const getCreationDate = require('../util/getCreationDate'); const users = [ { user: { createdAt: new Date("2016-01-29T14:47:58.915Z") } }, { user: { createdAt: new Date("2018-08-20T15:51:47.090Z") } }, { user: { createdAt: new Date("2019-04-08T21:08:11.212Z") } } ] const humanReadableTime = [ "2016-01-29 14:47:58", "2018-08-20 15:51:47", "2019-04-08 21:08:11" ] test('Testing getCreationDate', () => { for(let i = 0; i < users.length; i++){ expect(getCreationDate(users[i])).toBe(humanReadableTime[i]) } });