node-tap

'use strict'

const tap = require('tap')

function fizz(number) {
  return number%3 === 0 ? 'fizz' : ''
}

function buzz(number) {
  return number%5 === 0 ? 'buzz' : ''
}

function fizzBuzz (ret) {
  let res = ''
  res += fizz(ret)
  res += buzz(ret)
  return res === '' ? ret : res
}

tap.equal(fizzBuzz(2), 2, 'Write a program that prints the numbers from 1 to 100.')
tap.equal(fizzBuzz(3), 'fizz', 'But for multiples of three print “Fizz.')
tap.equal(fizzBuzz(5), 'buzz', 'Instead of the number and for the multiples of five print “Buzz”.')
tap.equal(fizzBuzz(15), 'fizzbuzz', 'For numbers which are multiples of both three and five print “FizzBuzz”.')