not returning date for the map(date=> isSameDay(date, new Date())). It was returning string which was creating issue. Thanks for your time.

eko Over a year ago

@Rohit ah, glad you figured it out

DrNio · Accepted Answer · 2017-11-17 00:38:33Z

0

If I were you, I would use a stub service like providers: [ {provide: UserService, useValue: userServiceStub } ]

and you can get it like this userService = fixture.debugElement.injector.get(UserService); or userService = TestBed.get(UserService);

For example:

TestBed.configureTestingModule({
     declarations: [ WelcomeComponent ],
     providers:    [ {provide: UserService, useValue: userServiceStub } ]
  });

  fixture = TestBed.createComponent(WelcomeComponent);
  comp    = fixture.componentInstance;

  // UserService from the root injector
  userService = TestBed.get(UserService);
  ...

answered Nov 17, 2017 at 0:38

DrNio

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Comments

Saurabh Lath · Accepted Answer · 2017-11-17 05:59:23Z

0

If you need to test isSameDay function, you could convert it into a service and treat it the same as any other service. Just like LoggerService in your case.

The benefit with this approach is that you can test your function/service in isolation.

When writing component tests, you can always mock this new service call. Again,this helps you test your component in isolation.

answered Nov 17, 2017 at 5:59

Saurabh Lath

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