test: introduce `get_weight()` helper for CTransaction

test/functional/feature_segwit.py

@@ -260,8 +260,8 @@ class SegWitTest(BitcoinTestFramework):
         assert_equal(int(self.nodes[0].getmempoolentry(txid1)["wtxid"], 16), tx1.calc_sha256(True))
 
         # Check that weight and vsize are properly reported in mempool entry (txid1)
-        assert_equal(self.nodes[0].getmempoolentry(txid1)["vsize"], (self.nodes[0].getmempoolentry(txid1)["weight"] + 3) // 4)
-        assert_equal(self.nodes[0].getmempoolentry(txid1)["weight"], len(tx1.serialize_without_witness())*3 + len(tx1.serialize_with_witness()))
+        assert_equal(self.nodes[0].getmempoolentry(txid1)["vsize"], tx1.get_vsize())
+        assert_equal(self.nodes[0].getmempoolentry(txid1)["weight"], tx1.get_weight())
 
         # Now create tx2, which will spend from txid1.
         tx = CTransaction()
@@ -276,8 +276,8 @@ class SegWitTest(BitcoinTestFramework):
         assert_equal(int(self.nodes[0].getmempoolentry(txid2)["wtxid"], 16), tx.calc_sha256(True))
 
         # Check that weight and vsize are properly reported in mempool entry (txid2)
-        assert_equal(self.nodes[0].getmempoolentry(txid2)["vsize"], (self.nodes[0].getmempoolentry(txid2)["weight"] + 3) // 4)
-        assert_equal(self.nodes[0].getmempoolentry(txid2)["weight"], len(tx.serialize_without_witness())*3 + len(tx.serialize_with_witness()))
+        assert_equal(self.nodes[0].getmempoolentry(txid2)["vsize"], tx.get_vsize())
+        assert_equal(self.nodes[0].getmempoolentry(txid2)["weight"], tx.get_weight())
 
         # Now create tx3, which will spend from txid2
         tx = CTransaction()
@@ -299,8 +299,8 @@ class SegWitTest(BitcoinTestFramework):
         assert_equal(int(self.nodes[0].getmempoolentry(txid3)["wtxid"], 16), tx.calc_sha256(True))
 
         # Check that weight and vsize are properly reported in mempool entry (txid3)
-        assert_equal(self.nodes[0].getmempoolentry(txid3)["vsize"], (self.nodes[0].getmempoolentry(txid3)["weight"] + 3) // 4)
-        assert_equal(self.nodes[0].getmempoolentry(txid3)["weight"], len(tx.serialize_without_witness())*3 + len(tx.serialize_with_witness()))
+        assert_equal(self.nodes[0].getmempoolentry(txid3)["vsize"], tx.get_vsize())
+        assert_equal(self.nodes[0].getmempoolentry(txid3)["weight"], tx.get_weight())
 
         # Mine a block to clear the gbt cache again.
         self.nodes[0].generate(1)

test/functional/p2p_segwit.py

@@ -4,7 +4,6 @@
 # file COPYING or http://www.opensource.org/licenses/mit-license.php.
 """Test segwit transactions and blocks on P2P network."""
 from decimal import Decimal
-import math
 import random
 import struct
 import time
@@ -1367,10 +1366,9 @@ class SegWitTest(BitcoinTestFramework):
         raw_tx = self.nodes[0].getrawtransaction(tx3.hash, 1)
         assert_equal(int(raw_tx["hash"], 16), tx3.calc_sha256(True))
         assert_equal(raw_tx["size"], len(tx3.serialize_with_witness()))
-        weight = len(tx3.serialize_with_witness()) + 3 * len(tx3.serialize_without_witness())
-        vsize = math.ceil(weight / 4)
+        vsize = tx3.get_vsize()
         assert_equal(raw_tx["vsize"], vsize)
-        assert_equal(raw_tx["weight"], weight)
+        assert_equal(raw_tx["weight"], tx3.get_weight())
         assert_equal(len(raw_tx["vin"][0]["txinwitness"]), 1)
         assert_equal(raw_tx["vin"][0]["txinwitness"][0], witness_program.hex())
         assert vsize != raw_tx["size"]

test/functional/test_framework/messages.py

@@ -590,12 +590,15 @@ class CTransaction:
                 return False
         return True
 
-    # Calculate the virtual transaction size using witness and non-witness
+    # Calculate the transaction weight using witness and non-witness
     # serialization size (does NOT use sigops).
-    def get_vsize(self):
+    def get_weight(self):
         with_witness_size = len(self.serialize_with_witness())
         without_witness_size = len(self.serialize_without_witness())
-        return math.ceil(((WITNESS_SCALE_FACTOR - 1) * without_witness_size + with_witness_size) / WITNESS_SCALE_FACTOR)
+        return (WITNESS_SCALE_FACTOR - 1) * without_witness_size + with_witness_size
+
+    def get_vsize(self):
+        return math.ceil(self.get_weight() / WITNESS_SCALE_FACTOR)
 
     def __repr__(self):
         return "CTransaction(nVersion=%i vin=%s vout=%s wit=%s nLockTime=%i)" \