angular - ngrx 4 testing effects jasmine-marbels -

i working on testing effects in ngrx store. , after updating ngrx version i've found way, how test it, has been changed.

import { hot, cold } 'jasmine-marbles';  it('should work', () => {    actions = hot('--a-', { a: someaction });     const expected = cold('--b', { b: anotheraction });     expect(effects.somesource$).tobeobservable(expected); });   

unfortunately didn't find documentations jasmine-marbels. explain mean first parameter hot cold functions? , possible find documentation it?

finally found documentation https://github.com/reactivex/rxjs/blob/master/doc/writing-marble-tests.md

probably helpful 1 else.