test: fix "tx-size-small" errors after default address change

Addresses #17043, affects RBF and BIP68 functional tests.

The "tx-size-small" policy rule rejects transactions with a non-witness size of
smaller than 82 bytes (see src/validation.cpp:MemPoolAccept::PreChecks(...)),
which corresponds to a transaction with 1 segwit input and 1 P2WPKH output.

Through the default address change, the created test transactions have segwit
inputs now and sending to short scriptPubKeys might violate this rule. By
bumping the dummy scriptPubKey size to 22 bytes (= the size of a P2WPKH
scriptPubKey), on all occurences the problem is solved.

The dummy scriptPubKey has the format:
    21 <21-byte-long string of 'a' or 1s>

former commit messages, now squashed:
test: rbf, bip68: use constant DUMMY_P2WPKH_SCRIPT for bumped scriptPubKey
test: rbf, bip68: use constant DUMMY_P2WPKH_SCRIPT for dummy scriptPubKeys (b'a' * 35)
test: rbf, bip68: comment DUMMY_P2WPKH_SCRIPT constant, put into common (new) module

1 files changed, 10 insertions, 11 deletions

diff --git a/test/functional/feature_bip68_sequence.py b/test/functional/feature_bip68_sequence.py
index 677362756c..682a00ff4d 100755
--- a/test/functional/feature_bip68_sequence.py
+++ b/test/functional/feature_bip68_sequence.py
@@ -8,7 +8,6 @@ import time
 
 from test_framework.blocktools import create_block, create_coinbase, add_witness_commitment
 from test_framework.messages import COIN, COutPoint, CTransaction, CTxIn, CTxOut, FromHex, ToHex
-from test_framework.script import CScript
 from test_framework.test_framework import BitcoinTestFramework
 from test_framework.util import (
     assert_equal,
@@ -17,6 +16,7 @@ from test_framework.util import (
     satoshi_round,
     softfork_active,
 )
+from test_framework.script_util import DUMMY_P2WPKH_SCRIPT
 
 SEQUENCE_LOCKTIME_DISABLE_FLAG = (1<<31)
 SEQUENCE_LOCKTIME_TYPE_FLAG = (1<<22) # this means use time (0 means height)
@@ -29,10 +29,9 @@ NOT_FINAL_ERROR = "non-BIP68-final (code 64)"
 class BIP68Test(BitcoinTestFramework):
     def set_test_params(self):
         self.num_nodes = 2
-        # TODO remove output type argument and fix resulting "tx-size-small" errors
         self.extra_args = [
-            ["-acceptnonstdtxn=1", "-addresstype=p2sh-segwit"],
-            ["-acceptnonstdtxn=0", "-addresstype=p2sh-segwit"],
+            ["-acceptnonstdtxn=1"],
+            ["-acceptnonstdtxn=0"],
         ]
 
     def skip_test_if_missing_module(self):
@@ -85,7 +84,7 @@ class BIP68Test(BitcoinTestFramework):
         # input to mature.
         sequence_value = SEQUENCE_LOCKTIME_DISABLE_FLAG | 1
         tx1.vin = [CTxIn(COutPoint(int(utxo["txid"], 16), utxo["vout"]), nSequence=sequence_value)]
-        tx1.vout = [CTxOut(value, CScript([b'a']))]
+        tx1.vout = [CTxOut(value, DUMMY_P2WPKH_SCRIPT)]
 
         tx1_signed = self.nodes[0].signrawtransactionwithwallet(ToHex(tx1))["hex"]
         tx1_id = self.nodes[0].sendrawtransaction(tx1_signed)
@@ -97,7 +96,7 @@ class BIP68Test(BitcoinTestFramework):
         tx2.nVersion = 2
         sequence_value = sequence_value & 0x7fffffff
         tx2.vin = [CTxIn(COutPoint(tx1_id, 0), nSequence=sequence_value)]
-        tx2.vout = [CTxOut(int(value - self.relayfee * COIN), CScript([b'a' * 35]))]
+        tx2.vout = [CTxOut(int(value - self.relayfee * COIN), DUMMY_P2WPKH_SCRIPT)]
         tx2.rehash()
 
