const transform = require('..')
const assert = require('assert')

transform([
  ['1','2','3','4'],
  ['a','b','c','d']
], function(data){
  data.push(data.shift())
  return data
}, function(err, output){
  assert.deepEqual(output, [
    [ '2', '3', '4', '1' ],
    [ 'b', 'c', 'd', 'a' ]
  ])
})