const expect = require('expect'); const mapKeys = require('./mapKeys.js'); test('Testing mapKeys', () => { //For more information on all the methods supported by tape //Please go to https://github.com/substack/tape expect(typeof mapKeys === 'function').toBeTruthy(); expect(mapKeys({ a: 1, b: 2 }, (val, key) => key + val)).toEqual({ a1: 1, b2: 2 }); });