prettier import { expect } from 'chai' ; import { empty , EMPTY } from 'rxjs' ; import { TestScheduler } from 'rxjs/testing' ; import { observableMatcher } from '../helpers/observableMatcher' ; test describe ( 'empty' , ( ) => { let rxTestScheduler ; beforeEach ( ( ) => { rxTestScheduler = new TestScheduler ( observableMatcher ) ; } ) ; it ( 'should return EMPTY' , ( ) => { expect ( empty ( ) ) . to . equal ( EMPTY ) ; } ) ; it ( 'should create a cold observable with only complete' , ( ) => { rxTestScheduler . run ( ( { expectObservable } ) => { const expected = '|' ; const e1 = empty ( ) ; expectObservable ( e1 ) . toBe ( expected ) ; } ) ; } ) ; it ( 'should return the same instance EMPTY' , ( ) => { const s1 = empty ( ) ; const s2 = empty ( ) ; expect ( s1 ) . to . equal ( s2 ) ; } ) ; it ( 'should be synchronous by default' , ( ) => { const source = empty ( ) ; let hit = false ; source . subscribe ( { complete ( ) { hit = true ; } , } ) ; expect ( hit ) . to . be . true ; } ) ; it ( 'should equal EMPTY' , ( ) => { expect ( empty ( ) ) . to . equal ( EMPTY ) ; } ) ; it ( 'should take a scheduler' , ( ) => { const source = empty ( rxTestScheduler ) ; let hit = false ; source . subscribe ( { complete ( ) { hit = true ; } , } ) ; expect ( hit ) . to . be . false ; rxTestScheduler . flush ( ) ; expect ( hit ) . to . be . true ; } ) ; } ) ;