update to py3 conventions, update cmp to be py3 compatible, update map to return list for py3

qa/rpc-tests/zkey_import_export.py

@@ -1,15 +1,13 @@
-#!/usr/bin/env python
+#!/usr/bin/env python3
 # Copyright (c) 2017 The Zcash developers
 # Distributed under the MIT software license, see the accompanying
 # file COPYING or https://www.opensource.org/licenses/mit-license.php .
 
-import sys; assert sys.version_info < (3,), ur"This script does not run under Python 3. Please use Python 2.7.x."
-
 from decimal import Decimal
 from test_framework.test_framework import BitcoinTestFramework
 from test_framework.util import assert_equal, assert_greater_than, start_nodes,\
-    initialize_chain_clean, connect_nodes_bi, wait_and_assert_operationid_status
-
+    initialize_chain_clean, connect_nodes_bi, wait_and_assert_operationid_status, wait_and_assert_operationid_status_result
+from functools import reduce
 import logging
 
 logging.basicConfig(format='%(levelname)s:%(message)s', level=logging.INFO)
@@ -48,11 +46,7 @@ class ZkeyImportExportTest (BitcoinTestFramework):
         def verify_utxos(node, amts, zaddr):
             amts.sort(reverse=True)
             txs = node.z_listreceivedbyaddress(zaddr)
-
-            def cmp_confirmations_high_to_low(a, b):
-                return cmp(b["amount"], a["amount"])
-
-            txs.sort(cmp_confirmations_high_to_low)
+            txs.sort(key=lambda x: x["amount"], reverse=True)
             print("Sorted txs", txs)
             print("amts", amts)
 
@@ -94,11 +88,11 @@ class ZkeyImportExportTest (BitcoinTestFramework):
         # verify_utxos(charlie, [])
 
         # the amounts of each txn embodied which generates a single UTXO:
-        amounts = map(Decimal, ['2.3', '3.7', '0.1', '0.5', '1.0', '0.19'])
+        amounts = list(map(Decimal, ['2.3', '3.7', '0.1', '0.5', '1.0', '0.19']))
 
         # Internal test consistency assertion:
         assert_greater_than(
-            get_private_balance(alice),
+            Decimal(get_private_balance(alice)),
             reduce(Decimal.__add__, amounts))
 
         logging.info("Sending pre-export txns...")
@@ -141,7 +135,7 @@ class ZkeyImportExportTest (BitcoinTestFramework):
         verify_utxos(charlie, amounts, ipk_zaddr2["address"])
 
         # keep track of the fees incurred by bob (his sends)
-        bob_fee = Decimal(0)
+        bob_fee = Decimal("0")
 
         # Try to reproduce zombie balance reported in #1936
         # At generated zaddr, receive ZEC, and send ZEC back out. bob -> alice