text: #!/usr/bin/env python3
  # Copyright (c) 2015-2020 The MicroBitcoin Core developers
  # Distributed under the MIT software license, see the accompanying
  # file COPYING or http://www.opensource.org/licenses/mit-license.php.
  """Test BIP65 (CHECKLOCKTIMEVERIFY).
  
  Test that the CHECKLOCKTIMEVERIFY soft-fork activates at (regtest) block height
  1351.
  """
  
  from test_framework.blocktools import (
      create_block,
      create_coinbase,
  )
  from test_framework.messages import (
      CTransaction,
      msg_block,
  )
  from test_framework.p2p import P2PInterface
  from test_framework.script import (
      CScript,
      CScriptNum,
      OP_1NEGATE,
      OP_CHECKLOCKTIMEVERIFY,
      OP_DROP,
  )
  from test_framework.test_framework import MicroBitcoinTestFramework
  from test_framework.util import assert_equal
  from test_framework.wallet import (
      MiniWallet,
      MiniWalletMode,
  )
  
  CLTV_HEIGHT = 1351
  
  
  # Helper function to modify a transaction by
  # 1) prepending a given script to the scriptSig of vin 0 and
  # 2) (optionally) modify the nSequence of vin 0 and the tx's nLockTime
  def cltv_modify_tx(tx, prepend_scriptsig, nsequence=None, nlocktime=None):
      assert_equal(len(tx.vin), 1)
      if nsequence is not None:
          tx.vin[0].nSequence = nsequence
          tx.nLockTime = nlocktime
  
      tx.vin[0].scriptSig = CScript(prepend_scriptsig + list(CScript(tx.vin[0].scriptSig)))
      tx.rehash()
  
  
  def cltv_invalidate(tx, failure_reason):
      # Modify the signature in vin 0 and nSequence/nLockTime of the tx to fail CLTV
      #
      # According to BIP65, OP_CHECKLOCKTIMEVERIFY can fail due the following reasons:
      # 1) the stack is empty
      # 2) the top item on the stack is less than 0
      # 3) the lock-time type (height vs. timestamp) of the top stack item and the
      #    nLockTime field are not the same
      # 4) the top stack item is greater than the transaction's nLockTime field
      # 5) the nSequence field of the txin is 0xffffffff
      assert failure_reason in range(5)
      scheme = [
          # | Script to prepend to scriptSig                  | nSequence  | nLockTime    |
          # +-------------------------------------------------+------------+--------------+
          [[OP_CHECKLOCKTIMEVERIFY],                            None,       None],
          [[OP_1NEGATE, OP_CHECKLOCKTIMEVERIFY, OP_DROP],       None,       None],
          [[CScriptNum(1000), OP_CHECKLOCKTIMEVERIFY, OP_DROP], 0,          1296688602],  # timestamp of genesis block
          [[CScriptNum(1000), OP_CHECKLOCKTIMEVERIFY, OP_DROP], 0,          500],
          [[CScriptNum(500),  OP_CHECKLOCKTIMEVERIFY, OP_DROP], 0xffffffff, 500],
      ][failure_reason]
  
      cltv_modify_tx(tx, prepend_scriptsig=scheme[0], nsequence=scheme[1], nlocktime=scheme[2])
  
  
  def cltv_validate(tx, height):
      # Modify the signature in vin 0 and nSequence/nLockTime of the tx to pass CLTV
      scheme = [[CScriptNum(height), OP_CHECKLOCKTIMEVERIFY, OP_DROP], 0, height]
  
      cltv_modify_tx(tx, prepend_scriptsig=scheme[0], nsequence=scheme[1], nlocktime=scheme[2])
  
  
  class BIP65Test(MicroBitcoinTestFramework):
      def set_test_params(self):
          self.num_nodes = 1
          self.extra_args = [[
              '-whitelist=noban@127.0.0.1',
              '-par=1',  # Use only one script thread to get the exact reject reason for testing
              '-acceptnonstdtxn=1',  # cltv_invalidate is nonstandard
          ]]
          self.setup_clean_chain = True
          self.rpc_timeout = 480
  
      def test_cltv_info(self, *, is_active):
          assert_equal(self.nodes[0].getblockchaininfo()['softforks']['bip65'], {
                  "active": is_active,
                  "height": CLTV_HEIGHT,
                  "type": "buried",
              },
          )
  
      def run_test(self):
          peer = self.nodes[0].add_p2p_connection(P2PInterface())
          wallet = MiniWallet(self.nodes[0], mode=MiniWalletMode.RAW_OP_TRUE)
  
          self.test_cltv_info(is_active=False)
  
          self.log.info("Mining %d blocks", CLTV_HEIGHT - 2)
          wallet.generate(10)
          self.nodes[0].generate(CLTV_HEIGHT - 2 - 10)
  
          self.log.info("Test that invalid-according-to-CLTV transactions can still appear in a block")
  
