test: MiniWallet: fix tx padding (target_weight) for large sizes, improve accuracy

This commit is contained in:
Sebastian Falbesoner 2024-05-23 18:20:58 +02:00
parent ef44726918
commit c17550bc3a

View File

@ -33,10 +33,12 @@ from test_framework.messages import (
CTxInWitness,
CTxOut,
hash256,
ser_compact_size,
)
from test_framework.script import (
CScript,
LEAF_VERSION_TAPSCRIPT,
OP_1,
OP_NOP,
OP_RETURN,
OP_TRUE,
@ -119,13 +121,16 @@ class MiniWallet:
"""Pad a transaction with extra outputs until it reaches a target weight (or higher).
returns the tx
"""
tx.vout.append(CTxOut(nValue=0, scriptPubKey=CScript([OP_RETURN, b'a'])))
tx.vout.append(CTxOut(nValue=0, scriptPubKey=CScript([OP_RETURN])))
# determine number of needed padding bytes by converting weight difference to vbytes
dummy_vbytes = (target_weight - tx.get_weight() + 3) // 4
tx.vout[-1].scriptPubKey = CScript([OP_RETURN, b'a' * dummy_vbytes])
# Lower bound should always be off by at most 3
# compensate for the increase of the compact-size encoded script length
# (note that the length encoding of the unpadded output script needs one byte)
dummy_vbytes -= len(ser_compact_size(dummy_vbytes)) - 1
tx.vout[-1].scriptPubKey = CScript([OP_RETURN] + [OP_1] * dummy_vbytes)
# Actual weight should be at most 3 higher than target weight
assert_greater_than_or_equal(tx.get_weight(), target_weight)
# Higher bound should always be off by at most 3 + 12 weight (for encoding the length)
assert_greater_than_or_equal(target_weight + 15, tx.get_weight())
assert_greater_than_or_equal(target_weight + 3, tx.get_weight())
def get_balance(self):
return sum(u['value'] for u in self._utxos)