Merge bitcoin/bitcoin#28838: test: add assumeutxo wallet test

997b9a7 test: add assumeutxo wallet test (Sjors Provoost)

Pull request description:

  Extracted from #28616, this adds a (very) basic wallet test for assume utxo. It checks some circumstances where a backup can and can't be loaded.

ACKs for top commit:
  maflcko:
    lgtm ACK 997b9a7
  achow101:
    ACK 997b9a7
  theStack:
    Code-review ACK 997b9a7

Tree-SHA512: 69474e56c6a46bb4f30fc54f8e5844766ac2a5f8226bb0b168d11ae1e3d4eae58570c1f1b4cc2b2f6f51b5d0e055bbe2bbd11684265215e01d4eb81ab4b7b0bb

Author: achow101

test/functional/test_runner.py

@@ -343,6 +343,7 @@
     'feature_filelock.py',
     'feature_loadblock.py',
     'feature_assumeutxo.py',
+    'wallet_assumeutxo.py --descriptors',
     'p2p_dos_header_tree.py',
     'p2p_add_connections.py',
     'feature_bind_port_discover.py',

test/functional/wallet_assumeutxo.py

@@ -0,0 +1,164 @@
+#!/usr/bin/env python3
+# Copyright (c) 2023-present 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 for assumeutxo wallet related behavior.
+See feature_assumeutxo.py for background.
+
+## Possible test improvements
+
+- TODO: test import descriptors while background sync is in progress
+- TODO: test loading a wallet (backup) on a pruned node
+
+"""
+from test_framework.test_framework import BitcoinTestFramework
+from test_framework.util import (
+    assert_equal,
+    assert_raises_rpc_error,
+)
+
+START_HEIGHT = 199
+SNAPSHOT_BASE_HEIGHT = 299
+FINAL_HEIGHT = 399
+
+
+class AssumeutxoTest(BitcoinTestFramework):
+    def skip_test_if_missing_module(self):
+        self.skip_if_no_wallet()
+
+    def add_options(self, parser):
+        self.add_wallet_options(parser, legacy=False)
+
+    def set_test_params(self):
+        """Use the pregenerated, deterministic chain up to height 199."""
+        self.num_nodes = 2
+        self.rpc_timeout = 120
+        self.extra_args = [
+            [],
+            [],
+        ]
+
+    def setup_network(self):
+        """Start with the nodes disconnected so that one can generate a snapshot
+        including blocks the other hasn't yet seen."""
+        self.add_nodes(2)
+        self.start_nodes(extra_args=self.extra_args)
+
+    def run_test(self):
+        """
+        Bring up two (disconnected) nodes, mine some new blocks on the first,
+        and generate a UTXO snapshot.
+
+        Load the snapshot into the second, ensure it syncs to tip and completes
+        background validation when connected to the first.
+        """
+        n0 = self.nodes[0]
+        n1 = self.nodes[1]
+
+        # Mock time for a deterministic chain
+        for n in self.nodes:
+            n.setmocktime(n.getblockheader(n.getbestblockhash())['time'])
+
+        self.sync_blocks()
+
+        n0.createwallet('w')
+        w = n0.get_wallet_rpc("w")
+
+        # Generate a series of blocks that `n0` will have in the snapshot,
+        # but that n1 doesn't yet see. In order for the snapshot to activate,
+        # though, we have to ferry over the new headers to n1 so that it
+        # isn't waiting forever to see the header of the snapshot's base block
+        # while disconnected from n0.
+        for _ in range(100):
+            self.generate(n0, nblocks=1, sync_fun=self.no_op)
+            newblock = n0.getblock(n0.getbestblockhash(), 0)
+
+            # make n1 aware of the new header, but don't give it the block.
+            n1.submitheader(newblock)
+
+        # Ensure everyone is seeing the same headers.
+        for n in self.nodes:
+            assert_equal(n.getblockchaininfo()[
+                         "headers"], SNAPSHOT_BASE_HEIGHT)
+
+        w.backupwallet("backup_w.dat")
