playing with possible js quickcheck API

generators.js

// generators make random content of a type

// -- utils
var randNth = function(coll) { 
  return coll[Math.floor(Math.random() * coll.length)]
}

var randChar = function(){ 
  return randNth('qwertyuiopasdfghjklzxcvbnm')
}

var repeat = function(n, fn){
  var arr = []
  for ( var i = 0; i < n; i += 1 ) arr.push(fn())
  return arr
}

// -- generators
var str = function(){
  var len = Math.floor(Math.random() * 100)
  return repeat(len, randChar).join('')
}

var int = function(){
  return Math.floor(Math.random() * 10000000)
}


module.exports = { int: int, str: str }

qc-test.js

var types = require('generators')
var qc = require('quickcheck')

// under test function
var reverse = function(a){ return a.slice().reverse() }

// quickcheck generates n elements in arrays, and throws an error of the agregated failures 
// after the tests are run, if there are any
qc([types.str], function(arr){ reverse(reverse(arr)).join('') === arr.join('') })

with-mocha.js

var types = require('generators')
var qc = require('quickcheck')

// under test function
var reverse = function(a){ return a.slice().reverse() }


suite('reverse')

// qc.test is the same as qc, except that it's a shorthand for qc.bind(null, /* etc */)
test('reverse reverse is the same as no reverse', qc.test([types.str], 
  function(arr){ reverse(reverse(arr)).join('') === arr.join('') 
}))