NGXS: How to test if an action was dispatched?

Question

How to unit test whether an action was dispatched?

For example, in a LogoutService, I have this simple method:

  logout(username: string) {
    store.dis         


        

Answer 1

Using Jasmine Spies

I believe that in unit testing the actual implementation of all the related dependencies should be mocked and hence we should not be including any actual stores in here. Here we are providing a jasmine spy for Store and just checking whether certain actions are dispatched with correct parameters. This could also be used to provide stub data too.

describe('LogoutService', () => {
  let storeSpy: jasmine.SpyObj;

  beforeEach(() => {
    storeSpy = jasmine.createSpyObj(['dispatch']);

    TestBed.configureTestingModule({
      providers: [LogoutService, { provide: Store, useValue: storeSpy }]
    });
  })

  it('should dispatch Logout and Reset actions', () => {
    storeSpy.dispatch.withArgs([
      jasmine.any(ResetStateAction), 
      jasmine.any(LogoutAction)])
     .and
     .callFake(([resetAction, logoutAction]) => {
       expect(resetAction.payload).toEqual({...something});
       expect(logoutAction.payload).toEqual({...somethingElse});
    });

    TestBed.inject(LogoutService).logout();
});