          # create one invalid tx per CLTV failure reason (5 in total) and collect them
          invalid_cltv_txs = []
          for i in range(5):
              spendtx = wallet.create_self_transfer(from_node=self.nodes[0])['tx']
              cltv_invalidate(spendtx, i)
              invalid_cltv_txs.append(spendtx)
  
          tip = self.nodes[0].getbestblockhash()
          block_time = self.nodes[0].getblockheader(tip)['mediantime'] + 1
          block = create_block(int(tip, 16), create_coinbase(CLTV_HEIGHT - 1), block_time)
          block.nVersion = 3
          block.vtx.extend(invalid_cltv_txs)
          block.hashMerkleRoot = block.calc_merkle_root()
          block.solve()
  
          self.test_cltv_info(is_active=False)  # Not active as of current tip and next block does not need to obey rules
          peer.send_and_ping(msg_block(block))
          self.test_cltv_info(is_active=True)  # Not active as of current tip, but next block must obey rules
          assert_equal(self.nodes[0].getbestblockhash(), block.hash)
  
          self.log.info("Test that blocks must now be at least version 4")
          tip = block.sha256
          block_time += 1
          block = create_block(tip, create_coinbase(CLTV_HEIGHT), block_time)
          block.nVersion = 3
          block.solve()
  
          with self.nodes[0].assert_debug_log(expected_msgs=['{}, bad-version(0x00000003)'.format(block.hash)]):
              peer.send_and_ping(msg_block(block))
              assert_equal(int(self.nodes[0].getbestblockhash(), 16), tip)
              peer.sync_with_ping()
  
          self.log.info("Test that invalid-according-to-CLTV transactions cannot appear in a block")
          block.nVersion = 4
          block.vtx.append(CTransaction()) # dummy tx after coinbase that will be replaced later
  
          # create and test one invalid tx per CLTV failure reason (5 in total)
          for i in range(5):
              spendtx = wallet.create_self_transfer(from_node=self.nodes[0])['tx']
              cltv_invalidate(spendtx, i)
  
              expected_cltv_reject_reason = [
                  "non-mandatory-script-verify-flag (Operation not valid with the current stack size)",
                  "non-mandatory-script-verify-flag (Negative locktime)",
                  "non-mandatory-script-verify-flag (Locktime requirement not satisfied)",
                  "non-mandatory-script-verify-flag (Locktime requirement not satisfied)",
                  "non-mandatory-script-verify-flag (Locktime requirement not satisfied)",
              ][i]
              # First we show that this tx is valid except for CLTV by getting it
              # rejected from the mempool for exactly that reason.
              assert_equal(
                  [{
                      'txid': spendtx.hash,
                      'wtxid': spendtx.getwtxid(),
                      'allowed': False,
                      'reject-reason': expected_cltv_reject_reason,
                  }],
                  self.nodes[0].testmempoolaccept(rawtxs=[spendtx.serialize().hex()], maxfeerate=0),
              )
  
              # Now we verify that a block with this transaction is also invalid.
              block.vtx[1] = spendtx
              block.hashMerkleRoot = block.calc_merkle_root()
              block.solve()
  
              with self.nodes[0].assert_debug_log(expected_msgs=['CheckInputScripts on {} failed with {}'.format(
                                                  block.vtx[-1].hash, expected_cltv_reject_reason)]):
                  peer.send_and_ping(msg_block(block))
                  assert_equal(int(self.nodes[0].getbestblockhash(), 16), tip)
                  peer.sync_with_ping()
  
          self.log.info("Test that a version 4 block with a valid-according-to-CLTV transaction is accepted")
          cltv_validate(spendtx, CLTV_HEIGHT - 1)
  
          block.vtx.pop(1)
          block.vtx.append(spendtx)
          block.hashMerkleRoot = block.calc_merkle_root()
          block.solve()
  
          self.test_cltv_info(is_active=True)  # Not active as of current tip, but next block must obey rules
          peer.send_and_ping(msg_block(block))
          self.test_cltv_info(is_active=True)  # Active as of current tip
          assert_equal(int(self.nodes[0].getbestblockhash(), 16), block.sha256)
  
  
  if __name__ == '__main__':
      BIP65Test().main()
  