jasmine angular2 check array length toEqual return true

Question

Hi I am new to angular2 and just finished the heroes example. I thought it would be good to add unit test and I started with hero.service.

this is hero service

getHeroes():Promise{

return this.http.get(this.heroesUrl ).toPromise().then(response=>response.json().data as Hero[]).catch(this.handleError);

}

this is my unit test

const fakedHeroes:Hero[]=[
  { id: 1, name: 'Windstorm' },
  { id: 2, name: 'Bombasto' },
  { id: 3, name: 'Magneta' },
  { id: 4, name: 'Tornado' }
]
 describe('get Heroes test',()=>{
    let service:HeroService=null;
    let backend:MockBackend=null;
    beforeEach(inject([HeroService,MockBackend],(heroSerivce:HeroService,mockBackend:MockBackend)=>{
        service=heroSerivce;
        backend=mockBackend;
    }));
    it('get heroes',(done)=>{

        backend.connections.subscribe((connection:MockConnection)=>{
            let options=new ResponseOptions({status: 200, body: {data: fakedHeroes}})
            connection.mockRespond(new Response(options));
        })
        service.getHeroes().then(response=>{
            // console.log(response)
            console.log(response.length)
            expect(response.length).toEqual(2,'should be 4')

        });

        done();
    })
  })

from the console, I can see the length of the response is 4..but the test passes successfully..

Did I miss out anything here?

update1:

I have tried both

expect(response.length).toEqual(2,'should be 4')
expect(response.length).toBe(2,'should be 4')

all pass successfully

Answer 1

The point of done is that is allows you to wait for async tasks to resolve. But you are not waiting for anything. You are calling it synchronously. You should be calling it after the async task resolves (in this case the promise), after you are "done" testing, i.e

service.getHeroes().then(res => {
  expect(...)

  done()
})