Merge #19800: test: Mockwallet

fa188c9 test: Use MiniWalet in p2p_feefilter (MarcoFalke)
fa39c62 test: inline hashToHex (MarcoFalke)

Pull request description:

  This introduces a minimalistic test wallet, which can be used as a drop in replacement for the Bitcoin Core wallet to create dummy transactions with a given fee rate.

ACKs for top commit:
  jnewbery:
    utACK fa188c9

Tree-SHA512: 0aad9cb14eea4f0055bd6a47cc8c8f82a16941b152598c3bf1e083aae84cca4ffa23f0b854a362a68be1b917deba1b5ec7c0207b63b0805d747ba9a7d1d82efe

Author: MarcoFalke

test/functional/p2p_feefilter.py

@@ -10,10 +10,7 @@
 from test_framework.p2p import P2PInterface, p2p_lock
 from test_framework.test_framework import BitcoinTestFramework
 from test_framework.util import assert_equal
-
-
-def hashToHex(hash):
-    return format(hash, '064x')
+from test_framework.wallet import MiniWallet
 
 
 class FeefilterConn(P2PInterface):
@@ -35,7 +32,7 @@ def __init__(self):
     def on_inv(self, message):
         for i in message.inv:
             if (i.type == MSG_TX) or (i.type == MSG_WTX):
-                self.txinvs.append(hashToHex(i.hash))
+                self.txinvs.append('{:064x}'.format(i.hash))
 
     def wait_for_invs_to_match(self, invs_expected):
         invs_expected.sort()
@@ -61,9 +58,6 @@ def set_test_params(self):
             "[email protected]",
         ]] * self.num_nodes
 
-    def skip_test_if_missing_module(self):
-        self.skip_if_no_wallet()
-
     def run_test(self):
         self.test_feefilter_forcerelay()
         self.test_feefilter()
@@ -83,27 +77,28 @@ def test_feefilter_forcerelay(self):
     def test_feefilter(self):
         node1 = self.nodes[1]
         node0 = self.nodes[0]
+        miniwallet = MiniWallet(node1)
+        # Add enough mature utxos to the wallet, so that all txs spend confirmed coins
+        miniwallet.generate(5)
+        node1.generate(100)
 
         conn = self.nodes[0].add_p2p_connection(TestP2PConn())
 
         self.log.info("Test txs paying 0.2 sat/byte are received by test connection")
-        node1.settxfee(Decimal("0.00000200"))
-        txids = [node1.sendtoaddress(node1.getnewaddress(), 1) for _ in range(3)]
+        txids = [miniwallet.send_self_transfer(fee_rate=Decimal('0.00000200'), from_node=node1)['wtxid'] for _ in range(3)]
         conn.wait_for_invs_to_match(txids)
         conn.clear_invs()
 
         # Set a fee filter of 0.15 sat/byte on test connection
         conn.send_and_ping(msg_feefilter(150))
 
         self.log.info("Test txs paying 0.15 sat/byte are received by test connection")
-        node1.settxfee(Decimal("0.00000150"))
-        txids = [node1.sendtoaddress(node1.getnewaddress(), 1) for _ in range(3)]
+        txids = [miniwallet.send_self_transfer(fee_rate=Decimal('0.00000150'), from_node=node1)['wtxid'] for _ in range(3)]
         conn.wait_for_invs_to_match(txids)
         conn.clear_invs()
 
         self.log.info("Test txs paying 0.1 sat/byte are no longer received by test connection")
-        node1.settxfee(Decimal("0.00000100"))
-        [node1.sendtoaddress(node1.getnewaddress(), 1) for _ in range(3)]
+        txids = [miniwallet.send_self_transfer(fee_rate=Decimal('0.00000100'), from_node=node1)['wtxid'] for _ in range(3)]
         self.sync_mempools()  # must be sure node 0 has received all txs
 
