const expect = require('expect'); const runPromisesInSeries = require('./runPromisesInSeries.js'); test('runPromisesInSeries is a Function', () => { expect(runPromisesInSeries).toBeInstanceOf(Function); }); const delay = d => new Promise(r => setTimeout(r, d)); test('Runs promises in series', () => { runPromisesInSeries([() => delay(100), () => delay(200).then(() => expect(true).toBeTruthy())]); });