text: /* global describe, it */
  
  var assert = require('assert')
  var bigi = require('bigi')
  var DinPay = require('../../')
  var crypto = require('crypto')
  
  var ecurve = require('ecurve')
  var secp256k1 = ecurve.getCurveByName('secp256k1')
  
  describe('DinPayJS (BIP32)', function () {
    it('can create a BIP32 wallet external address', function () {
      var path = "m/0'/0/0"
      var root = DinPay.HDNode.fromSeedHex('dddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddd')
  
      var child1 = root.derivePath(path)
  
      // option 2, manually
      var child2 = root.deriveHardened(0)
        .derive(0)
        .derive(0)
  
      assert.equal(child1.getAddress(), 'AZXdSTRFGHPokX6yfXTfHcTzzHKncioj31')
      assert.equal(child2.getAddress(), 'AZXdSTRFGHPokX6yfXTfHcTzzHKncioj31')
    })
  
    it('can create a BIP44, DinPay, account 0, external address', function () {
      var path = "m/44'/0'/0'/0/0"
      var root = DinPay.HDNode.fromSeedHex('dddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddd')
  
      var child1 = root.derivePath(path)
  
      // option 2, manually
      var child2 = root.deriveHardened(44)
        .deriveHardened(0)
        .deriveHardened(0)
        .derive(0)
        .derive(0)
  
      assert.equal(child1.getAddress(), 'AVbXc2KyxtXeAP9zQpp7ixsnaxEEQ6wZbq')
      assert.equal(child2.getAddress(), 'AVbXc2KyxtXeAP9zQpp7ixsnaxEEQ6wZbq')
    })
  
    it('can recover a BIP32 parent private key from the parent public key, and a derived, non-hardened child private key', function () {
      function recoverParent (master, child) {
        assert(!master.keyPair.d, 'You already have the parent private key')
        assert(child.keyPair.d, 'Missing child private key')
  
        var curve = secp256k1
        var QP = master.keyPair.Q
        var serQP = master.keyPair.getPublicKeyBuffer()
  
        var d1 = child.keyPair.d
        var d2
        var data = new Buffer(37)
        serQP.copy(data, 0)
  
        // search index space until we find it
        for (var i = 0; i < DinPay.HDNode.HIGHEST_BIT; ++i) {
          data.writeUInt32BE(i, 33)
  
          // calculate I
          var I = crypto.createHmac('sha512', master.chainCode).update(data).digest()
          var IL = I.slice(0, 32)
          var pIL = bigi.fromBuffer(IL)
  
          // See hdnode.js:273 to understand
          d2 = d1.subtract(pIL).mod(curve.n)
  
          var Qp = new DinPay.ECPair(d2).Q
          if (Qp.equals(QP)) break
        }
  
        var node = new DinPay.HDNode(new DinPay.ECPair(d2), master.chainCode, master.network)
        node.depth = master.depth
        node.index = master.index
        node.masterFingerprint = master.masterFingerprint
        return node
      }
  
      var seed = crypto.randomBytes(32)
      var master = DinPay.HDNode.fromSeedBuffer(seed)
      var child = master.derive(6) // m/6
  
      // now for the recovery
      var neuteredMaster = master.neutered()
      var recovered = recoverParent(neuteredMaster, child)
      assert.strictEqual(recovered.toBase58(), master.toBase58())
    })
  })
  