From 6ccc8fc067bf516cda7bc5d7d721945be5ac2003 Mon Sep 17 00:00:00 2001
From: Fabian Jahr <fjahr@protonmail.com>
Date: Thu, 14 Jan 2021 00:10:04 +0100
Subject: [PATCH] test: Add test for gettxoutsetinfo RPC with MuHash

---
 test/functional/feature_utxo_set_hash.py | 78 ++++++++++++++++++++++++
 test/functional/test_runner.py           |  1 +
 2 files changed, 79 insertions(+)
 create mode 100755 test/functional/feature_utxo_set_hash.py

diff --git a/test/functional/feature_utxo_set_hash.py b/test/functional/feature_utxo_set_hash.py
new file mode 100755
index 0000000000..a8e6a2e753
--- /dev/null
+++ b/test/functional/feature_utxo_set_hash.py
@@ -0,0 +1,78 @@
+#!/usr/bin/env python3
+# Copyright (c) 2020-2021 The Bitcoin Core developers
+# Distributed under the MIT software license, see the accompanying
+# file COPYING or http://www.opensource.org/licenses/mit-license.php.
+"""Test UTXO set hash value calculation in gettxoutsetinfo."""
+
+import struct
+
+from test_framework.blocktools import create_transaction
+from test_framework.messages import (
+    CBlock,
+    COutPoint,
+    FromHex,
+)
+from test_framework.muhash import MuHash3072
+from test_framework.test_framework import BitcoinTestFramework
+from test_framework.util import assert_equal
+
+class UTXOSetHashTest(BitcoinTestFramework):
+    def set_test_params(self):
+        self.num_nodes = 1
+        self.setup_clean_chain = True
+
+    def skip_test_if_missing_module(self):
+        self.skip_if_no_wallet()
+
+    def test_muhash_implementation(self):
+        self.log.info("Test MuHash implementation consistency")
+
+        node = self.nodes[0]
+
+        # Generate 100 blocks and remove the first since we plan to spend its
+        # coinbase
+        block_hashes = node.generate(100)
+        blocks = list(map(lambda block: FromHex(CBlock(), node.getblock(block, False)), block_hashes))
+        spending = blocks.pop(0)
+
+        # Create a spending transaction and mine a block which includes it
+        tx = create_transaction(node, spending.vtx[0].rehash(), node.getnewaddress(), amount=49)
+        txid = node.sendrawtransaction(hexstring=tx.serialize_with_witness().hex(), maxfeerate=0)
+
+        tx_block = node.generateblock(output=node.getnewaddress(), transactions=[txid])
+        blocks.append(FromHex(CBlock(), node.getblock(tx_block['hash'], False)))
+
+        # Serialize the outputs that should be in the UTXO set and add them to
+        # a MuHash object
+        muhash = MuHash3072()
+
+        for height, block in enumerate(blocks):
+            # The Genesis block coinbase is not part of the UTXO set and we
+            # spent the first mined block
+            height += 2
+
+            for tx in block.vtx:
+                for n, tx_out in enumerate(tx.vout):
+                    coinbase = 1 if not tx.vin[0].prevout.hash else 0
+
+                    # Skip witness commitment
+                    if (coinbase and n > 0):
+                        continue
+
+                    data = COutPoint(int(tx.rehash(), 16), n).serialize()
+                    data += struct.pack("<i", height * 2 + coinbase)
+                    data += tx_out.serialize()
+
+                    muhash.insert(data)
+
+        finalized = muhash.digest()
+        node_muhash = node.gettxoutsetinfo("muhash")['muhash']
+
+        assert_equal(finalized[::-1].hex(), node_muhash)
+
+    def run_test(self):
+        self.test_muhash_implementation()
+
+
+if __name__ == '__main__':
+    UTXOSetHashTest().main()
diff --git a/test/functional/test_runner.py b/test/functional/test_runner.py
index 9bbf862568..70e2029a10 100755
--- a/test/functional/test_runner.py
+++ b/test/functional/test_runner.py
@@ -202,6 +202,7 @@ BASE_SCRIPTS = [
     'feature_notifications.py',
     'rpc_getblockfilter.py',
     'rpc_invalidateblock.py',
+    'feature_utxo_set_hash.py',
     'feature_rbf.py',
     'mempool_packages.py',
     'mempool_package_onemore.py',