text: #!/usr/bin/env python2
  # Copyright (c) 2014 The Bitcoin Core developers
  # Distributed under the MIT software license, see the accompanying
  # file COPYING or http://www.opensource.org/licenses/mit-license.php.
  
  from test_framework.test_framework import HodlCashTestFramework
  from test_framework.util import *
  
  from binascii import a2b_hex, b2a_hex
  from hashlib import sha256
  from struct import pack
  
  
  def check_array_result(object_array, to_match, expected):
      """
      Pass in array of JSON objects, a dictionary with key/value pairs
      to match against, and another dictionary with expected key/value
      pairs.
      """
      num_matched = 0
      for item in object_array:
          all_match = True
          for key,value in to_match.items():
              if item[key] != value:
                  all_match = False
          if not all_match:
              continue
          for key,value in expected.items():
              if item[key] != value:
                  raise AssertionError("%s : expected %s=%s"%(str(item), str(key), str(value)))
              num_matched = num_matched+1
      if num_matched == 0:
          raise AssertionError("No objects matched %s"%(str(to_match)))
  
  def b2x(b):
      return b2a_hex(b).decode('ascii')
  
  # NOTE: This does not work for signed numbers (set the high bit) or zero (use b'\0')
  def encodeUNum(n):
      s = bytearray(b'\1')
      while n > 127:
          s[0] += 1
          s.append(n % 256)
          n //= 256
      s.append(n)
      return bytes(s)
  
  def varlenEncode(n):
      if n < 0xfd:
          return pack('<B', n)
      if n <= 0xffff:
          return b'\xfd' + pack('<H', n)
      if n <= 0xffffffff:
          return b'\xfe' + pack('<L', n)
      return b'\xff' + pack('<Q', n)
  
  def dblsha(b):
      return sha256(sha256(b).digest()).digest()
  
  def genmrklroot(leaflist):
      cur = leaflist
      while len(cur) > 1:
          n = []
          if len(cur) & 1:
              cur.append(cur[-1])
          for i in range(0, len(cur), 2):
              n.append(dblsha(cur[i] + cur[i+1]))
          cur = n
      return cur[0]
  
  def template_to_bytes(tmpl, txlist):
      blkver = pack('<L', tmpl['version'])
      mrklroot = genmrklroot(list(dblsha(a) for a in txlist))
      timestamp = pack('<L', tmpl['curtime'])
      nonce = b'\0\0\0\0'
      blk = blkver + a2b_hex(tmpl['previousblockhash'])[::-1] + mrklroot + timestamp + a2b_hex(tmpl['bits'])[::-1] + nonce
      blk += varlenEncode(len(txlist))
      for tx in txlist:
          blk += tx
      return blk
  
  def template_to_hex(tmpl, txlist):
      return b2x(template_to_bytes(tmpl, txlist))
  
  def assert_template(node, tmpl, txlist, expect):
      rsp = node.getblocktemplate({'data':template_to_hex(tmpl, txlist),'mode':'proposal'})
      if rsp != expect:
          raise AssertionError('unexpected: %s' % (rsp,))
  
  class GetBlockTemplateProposalTest(HodlCashTestFramework):
      '''
      Test block proposals with getblocktemplate.
      '''
  
      def run_test(self):
          node = self.nodes[0]
          node.generate(1) # Mine a block to leave initial block download
          tmpl = node.getblocktemplate()
          if 'coinbasetxn' not in tmpl:
              rawcoinbase = encodeUNum(tmpl['height'])
              rawcoinbase += b'\x01-'
              hexcoinbase = b2x(rawcoinbase)
              hexoutval = b2x(pack('<Q', tmpl['coinbasevalue']))
              tmpl['coinbasetxn'] = {'data': '01000000' + '01' + '0000000000000000000000000000000000000000000000000000000000000000ffffffff' + ('%02x' % (len(rawcoinbase),)) + hexcoinbase + 'fffffffe' + '01' + hexoutval + '00' + '00000000'}
          txlist = list(bytearray(a2b_hex(a['data'])) for a in (tmpl['coinbasetxn'],) + tuple(tmpl['transactions']))
  
          # Test 0: Capability advertised
          assert('proposal' in tmpl['capabilities'])
  
          # NOTE: This test currently FAILS (regtest mode doesn't enforce block height in coinbase)
          ## Test 1: Bad height in coinbase
          #txlist[0][4+1+36+1+1] += 1
          #assert_template(node, tmpl, txlist, 'FIXME')
          #txlist[0][4+1+36+1+1] -= 1
  
          # Test 2: Bad input hash for gen tx
          txlist[0][4+1] += 1
          assert_template(node, tmpl, txlist, 'bad-cb-missing')
          txlist[0][4+1] -= 1
  
          # Test 3: Truncated final tx
          lastbyte = txlist[-1].pop()
          try:
              assert_template(node, tmpl, txlist, 'n/a')
          except JSONRPCException:
              pass  # Expected
          txlist[-1].append(lastbyte)
  
          # Test 4: Add an invalid tx to the end (duplicate of gen tx)
          txlist.append(txlist[0])
          assert_template(node, tmpl, txlist, 'bad-txns-duplicate')
          txlist.pop()
  
          # Test 5: Add an invalid tx to the end (non-duplicate)
          txlist.append(bytearray(txlist[0]))
          txlist[-1][4+1] = b'\xff'
          assert_template(node, tmpl, txlist, 'bad-txns-inputs-missingorspent')
          txlist.pop()
  
          # Test 6: Future tx lock time
          txlist[0][-4:] = b'\xff\xff\xff\xff'
          assert_template(node, tmpl, txlist, 'bad-txns-nonfinal')
          txlist[0][-4:] = b'\0\0\0\0'
  
          # Test 7: Bad tx count
          txlist.append(b'')
          try:
              assert_template(node, tmpl, txlist, 'n/a')
          except JSONRPCException:
              pass  # Expected
          txlist.pop()
  
          # Test 8: Bad bits
          realbits = tmpl['bits']
          tmpl['bits'] = '1c0000ff'  # impossible in the real world
          assert_template(node, tmpl, txlist, 'bad-diffbits')
          tmpl['bits'] = realbits
  
          # Test 9: Bad merkle root
          rawtmpl = template_to_bytes(tmpl, txlist)
          rawtmpl[4+32] = (rawtmpl[4+32] + 1) % 0x100
          rsp = node.getblocktemplate({'data':b2x(rawtmpl),'mode':'proposal'})
          if rsp != 'bad-txnmrklroot':
              raise AssertionError('unexpected: %s' % (rsp,))
  
          # Test 10: Bad timestamps
          realtime = tmpl['curtime']
          tmpl['curtime'] = 0x7fffffff
          assert_template(node, tmpl, txlist, 'time-too-new')
          tmpl['curtime'] = 0
          assert_template(node, tmpl, txlist, 'time-too-old')
          tmpl['curtime'] = realtime
  
          # Test 11: Valid block
          assert_template(node, tmpl, txlist, None)
  
          # Test 12: Orphan block
          tmpl['previousblockhash'] = 'ff00' * 16
          assert_template(node, tmpl, txlist, 'inconclusive-not-best-prevblk')
  
  if __name__ == '__main__':
      GetBlockTemplateProposalTest().main()
  