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Add tests for transaction replacement
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‎qa/replace-by-fee/.gitignore

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python-bitcoinlib

‎qa/replace-by-fee/README.md

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Replace-by-fee regression tests
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===============================
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First get version v0.5.0 of the python-bitcoinlib library. In this directory
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run:
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git clone -n https://github.com/petertodd/python-bitcoinlib
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(cd python-bitcoinlib && git checkout 8270bfd9c6ac37907d75db3d8b9152d61c7255cd)
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Then run the tests themselves with a bitcoind available running in regtest
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mode:
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./rbf-tests.py

‎qa/replace-by-fee/rbf-tests.py

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#!/usr/bin/env python3
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# Copyright (c) 2015 The Bitcoin Core developers
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# Distributed under the MIT software license, see the accompanying
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# file COPYING or http://www.opensource.org/licenses/mit-license.php.
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#
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# Test replace-by-fee
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#
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import os
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import sys
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# Add python-bitcoinlib to module search path:
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sys.path.append(os.path.join(os.path.dirname(os.path.abspath(__file__)), "python-bitcoinlib"))
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import unittest
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import bitcoin
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bitcoin.SelectParams('regtest')
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import bitcoin.rpc
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from bitcoin.core import *
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from bitcoin.core.script import *
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from bitcoin.wallet import *
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MAX_REPLACEMENT_LIMIT = 100
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class Test_ReplaceByFee(unittest.TestCase):
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proxy = None
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@classmethod
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def setUpClass(cls):
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if cls.proxy is None:
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cls.proxy = bitcoin.rpc.Proxy()
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@classmethod
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def tearDownClass(cls):
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# Make sure mining works
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mempool_size = 1
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while mempool_size:
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cls.proxy.call('generate',1)
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new_mempool_size = len(cls.proxy.getrawmempool())
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# It's possible to get stuck in a loop here if the mempool has
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# transactions that can't be mined.
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assert(new_mempool_size != mempool_size)
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mempool_size = new_mempool_size
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def make_txout(self, amount, scriptPubKey=CScript([1])):
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"""Create a txout with a given amount and scriptPubKey
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Mines coins as needed.
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"""
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fee = 1*COIN
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while self.proxy.getbalance() < amount + fee:
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self.proxy.call('generate', 100)
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addr = P2SHBitcoinAddress.from_redeemScript(CScript([]))
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txid = self.proxy.sendtoaddress(addr, amount + fee)
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tx1 = self.proxy.getrawtransaction(txid)
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i = None
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for i, txout in enumerate(tx1.vout):
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if txout.scriptPubKey == addr.to_scriptPubKey():
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break
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assert i is not None
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tx2 = CTransaction([CTxIn(COutPoint(txid, i), CScript([1, CScript([])]), nSequence=0)],
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[CTxOut(amount, scriptPubKey)])
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tx2_txid = self.proxy.sendrawtransaction(tx2, True)
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return COutPoint(tx2_txid, 0)
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def test_simple_doublespend(self):
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"""Simple doublespend"""
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tx0_outpoint = self.make_txout(1.1*COIN)
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tx1a = CTransaction([CTxIn(tx0_outpoint, nSequence=0)],
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[CTxOut(1*COIN, CScript([b'a']))])
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tx1a_txid = self.proxy.sendrawtransaction(tx1a, True)
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# Should fail because we haven't changed the fee
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tx1b = CTransaction([CTxIn(tx0_outpoint, nSequence=0)],
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[CTxOut(1*COIN, CScript([b'b']))])
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try:
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tx1b_txid = self.proxy.sendrawtransaction(tx1b, True)
