test: add dumptxoutset RPC test

Author: jamesob

test/functional/rpc_dumptxoutset.py

@@ -0,0 +1,51 @@
+#!/usr/bin/env python3
+# Copyright (c) 2019 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 the generation of UTXO snapshots using `dumptxoutset`.
+"""
+from test_framework.test_framework import BitcoinTestFramework
+from test_framework.util import assert_equal, assert_raises_rpc_error
+
+import hashlib
+from pathlib import Path
+
+
+class DumptxoutsetTest(BitcoinTestFramework):
+    def set_test_params(self):
+        self.setup_clean_chain = True
+        self.num_nodes = 1
+
+    def run_test(self):
+        """Test a trivial usage of the dumptxoutset RPC command."""
+        node = self.nodes[0]
+        mocktime = node.getblockheader(node.getblockhash(0))['time'] + 1
+        node.setmocktime(mocktime)
+        node.generate(100)
+
+        FILENAME = 'txoutset.dat'
+        out = node.dumptxoutset(FILENAME)
+        expected_path = Path(node.datadir) / 'regtest' / FILENAME
+
+        assert expected_path.is_file()
+
+        assert_equal(out['coins_written'], 100)
+        assert_equal(out['base_height'], 100)
+        assert_equal(out['path'], str(expected_path))
+        # Blockhash should be deterministic based on mocked time.
+        assert_equal(
+            out['base_hash'],
+            '6fd417acba2a8738b06fee43330c50d58e6a725046c3d843c8dd7e51d46d1ed6')
+
+        with open(str(expected_path), 'rb') as f:
+            digest = hashlib.sha256(f.read()).hexdigest()
+            # UTXO snapshot hash should be deterministic based on mocked time.
+            assert_equal(
+                digest, 'be032e5f248264ba08e11099ac09dbd001f6f87ffc68bf0f87043d8146d50664')
+
+        # Specifying a path to an existing file will fail.
+        assert_raises_rpc_error(
+            -8, '{} already exists'.format(FILENAME),  node.dumptxoutset, FILENAME)
+
+if __name__ == '__main__':
+    DumptxoutsetTest().main()

test/functional/test_runner.py

@@ -190,6 +190,7 @@
     'rpc_uptime.py',
     'wallet_resendwallettransactions.py',
     'wallet_fallbackfee.py',
+    'rpc_dumptxoutset.py',
     'feature_minchainwork.py',
     'rpc_getblockstats.py',
     'wallet_create_tx.py',