[tests] Add uacomment tests

Checks for setting the value, max length and reserved characters

test/functional/test_runner.py

@@ -124,6 +124,7 @@
     'resendwallettransactions.py',
     'minchainwork.py',
     'p2p-fingerprint.py',
+    'uacomment.py',
 ]
 
 EXTENDED_SCRIPTS = [

test/functional/uacomment.py

@@ -0,0 +1,35 @@
+#!/usr/bin/env python3
+# Copyright (c) 2017 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 -uacomment option."""
+
+from test_framework.test_framework import BitcoinTestFramework
+from test_framework.util import assert_equal
+
+class UacommentTest(BitcoinTestFramework):
+    def set_test_params(self):
+        self.num_nodes = 1
+        self.setup_clean_chain = True
+
+    def run_test(self):
+        self.log.info("test multiple -uacomment")
+        test_uacomment = self.nodes[0].getnetworkinfo()["subversion"][-12:-1]
+        assert_equal(test_uacomment, "(testnode0)")
+
+        self.restart_node(0, ["-uacomment=foo"])
+        foo_uacomment = self.nodes[0].getnetworkinfo()["subversion"][-17:-1]
+        assert_equal(foo_uacomment, "(testnode0; foo)")
+
+        self.log.info("test -uacomment max length")
+        self.stop_node(0)
+        expected = "Total length of network version string (286) exceeds maximum length (256). Reduce the number or size of uacomments."
+        self.assert_start_raises_init_error(0, ["-uacomment=" + 'a' * 256], expected)
+
+        self.log.info("test -uacomment unsafe characters")
+        for unsafe_char in ['/', ':', '(', ')']:
+            expected = "User Agent comment (" + unsafe_char + ") contains unsafe characters"
+            self.assert_start_raises_init_error(0, ["-uacomment=" + unsafe_char], expected)
+
+if __name__ == '__main__':
+    UacommentTest().main()