test: add feature_asmap functional tests

to verify node behaviour and debug log when launching bitcoind in these cases:

1. `bitcoind` with no -asmap arg, using /16 prefix for IP bucketing

2. `bitcoind -asmap=<relative path>`, using the unit test skeleton asmap

3. `bitcoind -asmap/-asmap=` with no file specified, using the default asmap

4. `bitcoind -asmap` with no file specified, and a missing default asmap file

The tests are order-independent. The slowest test (missing default asmap file)
is placed last.

test/functional/feature_asmap.py

@@ -0,0 +1,83 @@
+#!/usr/bin/env python3
+# Copyright (c) 2020 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 asmap config argument for ASN-based IP bucketing.
+
+Verify node behaviour and debug log when launching bitcoind in these cases:
+
+1. `bitcoind` with no -asmap arg, using /16 prefix for IP bucketing
+
+2. `bitcoind -asmap=<relative path>`, using the unit test skeleton asmap
+
+3. `bitcoind -asmap/-asmap=` with no file specified, using the default asmap
+
+4. `bitcoind -asmap` with no file specified, and a missing default asmap file
+
+The tests are order-independent. The slowest test (missing default asmap file)
+is placed last.
+
+"""
+import os
+import shutil
+
+from test_framework.test_framework import BitcoinTestFramework
+
+DEFAULT_ASMAP_FILENAME = 'ip_asn.map' # defined in src/init.cpp
+ASMAP = '../../src/test/data/asmap.raw' # path to unit test skeleton asmap
+VERSION = 'fec61fa21a9f46f3b17bdcd660d7f4cd90b966aad3aec593c99b35f0aca15853'
+
+def expected_messages(filename):
+    return ['Opened asmap file "{}" (59 bytes) from disk.'.format(filename),
+            'Using asmap version {} for IP bucketing.'.format(VERSION)]
+
+class AsmapTest(BitcoinTestFramework):
+    def set_test_params(self):
+        self.setup_clean_chain = False
+        self.num_nodes = 1
+
+    def test_without_asmap_arg(self):
+        self.log.info('Test bitcoind with no -asmap arg passed')
+        self.stop_node(0)
+        with self.node.assert_debug_log(['Using /16 prefix for IP bucketing']):
+            self.start_node(0)
+
+    def test_asmap_with_relative_path(self):
+        self.log.info('Test bitcoind -asmap=<relative path>')
+        self.stop_node(0)
+        name = 'ASN_map'
+        filename = os.path.join(self.datadir, name)
+        shutil.copyfile(self.asmap_raw, filename)
+        with self.node.assert_debug_log(expected_messages(filename)):
+            self.start_node(0, ['-asmap={}'.format(name)])
+        os.remove(filename)
+
+    def test_default_asmap(self):
+        shutil.copyfile(self.asmap_raw, self.default_asmap)
+        for arg in ['-asmap', '-asmap=']:
+            self.log.info('Test bitcoind {} (using default map file)'.format(arg))
+            self.stop_node(0)
+            with self.node.assert_debug_log(expected_messages(self.default_asmap)):
+                self.start_node(0, [arg])
+        os.remove(self.default_asmap)
+
+    def test_default_asmap_with_missing_file(self):
+        self.log.info('Test bitcoind -asmap with missing default map file')
+        self.stop_node(0)
+        msg = "Error: Could not find or parse specified asmap: '\"{}\"'".format(self.default_asmap)
+        self.node.assert_start_raises_init_error(extra_args=['-asmap'], expected_msg=msg)
+
+    def run_test(self):
+        self.node = self.nodes[0]
+        self.datadir = os.path.join(self.node.datadir, self.chain)
+        self.default_asmap = os.path.join(self.datadir, DEFAULT_ASMAP_FILENAME)
+        self.asmap_raw = os.path.join(os.path.dirname(os.path.realpath(__file__)), ASMAP)
+
+        self.test_without_asmap_arg()
+        self.test_asmap_with_relative_path()
+        self.test_default_asmap()
+        self.test_default_asmap_with_missing_file()
+
+
+if __name__ == '__main__':
+    AsmapTest().main()

test/functional/test_runner.py

@@ -101,6 +101,7 @@ BASE_SCRIPTS = [
     'rpc_txoutproof.py',
     'wallet_listreceivedby.py',
     'wallet_abandonconflict.py',
+    'feature_asmap.py',
     'feature_csv_activation.py',
     'rpc_rawtransaction.py',
     'wallet_address_types.py',