wallet-bip32-fundraiser-vs-wordcodec_tests.js

var test = require('tape')
const randomBytes = require('randombytes')
const bip39 = require('bip39')

test('generate wallet mnemonic', function (t) {

  t.test('some bip39 experiments: can we "revert" "BytesToWords" with "WordsToBytes" like in TestCheckTypoDetection', function (t) {
    // see https://github.com/tendermint/go-crypto/blob/906331a8d1661a504dc0eb2618a8767363fddb7c/keys/words/wordcodec_test.go#L146-L178
    var strength = 128
    for (var i = 0; i < 3400; i++) {
      // new entropy:
      var data = randomBytes(strength / 8).toString('hex')

      // corresponds to:
      // words, err := codec.BytesToWords(data)
      // default word list is english:
      var words = bip39.entropyToMnemonic(data)

      // coresponds to:
      // good, err := codec.WordsToBytes(words)
      // default word list is english:
      var good = bip39.mnemonicToEntropy(words)

      t.equal(data, good)

      // now try some tweaks...
       try {
        var cut = words.split(' ').slice(1).join(' ')
        bip39.mnemonicToEntropy(cut)
        t.fail('should have thrown')
      } catch (err) {
        t.ok(err, 'error was thrown')
        t.equal(err.message, 'Invalid mnemonic', 'correct error message')
      }

      var diffWords = words.split(' ')
      diffWords[3] = getDiffWord(diffWords[3])
      var df = diffWords.join(' ')
      try {
        bip39.mnemonicToEntropy(df)
        t.fail('should have thrown')
      } catch (err) {
        t.ok(err, 'error was thrown')
        t.equal(err.message, 'Invalid mnemonic checksum', 'correct error message')
      }
    }
    t.end()
  })

  t.end()
})

function getDiffWord(not) {
  var banksize = bip39.wordlists.EN.length
  var idx = Math.floor(Math.random() * banksize) % banksize
  var w = bip39.wordlists.EN[idx]
  if (w === not) {
    w = getDiffWord(not)
  }
  return w
}