         assert_raises_rpc_error(-26, NOT_FINAL_ERROR, self.nodes[0].sendrawtransaction, ToHex(tx2))
@@ -192,7 +191,7 @@ class BIP68Test(BitcoinTestFramework):
                 value += utxos[j]["amount"]*COIN
             # Overestimate the size of the tx - signatures should be less than 120 bytes, and leave 50 for the output
             tx_size = len(ToHex(tx))//2 + 120*num_inputs + 50
-            tx.vout.append(CTxOut(int(value-self.relayfee*tx_size*COIN/1000), CScript([b'a'])))
+            tx.vout.append(CTxOut(int(value-self.relayfee*tx_size*COIN/1000), DUMMY_P2WPKH_SCRIPT))
             rawtx = self.nodes[0].signrawtransactionwithwallet(ToHex(tx))["hex"]
 
             if (using_sequence_locks and not should_pass):
@@ -221,7 +220,7 @@ class BIP68Test(BitcoinTestFramework):
         tx2 = CTransaction()
         tx2.nVersion = 2
         tx2.vin = [CTxIn(COutPoint(tx1.sha256, 0), nSequence=0)]
-        tx2.vout = [CTxOut(int(tx1.vout[0].nValue - self.relayfee*COIN), CScript([b'a']))]
+        tx2.vout = [CTxOut(int(tx1.vout[0].nValue - self.relayfee*COIN), DUMMY_P2WPKH_SCRIPT)]
         tx2_raw = self.nodes[0].signrawtransactionwithwallet(ToHex(tx2))["hex"]
         tx2 = FromHex(tx2, tx2_raw)
         tx2.rehash()
@@ -239,7 +238,7 @@ class BIP68Test(BitcoinTestFramework):
             tx = CTransaction()
             tx.nVersion = 2
             tx.vin = [CTxIn(COutPoint(orig_tx.sha256, 0), nSequence=sequence_value)]
-            tx.vout = [CTxOut(int(orig_tx.vout[0].nValue - relayfee * COIN), CScript([b'a' * 35]))]
+            tx.vout = [CTxOut(int(orig_tx.vout[0].nValue - relayfee * COIN), DUMMY_P2WPKH_SCRIPT)]
             tx.rehash()
 
             if (orig_tx.hash in node.getrawmempool()):
@@ -352,7 +351,7 @@ class BIP68Test(BitcoinTestFramework):
         tx2 = CTransaction()
         tx2.nVersion = 1
         tx2.vin = [CTxIn(COutPoint(tx1.sha256, 0), nSequence=0)]
-        tx2.vout = [CTxOut(int(tx1.vout[0].nValue - self.relayfee*COIN), CScript([b'a']))]
+        tx2.vout = [CTxOut(int(tx1.vout[0].nValue - self.relayfee*COIN), DUMMY_P2WPKH_SCRIPT)]
 
         # sign tx2
         tx2_raw = self.nodes[0].signrawtransactionwithwallet(ToHex(tx2))["hex"]
@@ -367,7 +366,7 @@ class BIP68Test(BitcoinTestFramework):
         tx3 = CTransaction()
         tx3.nVersion = 2
         tx3.vin = [CTxIn(COutPoint(tx2.sha256, 0), nSequence=sequence_value)]
-        tx3.vout = [CTxOut(int(tx2.vout[0].nValue - self.relayfee * COIN), CScript([b'a' * 35]))]
+        tx3.vout = [CTxOut(int(tx2.vout[0].nValue - self.relayfee * COIN), DUMMY_P2WPKH_SCRIPT)]
         tx3.rehash()
 
         assert_raises_rpc_error(-26, NOT_FINAL_ERROR, self.nodes[0].sendrawtransaction, ToHex(tx3))