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except bitcoin.rpc.JSONRPCException as exp:
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self.assertEqual(exp.error['code'], -26) # insufficient fee
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else:
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self.fail()
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# Extra 0.1 BTC fee
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tx1b = CTransaction([CTxIn(tx0_outpoint, nSequence=0)],
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[CTxOut(0.9*COIN, CScript([b'b']))])
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tx1b_txid = self.proxy.sendrawtransaction(tx1b, True)
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# tx1a is in fact replaced
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with self.assertRaises(IndexError):
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self.proxy.getrawtransaction(tx1a_txid)
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self.assertEqual(tx1b, self.proxy.getrawtransaction(tx1b_txid))
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def test_doublespend_chain(self):
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"""Doublespend of a long chain"""
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initial_nValue = 50*COIN
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tx0_outpoint = self.make_txout(initial_nValue)
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prevout = tx0_outpoint
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remaining_value = initial_nValue
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chain_txids = []
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while remaining_value > 10*COIN:
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remaining_value -= 1*COIN
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tx = CTransaction([CTxIn(prevout, nSequence=0)],
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[CTxOut(remaining_value, CScript([1]))])
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txid = self.proxy.sendrawtransaction(tx, True)
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chain_txids.append(txid)
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prevout = COutPoint(txid, 0)
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# Whether the double-spend is allowed is evaluated by including all
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# child fees - 40 BTC - so this attempt is rejected.
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dbl_tx = CTransaction([CTxIn(tx0_outpoint, nSequence=0)],
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[CTxOut(initial_nValue - 30*COIN, CScript([1]))])
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try:
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self.proxy.sendrawtransaction(dbl_tx, True)
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except bitcoin.rpc.JSONRPCException as exp:
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self.assertEqual(exp.error['code'], -26) # insufficient fee
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else:
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self.fail()
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# Accepted with sufficient fee
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dbl_tx = CTransaction([CTxIn(tx0_outpoint, nSequence=0)],
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[CTxOut(1*COIN, CScript([1]))])
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self.proxy.sendrawtransaction(dbl_tx, True)
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for doublespent_txid in chain_txids:
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with self.assertRaises(IndexError):
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self.proxy.getrawtransaction(doublespent_txid)
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def test_doublespend_tree(self):
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"""Doublespend of a big tree of transactions"""
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initial_nValue = 50*COIN
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tx0_outpoint = self.make_txout(initial_nValue)
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def branch(prevout, initial_value, max_txs, *, tree_width=5, fee=0.0001*COIN, _total_txs=None):
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if _total_txs is None:
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_total_txs = [0]
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if _total_txs[0] >= max_txs:
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return
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txout_value = (initial_value - fee) // tree_width
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if txout_value < fee:
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return
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vout = [CTxOut(txout_value, CScript([i+1]))
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for i in range(tree_width)]
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tx = CTransaction([CTxIn(prevout, nSequence=0)],
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vout)
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self.assertTrue(len(tx.serialize()) < 100000)
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txid = self.proxy.sendrawtransaction(tx, True)
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yield tx
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_total_txs[0] += 1
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for i, txout in enumerate(tx.vout):
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yield from branch(COutPoint(txid, i), txout_value,
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max_txs,
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tree_width=tree_width, fee=fee,
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_total_txs=_total_txs)
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fee = 0.0001*COIN
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n = MAX_REPLACEMENT_LIMIT
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tree_txs = list(branch(tx0_outpoint, initial_nValue, n, fee=fee))
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self.assertEqual(len(tree_txs), n)
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# Attempt double-spend, will fail because too little fee paid
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dbl_tx = CTransaction([CTxIn(tx0_outpoint, nSequence=0)],
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[CTxOut(initial_nValue - fee*n, CScript([1]))])
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try:
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self.proxy.sendrawtransaction(dbl_tx, True)
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except bitcoin.rpc.JSONRPCException as exp:
