[RPC] Add an uptime command that displays the amount of time that bitcoind has been running

test/functional/uptime.py

@@ -0,0 +1,32 @@
+#!/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 RPC call related to the uptime command.
+
+Test corresponds to code in rpc/server.cpp.
+"""
+
+import time
+
+from test_framework.test_framework import BitcoinTestFramework
+
+
+class UptimeTest(BitcoinTestFramework):
+    def __init__(self):
+        super().__init__()
+
+        self.num_nodes = 1
+        self.setup_clean_chain = True
+
+    def run_test(self):
+        self._test_uptime()
+
+    def _test_uptime(self):
+        wait_time = 10
+        self.nodes[0].setmocktime(int(time.time() + wait_time))
+        assert(self.nodes[0].uptime() >= wait_time)
+
+
+if __name__ == '__main__':
+    UptimeTest().main()