         # Send one transaction from node0 that should be received, so that we
@@ -113,14 +108,13 @@ def test_feefilter(self):
         # to 35 entries in an inv, which means that when this next transaction
         # is eligible for relay, the prior transactions from node1 are eligible
         # as well.
-        node0.settxfee(Decimal("0.00020000"))
-        txids = [node0.sendtoaddress(node0.getnewaddress(), 1)]
+        txids = [miniwallet.send_self_transfer(fee_rate=Decimal('0.00020000'), from_node=node0)['wtxid'] for _ in range(3)]
         conn.wait_for_invs_to_match(txids)
         conn.clear_invs()
 
         self.log.info("Remove fee filter and check txs are received again")
         conn.send_and_ping(msg_feefilter(0))
-        txids = [node1.sendtoaddress(node1.getnewaddress(), 1) for _ in range(3)]
+        txids = [miniwallet.send_self_transfer(fee_rate=Decimal('0.00020000'), from_node=node1)['wtxid'] for _ in range(3)]
         conn.wait_for_invs_to_match(txids)
         conn.clear_invs()
 

test/functional/test_framework/wallet.py

@@ -0,0 +1,64 @@
+#!/usr/bin/env python3
+# Copyright (c) 2020 The Bitcoin Core developers
+# Distributed under the MIT software license, see the accompanying
+# file COPYING or http://www.opensource.org/licenses/mit-license.php.
+"""A limited-functionality wallet, which may replace a real wallet in tests"""
+
+from decimal import Decimal
+from test_framework.address import ADDRESS_BCRT1_P2WSH_OP_TRUE
+from test_framework.messages import (
+    COIN,
+    COutPoint,
+    CTransaction,
+    CTxIn,
+    CTxInWitness,
+    CTxOut,
+)
+from test_framework.script import (
+    CScript,
+    OP_TRUE,
+)
+from test_framework.util import (
+    assert_equal,
+    hex_str_to_bytes,
+    satoshi_round,
+)
+
+
+class MiniWallet:
+    def __init__(self, test_node):
+        self._test_node = test_node
+        self._utxos = []
+        self._address = ADDRESS_BCRT1_P2WSH_OP_TRUE
+        self._scriptPubKey = hex_str_to_bytes(self._test_node.validateaddress(self._address)['scriptPubKey'])
+
+    def generate(self, num_blocks):
+        """Generate blocks with coinbase outputs to the internal address, and append the outputs to the internal list"""
+        blocks = self._test_node.generatetoaddress(num_blocks, self._address)
+        for b in blocks:
+            cb_tx = self._test_node.getblock(blockhash=b, verbosity=2)['tx'][0]
+            self._utxos.append({'txid': cb_tx['txid'], 'vout': 0, 'value': cb_tx['vout'][0]['value']})
+        return blocks
+
+    def send_self_transfer(self, *, fee_rate, from_node):
+        """Create and send a tx with the specified fee_rate. Fee may be exact or at most one satoshi higher than needed."""
+        self._utxos = sorted(self._utxos, key=lambda k: -k['value'])
+        largest_utxo = self._utxos.pop()  # Pick the largest utxo and hope it covers the fee
+        vsize = Decimal(96)
+        send_value = satoshi_round(largest_utxo['value'] - fee_rate * (vsize / 1000))
+        fee = largest_utxo['value'] - send_value
+        assert (send_value > 0)
+
+        tx = CTransaction()
+        tx.vin = [CTxIn(COutPoint(int(largest_utxo['txid'], 16), largest_utxo['vout']))]
+        tx.vout = [CTxOut(int(send_value * COIN), self._scriptPubKey)]
+        tx.wit.vtxinwit = [CTxInWitness()]
+        tx.wit.vtxinwit[0].scriptWitness.stack = [CScript([OP_TRUE])]
+        tx_hex = tx.serialize().hex()
+
+        txid = from_node.sendrawtransaction(tx_hex)
+        self._utxos.append({'txid': txid, 'vout': 0, 'value': send_value})
+        tx_info = from_node.getmempoolentry(txid)
+        assert_equal(tx_info['vsize'], vsize)
+        assert_equal(tx_info['fee'], fee)
+        return {'txid': txid, 'wtxid': tx_info['wtxid'], 'hex': tx_hex}