text: #!/usr/bin/env python3
  # -*- coding: utf-8 -*-
  
  import subprocess
  
  from test_framework.messages import CTransaction, CTxIn, CTxOut, COutPoint, COIN
  from test_framework.messages import msg_getheaders, msg_headers, CBlockHeader
  from test_framework.mininode import P2PInterface, mininode_lock
  from test_framework.script import CScript
  from test_framework.util import wait_until
  
  ''' -------------------------------------------------------------------------
  TestNode CLASS --------------------------------------------------------------
  
  A peer we use to send messsages to nxboostd and store responses
  Extends P2PInterface.
  '''
  
  # TestNode: A peer we use to send messages to bitcoind, and store responses.
  class TestNode(P2PInterface):
      def __init__(self):
          super().__init__()
          self.last_sendcmpct = []
          self.block_announced = False
          # Store the hashes of blocks we've seen announced.
          # This is for synchronizing the p2p message traffic,
          # so we can eg wait until a particular block is announced.
          self.announced_blockhashes = set()
  
      def on_sendcmpct(self, message):
          self.last_sendcmpct.append(message)
  
      def on_cmpctblock(self, message):
          self.block_announced = True
          self.last_message["cmpctblock"].header_and_shortids.header.calc_sha256()
          self.announced_blockhashes.add(self.last_message["cmpctblock"].header_and_shortids.header.sha256)
  
      def on_headers(self, message):
          self.block_announced = True
          for x in self.last_message["headers"].headers:
              x.calc_sha256()
              self.announced_blockhashes.add(x.sha256)
  
      def on_inv(self, message):
          for x in self.last_message["inv"].inv:
              if x.type == 2:
                  self.block_announced = True
                  self.announced_blockhashes.add(x.hash)
  
      # Requires caller to hold mininode_lock
      def received_block_announcement(self):
          return self.block_announced
  
      def clear_block_announcement(self):
          with mininode_lock:
              self.block_announced = False
              self.last_message.pop("inv", None)
              self.last_message.pop("headers", None)
              self.last_message.pop("cmpctblock", None)
  
      def get_headers(self, locator, hashstop):
          msg = msg_getheaders()
          msg.locator.vHave = locator
          msg.hashstop = hashstop
          self.connection.send_message(msg)
  
      def send_header_for_blocks(self, new_blocks):
          headers_message = msg_headers()
          headers_message.headers = [CBlockHeader(b) for b in new_blocks]
          self.send_message(headers_message)
  
      def request_headers_and_sync(self, locator, hashstop=0):
          self.clear_block_announcement()
          self.get_headers(locator, hashstop)
          wait_until(self.received_block_announcement, timeout=30, lock=mininode_lock)
          self.clear_block_announcement()
  
      # Block until a block announcement for a particular block hash is received.
      def wait_for_block_announcement(self, block_hash, timeout=30):
          def received_hash():
              return (block_hash in self.announced_blockhashes)
          wait_until(received_hash, timeout=timeout, lock=mininode_lock)
  
      def send_await_disconnect(self, message, timeout=30):
          """Sends a message to the node and wait for disconnect.
  
          This is used when we want to send a message into the node that we expect
          will get us disconnected, eg an invalid block."""
          self.send_message(message)
          wait_until(lambda: not self.connected, timeout=timeout, lock=mininode_lock)
  
  
  
  ''' -------------------------------------------------------------------------
  MISC METHODS ----------------------------------------------------------------
  '''
  
  def dir_size(path):
      ''' returns the size in bytes of the directory at given path
      '''
      size = subprocess.check_output(['du','-shk', path]).split()[0].decode('utf-8')
      return int(size)
  
  
  def create_transaction(outPoint, sig, value, nTime, scriptPubKey=CScript()):
      ''' creates a CTransaction object provided input-output data
      '''
      tx = CTransaction()
      tx.vin.append(CTxIn(outPoint, sig, 0xffffffff))
      tx.vout.append(CTxOut(value, scriptPubKey))
      tx.nTime = nTime
      tx.calc_sha256()
      return tx
  
  
  def utxo_to_stakingPrevOuts(utxo, stakingPrevOuts, txBlocktime, stakeModifier, zpos=False):
      '''
      Updates a map of unspent outputs to (amount, blocktime) to be used as stake inputs
      :param   utxo:     <if zpos=False>  (map) utxo JSON object returned from listunspent
                         <if zpos=True>   (map) mint JSON object returned from listmintedzerocoins
               stakingPrevOuts:   ({COutPoint --> (int, int, int, str)} dictionary)
                                  map outpoints to amount, block_time, nStakeModifier, hashStake hex
               txBlocktime:       (int) block time of the stake Modifier
               stakeModifier:     (int) stake modifier for the current utxo
               zpos:              (bool) if true, utxo holds a zerocoin serial hash
      :return
      '''
  
      COINBASE_MATURITY = 200 if zpos else 100
      if utxo['confirmations'] > COINBASE_MATURITY:
          if zpos:
              outPoint = utxo["serial hash"]
              stakingPrevOuts[outPoint] = (int(utxo["denomination"]) * COIN, txBlocktime, stakeModifier, utxo['hash stake'])
          else:
              outPoint = COutPoint(int(utxo['txid'], 16), utxo['vout'])
              stakingPrevOuts[outPoint] = (int(utxo['amount'])*COIN, txBlocktime, stakeModifier, "")
  
      return
  