import { NEVER } from 'rxjs' ; import { expect } from 'chai' ; import { expectObservable } from '../helpers/marble-testing' ; test describe ( 'NEVER' , ( ) => { it ( 'should create a cold observable that never emits' , ( ) => { const expected = '-' ; const e1 = NEVER ; expectObservable ( e1 ) . toBe ( expected ) ; } ) ; it ( 'should return the same instance every time' , ( ) => { expect ( NEVER ) . to . equal ( NEVER ) ; } ) ; } ) ;