test: MiniWallet: respect fee_rate for target_weight, use in mempool_limit.py

Author: theStack

test/functional/mempool_limit.py

@@ -59,7 +59,7 @@ def test_rbf_carveout_disallowed(self):
         mempoolmin_feerate = node.getmempoolinfo()["mempoolminfee"]
         tx_A = self.wallet.send_self_transfer(
             from_node=node,
-            fee=(mempoolmin_feerate / 1000) * (A_weight // 4) + Decimal('0.000001'),
+            fee_rate=mempoolmin_feerate,
             target_weight=A_weight,
             utxo_to_spend=rbf_utxo,
             confirmed_only=True
@@ -77,7 +77,7 @@ def test_rbf_carveout_disallowed(self):
         non_cpfp_carveout_weight = 40001 # EXTRA_DESCENDANT_TX_SIZE_LIMIT + 1
         tx_C = self.wallet.create_self_transfer(
             target_weight=non_cpfp_carveout_weight,
-            fee = (mempoolmin_feerate / 1000) * (non_cpfp_carveout_weight // 4) + Decimal('0.000001'),
+            fee_rate=mempoolmin_feerate,
             utxo_to_spend=tx_B["new_utxo"],
             confirmed_only=True
         )
@@ -109,7 +109,7 @@ def test_mid_package_eviction(self):
         # happen in the middle of package evaluation, as it can invalidate the coins cache.
         mempool_evicted_tx = self.wallet.send_self_transfer(
             from_node=node,
-            fee=(mempoolmin_feerate / 1000) * (evicted_weight // 4) + Decimal('0.000001'),
+            fee_rate=mempoolmin_feerate,
             target_weight=evicted_weight,
             confirmed_only=True
         )
@@ -135,11 +135,11 @@ def test_mid_package_eviction(self):
         parent_weight = 100000
         num_big_parents = 3
         assert_greater_than(parent_weight * num_big_parents, current_info["maxmempool"] - current_info["bytes"])
-        parent_fee = (100 * mempoolmin_feerate / 1000) * (parent_weight // 4)
+        parent_feerate = 100 * mempoolmin_feerate
 
         big_parent_txids = []
         for i in range(num_big_parents):
-            parent = self.wallet.create_self_transfer(fee=parent_fee, target_weight=parent_weight, confirmed_only=True)
+            parent = self.wallet.create_self_transfer(fee_rate=parent_feerate, target_weight=parent_weight, confirmed_only=True)
             parent_utxos.append(parent["new_utxo"])
             package_hex.append(parent["hex"])
             big_parent_txids.append(parent["txid"])
@@ -314,18 +314,20 @@ def run_test(self):
         target_weight_each = 200000
         assert_greater_than(target_weight_each * 2, node.getmempoolinfo()["maxmempool"] - node.getmempoolinfo()["bytes"])
         # Should be a true CPFP: parent's feerate is just below mempool min feerate
-        parent_fee = (mempoolmin_feerate / 1000) * (target_weight_each // 4) - Decimal("0.00001")
+        parent_feerate = mempoolmin_feerate - Decimal("0.000001")  # 0.1 sats/vbyte below min feerate
         # Parent + child is above mempool minimum feerate
-        child_fee = (worst_feerate_btcvb) * (target_weight_each // 4) - Decimal("0.00001")
+        child_feerate = (worst_feerate_btcvb * 1000) - Decimal("0.000001")  # 0.1 sats/vbyte below worst feerate
         # However, when eviction is triggered, these transactions should be at the bottom.
         # This assertion assumes parent and child are the same size.
         miniwallet.rescan_utxos()
-        tx_parent_just_below = miniwallet.create_self_transfer(fee=parent_fee, target_weight=target_weight_each)
-        tx_child_just_above = miniwallet.create_self_transfer(utxo_to_spend=tx_parent_just_below["new_utxo"], fee=child_fee, target_weight=target_weight_each)
+        tx_parent_just_below = miniwallet.create_self_transfer(fee_rate=parent_feerate, target_weight=target_weight_each)
+        tx_child_just_above = miniwallet.create_self_transfer(utxo_to_spend=tx_parent_just_below["new_utxo"], fee_rate=child_feerate, target_weight=target_weight_each)
         # This package ranks below the lowest descendant package in the mempool
-        assert_greater_than(worst_feerate_btcvb, (parent_fee + child_fee) / (tx_parent_just_below["tx"].get_vsize() + tx_child_just_above["tx"].get_vsize()))
-        assert_greater_than(mempoolmin_feerate, (parent_fee) / (tx_parent_just_below["tx"].get_vsize()))
-        assert_greater_than((parent_fee + child_fee) / (tx_parent_just_below["tx"].get_vsize() + tx_child_just_above["tx"].get_vsize()), mempoolmin_feerate / 1000)
+        package_fee = tx_parent_just_below["fee"] + tx_child_just_above["fee"]
+        package_vsize = tx_parent_just_below["tx"].get_vsize() + tx_child_just_above["tx"].get_vsize()
+        assert_greater_than(worst_feerate_btcvb, package_fee / package_vsize)
+        assert_greater_than(mempoolmin_feerate, tx_parent_just_below["fee"] / (tx_parent_just_below["tx"].get_vsize()))
+        assert_greater_than(package_fee / package_vsize, mempoolmin_feerate / 1000)
         res = node.submitpackage([tx_parent_just_below["hex"], tx_child_just_above["hex"]])
         for wtxid in [tx_parent_just_below["wtxid"], tx_child_just_above["wtxid"]]:
             assert_equal(res["tx-results"][wtxid]["error"], "mempool full")

test/functional/test_framework/wallet.py

@@ -7,6 +7,7 @@
 from copy import deepcopy
 from decimal import Decimal
 from enum import Enum
+import math
 from typing import (
     Any,
     Optional,
@@ -34,6 +35,7 @@
     CTxOut,
     hash256,
     ser_compact_size,
+    WITNESS_SCALE_FACTOR,
 )
 from test_framework.script import (
     CScript,
@@ -54,6 +56,7 @@
 from test_framework.util import (
     assert_equal,
     assert_greater_than_or_equal,
+    get_fee,
 )
 from test_framework.wallet_util import generate_keypair
 
@@ -372,6 +375,10 @@ def create_self_transfer(
             vsize = Decimal(168)  # P2PK (73 bytes scriptSig + 35 bytes scriptPubKey + 60 bytes other)
         else:
             assert False
+        if target_weight and not fee:  # respect fee_rate if target weight is passed
+            # the actual weight might be off by 3 WUs, so calculate based on that (see self._bulk_tx)
+            max_actual_weight = target_weight + 3
+            fee = get_fee(math.ceil(max_actual_weight / WITNESS_SCALE_FACTOR), fee_rate)
         send_value = utxo_to_spend["value"] - (fee or (fee_rate * vsize / 1000))
 
         # create tx