Roman numbers kata https://cyber-dojo.org/kata/edit/kAGG46

roman.js

'use strict';

module.exports = {
  roman
};

function roman(arabic) {
  let r = "I".repeat(arabic);
  if (arabic === 4) {
    return "IV";
  }
  return r;
}

romanTest.js

'use strict';

const roman = require('./roman.js');

describe('Should convert roman', () => {
  it('from 1', () => roman.roman(1).should.equal("I"));
  it('from 2', () => roman.roman(2).should.equal("II"));
  it('from 3', () => roman.roman(3).should.equal("III")); 
  it('from 4', () => roman.roman(4).should.equal("IV")); 
});