test: add test for fast rescan using block filters (top-up detection)

2 files changed, 103 insertions, 0 deletions

diff --git a/test/functional/test_runner.py b/test/functional/test_runner.py
index e20de8ea8e..e2c13a6705 100755
--- a/test/functional/test_runner.py
+++ b/test/functional/test_runner.py
@@ -136,6 +136,7 @@ BASE_SCRIPTS = [
     # vv Tests less than 30s vv
     'wallet_keypool_topup.py --legacy-wallet',
     'wallet_keypool_topup.py --descriptors',
+    'wallet_fast_rescan.py --descriptors',
     'feature_fee_estimation.py',
     'interface_zmq.py',
     'rpc_invalid_address_message.py',
diff --git a/test/functional/wallet_fast_rescan.py b/test/functional/wallet_fast_rescan.py
new file mode 100755
index 0000000000..3b8ae8eb92
--- /dev/null
+++ b/test/functional/wallet_fast_rescan.py
@@ -0,0 +1,102 @@
+#!/usr/bin/env python3
+# Copyright (c) 2022 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 that fast rescan using block filters for descriptor wallets detects
+   top-ups correctly and finds the same transactions than the slow variant."""
+import os
+from typing import List
+
+from test_framework.descriptors import descsum_create
+from test_framework.test_framework import BitcoinTestFramework
+from test_framework.test_node import TestNode
+from test_framework.util import assert_equal
+from test_framework.wallet import MiniWallet
+from test_framework.wallet_util import get_generate_key
+
+
+KEYPOOL_SIZE = 100   # smaller than default size to speed-up test
+NUM_DESCRIPTORS = 9  # number of descriptors (8 default ranged ones + 1 fixed non-ranged one)
+NUM_BLOCKS = 6       # number of blocks to mine
+
+
+class WalletFastRescanTest(BitcoinTestFramework):
+    def set_test_params(self):
+        self.num_nodes = 1
+        self.extra_args = [[f'-keypool={KEYPOOL_SIZE}', '-blockfilterindex=1']]
+
+    def skip_test_if_missing_module(self):
+        self.skip_if_no_wallet()
+        self.skip_if_no_sqlite()
+
+    def get_wallet_txids(self, node: TestNode, wallet_name: str) -> List[str]:
+        w = node.get_wallet_rpc(wallet_name)
+        txs = w.listtransactions('*', 1000000)
+        return [tx['txid'] for tx in txs]
+
+    def run_test(self):
+        node = self.nodes[0]
+        wallet = MiniWallet(node)
+        wallet.rescan_utxos()
+
+        self.log.info("Create descriptor wallet with backup")
+        WALLET_BACKUP_FILENAME = os.path.join(node.datadir, 'wallet.bak')
+        node.createwallet(wallet_name='topup_test', descriptors=True)
+        w = node.get_wallet_rpc('topup_test')
+        fixed_key = get_generate_key()
+        print(w.importdescriptors([{"desc": descsum_create(f"wpkh({fixed_key.privkey})"), "timestamp": "now"}]))
+        descriptors = w.listdescriptors()['descriptors']
+        assert_equal(len(descriptors), NUM_DESCRIPTORS)
+        w.backupwallet(WALLET_BACKUP_FILENAME)
+
+        self.log.info(f"Create txs sending to end range address of each descriptor, triggering top-ups")
+        for i in range(NUM_BLOCKS):
+            self.log.info(f"Block {i+1}/{NUM_BLOCKS}")
+            for desc_info in w.listdescriptors()['descriptors']:
+                if 'range' in desc_info:
+                    start_range, end_range = desc_info['range']
+                    addr = w.deriveaddresses(desc_info['desc'], [end_range, end_range])[0]
+                    spk = bytes.fromhex(w.getaddressinfo(addr)['scriptPubKey'])
+                    self.log.info(f"-> range [{start_range},{end_range}], last address {addr}")
+                else:
+                    spk = bytes.fromhex(fixed_key.p2wpkh_script)
+                    self.log.info(f"-> fixed non-range descriptor address {fixed_key.p2wpkh_addr}")
+                wallet.send_to(from_node=node, scriptPubKey=spk, amount=10000)
+            self.generate(node, 1)
+
+        self.log.info("Import wallet backup with block filter index")
+        with node.assert_debug_log(['fast variant using block filters']):
+            node.restorewallet('rescan_fast', WALLET_BACKUP_FILENAME)
+        txids_fast = self.get_wallet_txids(node, 'rescan_fast')
+
+        self.log.info("Import non-active descriptors with block filter index")
+        node.createwallet(wallet_name='rescan_fast_nonactive', descriptors=True, disable_private_keys=True, blank=True)
+        with node.assert_debug_log(['fast variant using block filters']):
+            w = node.get_wallet_rpc('rescan_fast_nonactive')
+            w.importdescriptors([{"desc": descriptor['desc'], "timestamp": 0} for descriptor in descriptors])
+        txids_fast_nonactive = self.get_wallet_txids(node, 'rescan_fast_nonactive')
+
+        self.restart_node(0, [f'-keypool={KEYPOOL_SIZE}', '-blockfilterindex=0'])
+        self.log.info("Import wallet backup w/o block filter index")
+        with node.assert_debug_log(['slow variant inspecting all blocks']):
+            node.restorewallet("rescan_slow", WALLET_BACKUP_FILENAME)
+        txids_slow = self.get_wallet_txids(node, 'rescan_slow')
+
+        self.log.info("Import non-active descriptors w/o block filter index")
+        node.createwallet(wallet_name='rescan_slow_nonactive', descriptors=True, disable_private_keys=True, blank=True)
+        with node.assert_debug_log(['slow variant inspecting all blocks']):
+            w = node.get_wallet_rpc('rescan_slow_nonactive')
+            w.importdescriptors([{"desc": descriptor['desc'], "timestamp": 0} for descriptor in descriptors])
+        txids_slow_nonactive = self.get_wallet_txids(node, 'rescan_slow_nonactive')
+
+        self.log.info("Verify that all rescans found the same txs in slow and fast variants")
+        assert_equal(len(txids_slow), NUM_DESCRIPTORS * NUM_BLOCKS)
+        assert_equal(len(txids_fast), NUM_DESCRIPTORS * NUM_BLOCKS)
+        assert_equal(len(txids_slow_nonactive), NUM_DESCRIPTORS * NUM_BLOCKS)
+        assert_equal(len(txids_fast_nonactive), NUM_DESCRIPTORS * NUM_BLOCKS)
+        assert_equal(sorted(txids_slow), sorted(txids_fast))
+        assert_equal(sorted(txids_slow_nonactive), sorted(txids_fast_nonactive))
+
+
+if __name__ == '__main__':
+    WalletFastRescanTest().main()