test: refactor: use Satoshis for fees in mempool_package_limits.py

This avoids having to convert from BTC to Sats and needs less imports.
Also specify the tx's target size in vsize rather than in weight, which
allows us to specify the fee-rate by a simple multiplication, rather
than having another magic number for it.

Author: theStack

test/functional/mempool_package_limits.py

@@ -3,20 +3,17 @@
 # Distributed under the MIT software license, see the accompanying
 # file COPYING or http://www.opensource.org/licenses/mit-license.php.
 """Test logic for limiting mempool and package ancestors/descendants."""
-
-from decimal import Decimal
-
 from test_framework.blocktools import COINBASE_MATURITY
-from test_framework.test_framework import BitcoinTestFramework
 from test_framework.messages import (
-    COIN,
     WITNESS_SCALE_FACTOR,
 )
+from test_framework.test_framework import BitcoinTestFramework
 from test_framework.util import (
     assert_equal,
 )
 from test_framework.wallet import MiniWallet
 
+
 class MempoolPackageLimitsTest(BitcoinTestFramework):
     def set_test_params(self):
         self.num_nodes = 1
@@ -304,8 +301,9 @@ def test_anc_size_limits(self):
         node = self.nodes[0]
         assert_equal(0, node.getmempoolinfo()["size"])
         parent_utxos = []
-        target_weight = WITNESS_SCALE_FACTOR * 1000 * 30 # 30KvB
-        high_fee = Decimal("0.003") # 10 sats/vB
+        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):
@@ -314,7 +312,7 @@ def test_anc_size_limits(self):
             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=int(high_fee * COIN), target_weight=target_weight)
+        pc_tx = self.wallet.create_self_transfer_multi(utxos_to_spend=parent_utxos, fee_per_output=high_fee, target_weight=target_weight)
 
         # Package transaction D
         pd_tx = self.wallet.create_self_transfer(utxo_to_spend=pc_tx["new_utxos"][0], target_weight=target_weight)
@@ -329,7 +327,7 @@ def test_anc_size_limits(self):
         assert all([res["allowed"] for res in node.testmempoolaccept(rawtxs=[pc_tx["hex"], pd_tx["hex"]])])
 
     def test_desc_size_limits(self):
-        """Create 3 mempool transactions and 2 package transactions (25KvB each):
+        """Create 3 mempool transactions and 2 package transactions (21KvB each):
               Ma
              ^ ^
             Mb  Mc
@@ -340,11 +338,12 @@ def test_desc_size_limits(self):
         """
         node = self.nodes[0]
         assert_equal(0, node.getmempoolinfo()["size"])
-        target_weight = 21 * 1000 * WITNESS_SCALE_FACTOR
-        high_fee = Decimal("0.0021") # 10 sats/vB
+        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=int(high_fee / 2 * COIN), target_weight=target_weight)
+        ma_tx = self.wallet.create_self_transfer_multi(num_outputs=2, fee_per_output=high_fee // 2, target_weight=target_weight)
         self.wallet.sendrawtransaction(from_node=node, tx_hex=ma_tx["hex"])
 
         package_hex = []
@@ -367,5 +366,6 @@ def test_desc_size_limits(self):
         self.generate(node, 1)
         assert all([res["allowed"] for res in node.testmempoolaccept(rawtxs=package_hex)])
 
+
 if __name__ == "__main__":
     MempoolPackageLimitsTest().main()