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self.assertEqual(exp.error['code'], -26) # insufficient fee
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else:
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self.fail()
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# 1 BTC fee is enough
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dbl_tx = CTransaction([CTxIn(tx0_outpoint, nSequence=0)],
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[CTxOut(initial_nValue - fee*n - 1*COIN, CScript([1]))])
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self.proxy.sendrawtransaction(dbl_tx, True)
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for tx in tree_txs:
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with self.assertRaises(IndexError):
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self.proxy.getrawtransaction(tx.GetHash())
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# Try again, but with more total transactions than the "max txs
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# double-spent at once" anti-DoS limit.
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for n in (MAX_REPLACEMENT_LIMIT, MAX_REPLACEMENT_LIMIT*2):
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fee = 0.0001*COIN
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tx0_outpoint = self.make_txout(initial_nValue)
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tree_txs = list(branch(tx0_outpoint, initial_nValue, n, fee=fee))
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self.assertEqual(len(tree_txs), n)
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dbl_tx = CTransaction([CTxIn(tx0_outpoint, nSequence=0)],
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[CTxOut(initial_nValue - fee*n, CScript([1]))])
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try:
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self.proxy.sendrawtransaction(dbl_tx, True)
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except bitcoin.rpc.JSONRPCException as exp:
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self.assertEqual(exp.error['code'], -26)
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else:
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self.fail()
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for tx in tree_txs:
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self.proxy.getrawtransaction(tx.GetHash())
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def test_replacement_feeperkb(self):
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"""Replacement requires overall fee-per-KB to be higher"""
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tx0_outpoint = self.make_txout(1.1*COIN)
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tx1a = CTransaction([CTxIn(tx0_outpoint, nSequence=0)],
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[CTxOut(1*COIN, CScript([b'a']))])
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tx1a_txid = self.proxy.sendrawtransaction(tx1a, True)
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# Higher fee, but the fee per KB is much lower, so the replacement is
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# rejected.
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tx1b = CTransaction([CTxIn(tx0_outpoint, nSequence=0)],
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[CTxOut(0.001*COIN,
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CScript([b'a'*999000]))])
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try:
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tx1b_txid = self.proxy.sendrawtransaction(tx1b, True)
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except bitcoin.rpc.JSONRPCException as exp:
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self.assertEqual(exp.error['code'], -26) # insufficient fee
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else:
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self.fail()
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def test_spends_of_conflicting_outputs(self):
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"""Replacements that spend conflicting tx outputs are rejected"""
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utxo1 = self.make_txout(1.2*COIN)
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utxo2 = self.make_txout(3.0*COIN)
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tx1a = CTransaction([CTxIn(utxo1, nSequence=0)],
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[CTxOut(1.1*COIN, CScript([b'a']))])
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tx1a_txid = self.proxy.sendrawtransaction(tx1a, True)
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# Direct spend an output of the transaction we're replacing.
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tx2 = CTransaction([CTxIn(utxo1, nSequence=0), CTxIn(utxo2, nSequence=0),
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CTxIn(COutPoint(tx1a_txid, 0), nSequence=0)],
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tx1a.vout)
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try:
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tx2_txid = self.proxy.sendrawtransaction(tx2, True)
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except bitcoin.rpc.JSONRPCException as exp:
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self.assertEqual(exp.error['code'], -26)
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else:
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self.fail()
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# Spend tx1a's output to test the indirect case.
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tx1b = CTransaction([CTxIn(COutPoint(tx1a_txid, 0), nSequence=0)],
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[CTxOut(1.0*COIN, CScript([b'a']))])
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tx1b_txid = self.proxy.sendrawtransaction(tx1b, True)
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tx2 = CTransaction([CTxIn(utxo1, nSequence=0), CTxIn(utxo2, nSequence=0),
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CTxIn(COutPoint(tx1b_txid, 0))],
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tx1a.vout)
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try:
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tx2_txid = self.proxy.sendrawtransaction(tx2, True)
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except bitcoin.rpc.JSONRPCException as exp:
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self.assertEqual(exp.error['code'], -26)
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else:
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self.fail()
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if __name__ == '__main__':
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unittest.main()

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