import { Observable , isObservable } from 'rxjs' ; import { expect } from 'chai' ; describe ( 'isObservable' , ( ) => { it ( 'should return true for RxJS Observable' , ( ) => { const o = new Observable < any > ( ) ; expect ( isObservable ( o ) ) . to . be . true ; } ) ; it ( 'should return true for an observable that comes from another RxJS 5+ library' , ( ) => { const o = { lift ( ) { } , subscribe ( ) { } , } ; expect ( isObservable ( o ) ) . to . be . true ; } ) ; it ( 'should NOT return true for any old subscribable' , ( ) => { const o = { subscribe ( ) { } , } ; expect ( isObservable ( o ) ) . to . be . false ; } ) ; it ( 'should return false for null' , ( ) => { expect ( isObservable ( null ) ) . to . be . false ; } ) ; it ( 'should return false for a number' , ( ) => { expect ( isObservable ( 1 ) ) . to . be . false ; } ) ; } ) ;