patience-diff/test.js

Linear Diff algorithm for Arrays.

var tape = require('tape')
var MyersDiff = require('./')

tape('INSERT at start', function (test) {
  var differ = new MyersDiff()
  compare(test, differ, {
    current: [ 'a' ],
    desired: [ 'b', 'a' ],
    instructions: [ 2, 0, 0, 0 ]
  })

  test.end()
})

tape('INSERT at end', function (test) {
  var differ = new MyersDiff()
  compare(test, differ, {
    current: [ 'a' ],
    desired: [ 'a', 'b' ],
    instructions: [ 2, 1, 1, 0 ]
  })

  test.end()
})

// Helper function to run a comparison.
function compare (t, differ, args) {
  differ.diff(args.current, args.desired)
  var instructions = args.instructions

  var output = new Array(instructions.length)
  output.fill('0x0000')
  var i = 0
  var el
  while (true) {
    el = differ.instructions[i]
    output[i] = hex(el)
    if (el === 0) break
    i++
  }

  instructions.forEach(function (instruction, i) {
    instructions[i] = hex(instruction || 0)
  })

  t.equal(output.toString(), instructions.toString(), 'result was same')
}
function hex (number) {
  var str = (number).toString(16)
  while (str.length < 4) str = '0' + str
  return '0x' + str
}