+
+        self.log.info("-- Testing assumeutxo")
+
+        assert_equal(n0.getblockcount(), SNAPSHOT_BASE_HEIGHT)
+        assert_equal(n1.getblockcount(), START_HEIGHT)
+
+        self.log.info(
+            f"Creating a UTXO snapshot at height {SNAPSHOT_BASE_HEIGHT}")
+        dump_output = n0.dumptxoutset('utxos.dat')
+
+        assert_equal(
+            dump_output['txoutset_hash'],
+            '61d9c2b29a2571a5fe285fe2d8554f91f93309666fc9b8223ee96338de25ff53')
+        assert_equal(dump_output['nchaintx'], 300)
+        assert_equal(n0.getblockchaininfo()["blocks"], SNAPSHOT_BASE_HEIGHT)
+
+        # Mine more blocks on top of the snapshot that n1 hasn't yet seen. This
+        # will allow us to test n1's sync-to-tip on top of a snapshot.
+        self.generate(n0, nblocks=100, sync_fun=self.no_op)
+
+        assert_equal(n0.getblockcount(), FINAL_HEIGHT)
+        assert_equal(n1.getblockcount(), START_HEIGHT)
+
+        assert_equal(n0.getblockchaininfo()["blocks"], FINAL_HEIGHT)
+
+        self.log.info(
+            f"Loading snapshot into second node from {dump_output['path']}")
+        loaded = n1.loadtxoutset(dump_output['path'])
+        assert_equal(loaded['coins_loaded'], SNAPSHOT_BASE_HEIGHT)
+        assert_equal(loaded['base_height'], SNAPSHOT_BASE_HEIGHT)
+
+        normal, snapshot = n1.getchainstates()["chainstates"]
+        assert_equal(normal['blocks'], START_HEIGHT)
+        assert_equal(normal.get('snapshot_blockhash'), None)
+        assert_equal(normal['validated'], True)
+        assert_equal(snapshot['blocks'], SNAPSHOT_BASE_HEIGHT)
+        assert_equal(snapshot['snapshot_blockhash'], dump_output['base_hash'])
+        assert_equal(snapshot['validated'], False)
+
+        assert_equal(n1.getblockchaininfo()["blocks"], SNAPSHOT_BASE_HEIGHT)
+
+        self.log.info("Backup can't be loaded during background sync")
+        assert_raises_rpc_error(-4, "Wallet loading failed. Error loading wallet. Wallet requires blocks to be downloaded, and software does not currently support loading wallets while blocks are being downloaded out of order when using assumeutxo snapshots. Wallet should be able to load successfully after node sync reaches height 299", n1.restorewallet, "w", "backup_w.dat")
+
+        PAUSE_HEIGHT = FINAL_HEIGHT - 40
+
+        self.log.info("Restarting node to stop at height %d", PAUSE_HEIGHT)
+        self.restart_node(1, extra_args=[
+            f"-stopatheight={PAUSE_HEIGHT}", *self.extra_args[1]])
+
+        # Finally connect the nodes and let them sync.
+        #
+        # Set `wait_for_connect=False` to avoid a race between performing connection
+        # assertions and the -stopatheight tripping.
+        self.connect_nodes(0, 1, wait_for_connect=False)
+
+        n1.wait_until_stopped(timeout=5)
+
+        self.log.info(
+            "Restarted node before snapshot validation completed, reloading...")
+        self.restart_node(1, extra_args=self.extra_args[1])
+
+        # TODO: inspect state of e.g. the wallet before reconnecting
+        self.connect_nodes(0, 1)
+
+        self.log.info(
+            f"Ensuring snapshot chain syncs to tip. ({FINAL_HEIGHT})")
+        self.wait_until(lambda: n1.getchainstates()[
+                        'chainstates'][-1]['blocks'] == FINAL_HEIGHT)
+        self.sync_blocks(nodes=(n0, n1))
+
+        self.log.info("Ensuring background validation completes")
+        self.wait_until(lambda: len(n1.getchainstates()['chainstates']) == 1)
+
+        self.log.info("Ensuring wallet can be restored from backup")
+        n1.restorewallet("w", "backup_w.dat")
+
+
+if __name__ == '__main__':
+    AssumeutxoTest().main()