const deferUntilFrame = require( '../../resources/skins.vector.es6/deferUntilFrame.js' ); describe( 'deferUntilFrame.js', () => { let /** @type {jest.SpyInstance} */ spy; beforeEach( () => { spy = jest.spyOn( window, 'requestAnimationFrame' ).mockImplementation( ( cb ) => { setTimeout( () => { cb( 1 ); } ); return 1; } ); } ); afterEach( () => { spy.mockRestore(); } ); it( 'does not fire rAF if `0` is passed', done => { deferUntilFrame( () => { expect( spy ).toHaveBeenCalledTimes( 0 ); done(); }, 0 ); } ); it( 'fires rAF the specified number of times', done => { deferUntilFrame( () => { expect( spy ).toHaveBeenCalledTimes( 3 ); done(); }, 3 ); } ); } );