https://coderpad.io/sandbox in javascript with mocha tests

even.js

const Mocha = require ('mocha')
const assert = require('chai').assert
const mocha = new Mocha ({ui: 'bdd'})

mocha.suite.emit('pre-require', this, 'solution', mocha)

const even = (n) => n % 2 === 0;  

describe('Test suite', () => {
  it('should work', () => {
    assert(even(2) === true, "two is even")
  })
  it('should work', () => {
    assert(even(3) === false, "three is not even")
  })
})

mocha.run(() => {})