Test to reproduce a transaction with a time based locktime that is replaced

time_based_rbf.py

#!/usr/bin/env python3
# Copyright (c) 2014-present The Bitcoin Core developers
# Distributed under the MIT software license, see the accompanying
# file COPYING or http://www.opensource.org/licenses/mit-license.php.
"""Test to reproduce a transaction with a time based locktime that is replaced.
     It shouldn't do anti fee sniping in this case, as it can be easily identified that
     anti fee sniping is being applied and also the locktime type shoulnd't change
     without the user consent."""
    
# To run it: python3 test/functional/rbf_time_based.py --configfile build/test/config.ini

from test_framework.test_framework import BitcoinTestFramework

def get_change_address(tx, node):
    tx_details = node.getrawtransaction(tx, 1)
    txout_addresses = [txout['scriptPubKey']['address'] for txout in tx_details["vout"]]
    return [address for address in txout_addresses if node.getaddressinfo(address)["ischange"]]


class ReplaceByFeeTimeBasedLocktime(BitcoinTestFramework):
    def set_test_params(self):
        self.num_nodes = 2
        self.uses_wallet = None
        self.extra_args = [["-deprecatedrpc=fullrbf", "-deprecatedrpc=bip125"], []]

    def run_test(self):
        self.nodes[0].createwallet("rbf")
        wallet = self.nodes[0].get_wallet_rpc("rbf")
        self.generatetoaddress(self.nodes[0], 101, wallet.getnewaddress())
        
        tip_height = self.nodes[0].getblockchaininfo()["blocks"]

        self.log.info(f"Creating a transation with time based lockitme: 500000000")
        tx = wallet.send(outputs={wallet.getnewaddress(): 9}, fee_rate=1, locktime=500000000)
        hex_tx = self.nodes[0].getrawtransaction(tx["txid"])
    
        # Replacement with higher fee_rate
        change_addr = get_change_address(tx["txid"], wallet)[0]
        bumped = wallet.bumpfee(txid=tx["txid"], options={"fee_rate":5, "outputs": [{change_addr: 10}]})
        
        locktime = self.nodes[0].getrawtransaction(bumped["txid"],True)["locktime"]
        
        
        self.log.info(f"The replacement should have the same locktime and shouldn't do anti fee sniping")
        self.log.info(f"However the new locktime is: {locktime}")
        
        self.log.info(f"Hexadecimals of the transations")
        self.log.info(f"Original: {hex_tx}")
        self.log.info(f"Replacement: {self.nodes[0].getrawtransaction(bumped["txid"])}")
          
        

        
if __name__ == '__main__':
    ReplaceByFeeTimeBasedLocktime(__file__).main()