javascript - How do I get TestScheduler to tick in RxJs5? -

i'm trying write sample unit test observable.interval in rxjs version 5. i'm running following code, observable fires once, not 20 times, anticipated.

it('does interval thing synchonously', ()=> {          let x = [];         let scheduler = new rx.testscheduler();         let interval$ = rx.observable.interval(500, scheduler).take(20);          interval$.subscribe(             value => {                 x.push(value);                 console.log(value)             },         );          for(let = 0; < 20; i++) {             scheduler.flush();         }          expect(x.length).tobe(20);      }); 

how make testscheduler move observable forward 10000 milliseconds?

my understanding testscheduler intended used marble testing , works observables composed returned createcoldobservable , createhotobservable methods.

instead, use virtualtimescheduler - upon testscheduler based:

let scheduler = new rx.virtualtimescheduler();  let interval$ = rx.observable.interval(500, scheduler).take(20);    let values = [];  interval$.subscribe(value => values.push(value));    scheduler.flush();  console.log(values);

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<script src="https://unpkg.com/rxjs/bundles/rx.min.js"></script>

note single flush call required.