test: switch MiniWallet padding unit from weight to vsize

The weight unit is merely a consensus rule detail and is largely
irrelevant for fee-rate calculations and mempool policy rules (e.g. for
package relay and TRUC limits), so there doesn't seem to be any value of
using a granularity that we can't even guarantee to reach exactly
anyway.

Switch to the more natural unit of vsize instead, which simplifies both
the padding implementation and the current tests that take use of this
padding. The rather annoying multiplications by `WITNESS_SCALE_FACTOR`
can then be removed and weird-looking magic numbers like `4004` can be
replaced by numbers that are more connected to actual policy limit
constants from the codebase, e.g. `1001` for exceeding
`TRUC_CHILD_MAX_VSIZE` by one.

test/functional/mempool_package_limits.py

@@ -4,9 +4,6 @@
 # file COPYING or http://www.opensource.org/licenses/mit-license.php.
 """Test logic for limiting mempool and package ancestors/descendants."""
 from test_framework.blocktools import COINBASE_MATURITY
-from test_framework.messages import (
-    WITNESS_SCALE_FACTOR,
-)
 from test_framework.test_framework import BitcoinTestFramework
 from test_framework.util import (
     assert_equal,
@@ -290,19 +287,18 @@ class MempoolPackageLimitsTest(BitcoinTestFramework):
         parent_utxos = []
         target_vsize = 30_000
         high_fee = 10 * target_vsize  # 10 sats/vB
-        target_weight = target_vsize * WITNESS_SCALE_FACTOR
         self.log.info("Check that in-mempool and in-package ancestor size limits are calculated properly in packages")
         # Mempool transactions A and B
         for _ in range(2):
-            bulked_tx = self.wallet.create_self_transfer(target_weight=target_weight)
+            bulked_tx = self.wallet.create_self_transfer(target_vsize=target_vsize)
             self.wallet.sendrawtransaction(from_node=node, tx_hex=bulked_tx["hex"])
             parent_utxos.append(bulked_tx["new_utxo"])
 
         # Package transaction C
-        pc_tx = self.wallet.create_self_transfer_multi(utxos_to_spend=parent_utxos, fee_per_output=high_fee, target_weight=target_weight)
+        pc_tx = self.wallet.create_self_transfer_multi(utxos_to_spend=parent_utxos, fee_per_output=high_fee, target_vsize=target_vsize)
 
         # Package transaction D
-        pd_tx = self.wallet.create_self_transfer(utxo_to_spend=pc_tx["new_utxos"][0], target_weight=target_weight)
+        pd_tx = self.wallet.create_self_transfer(utxo_to_spend=pc_tx["new_utxos"][0], target_vsize=target_vsize)
 
         assert_equal(2, node.getmempoolinfo()["size"])
         return [pc_tx["hex"], pd_tx["hex"]]
@@ -321,20 +317,19 @@ class MempoolPackageLimitsTest(BitcoinTestFramework):
         node = self.nodes[0]
         target_vsize = 21_000
         high_fee = 10 * target_vsize  # 10 sats/vB
-        target_weight = target_vsize * WITNESS_SCALE_FACTOR
         self.log.info("Check that in-mempool and in-package descendant sizes are calculated properly in packages")
         # Top parent in mempool, Ma
-        ma_tx = self.wallet.create_self_transfer_multi(num_outputs=2, fee_per_output=high_fee // 2, target_weight=target_weight)
+        ma_tx = self.wallet.create_self_transfer_multi(num_outputs=2, fee_per_output=high_fee // 2, target_vsize=target_vsize)
         self.wallet.sendrawtransaction(from_node=node, tx_hex=ma_tx["hex"])
 
         package_hex = []
         for j in range(2): # Two legs (left and right)
             # Mempool transaction (Mb and Mc)
-            mempool_tx = self.wallet.create_self_transfer(utxo_to_spend=ma_tx["new_utxos"][j], target_weight=target_weight)
+            mempool_tx = self.wallet.create_self_transfer(utxo_to_spend=ma_tx["new_utxos"][j], target_vsize=target_vsize)
             self.wallet.sendrawtransaction(from_node=node, tx_hex=mempool_tx["hex"])
 
             # Package transaction (Pd and Pe)
-            package_tx = self.wallet.create_self_transfer(utxo_to_spend=mempool_tx["new_utxo"], target_weight=target_weight)
+            package_tx = self.wallet.create_self_transfer(utxo_to_spend=mempool_tx["new_utxo"], target_vsize=target_vsize)
             package_hex.append(package_tx["hex"])
 
         assert_equal(3, node.getmempoolinfo()["size"])