[qa] Use python2/3 syntax

21 files changed, 78 insertions, 75 deletions

diff --git a/qa/pull-tester/rpc-tests.py b/qa/pull-tester/rpc-tests.py
index d794dbe806..6d3bda10ee 100755
--- a/qa/pull-tester/rpc-tests.py
+++ b/qa/pull-tester/rpc-tests.py
@@ -32,13 +32,13 @@ import re
 from tests_config import *
 
 #If imported values are not defined then set to zero (or disabled)
-if not vars().has_key('ENABLE_WALLET'):
+if 'ENABLE_WALLET' not in vars():
     ENABLE_WALLET=0
-if not vars().has_key('ENABLE_BITCOIND'):
+if 'ENABLE_BITCOIND' not in vars():
     ENABLE_BITCOIND=0
-if not vars().has_key('ENABLE_UTILS'):
+if 'ENABLE_UTILS' not in vars():
     ENABLE_UTILS=0
-if not vars().has_key('ENABLE_ZMQ'):
+if 'ENABLE_ZMQ' not in vars():
     ENABLE_ZMQ=0
     
 # python-zmq may not be installed. Handle this gracefully and with some helpful info
diff --git a/qa/rpc-tests/bip65-cltv-p2p.py b/qa/rpc-tests/bip65-cltv-p2p.py
index bbd518cf5f..316c5fe090 100755
--- a/qa/rpc-tests/bip65-cltv-p2p.py
+++ b/qa/rpc-tests/bip65-cltv-p2p.py
@@ -11,7 +11,7 @@ from test_framework.blocktools import create_coinbase, create_block
 from test_framework.comptool import TestInstance, TestManager
 from test_framework.script import CScript, OP_1NEGATE, OP_CHECKLOCKTIMEVERIFY, OP_DROP
 from binascii import unhexlify
-import cStringIO
+from io import BytesIO
 import time
 
 def cltv_invalidate(tx):
@@ -60,7 +60,7 @@ class BIP65Test(ComparisonTestFramework):
         rawtx = node.createrawtransaction(inputs, outputs)
         signresult = node.signrawtransaction(rawtx)
         tx = CTransaction()
-        f = cStringIO.StringIO(unhexlify(signresult['hex']))
+        f = BytesIO(unhexlify(signresult['hex']))
         tx.deserialize(f)
         return tx
 
diff --git a/qa/rpc-tests/bip68-112-113-p2p.py b/qa/rpc-tests/bip68-112-113-p2p.py
index 7d3c59be3e..f391cb0b7a 100755
--- a/qa/rpc-tests/bip68-112-113-p2p.py
+++ b/qa/rpc-tests/bip68-112-113-p2p.py
@@ -11,7 +11,7 @@ from test_framework.blocktools import create_coinbase, create_block
 from test_framework.comptool import TestInstance, TestManager
 from test_framework.script import *
 from binascii import unhexlify
-import cStringIO
+from io import BytesIO
 import time
 
 '''
@@ -119,7 +119,7 @@ class BIP68_112_113Test(ComparisonTestFramework):
         outputs = { to_address : amount }
         rawtx = node.createrawtransaction(inputs, outputs)
         tx = CTransaction()
-        f = cStringIO.StringIO(unhexlify(rawtx))
+        f = BytesIO(unhexlify(rawtx))
         tx.deserialize(f)
         return tx
 
@@ -127,7 +127,7 @@ class BIP68_112_113Test(ComparisonTestFramework):
         rawtx = ToHex(unsignedtx)
         signresult = node.signrawtransaction(rawtx)
         tx = CTransaction()
-        f = cStringIO.StringIO(unhexlify(signresult['hex']))
+        f = BytesIO(unhexlify(signresult['hex']))
         tx.deserialize(f)
         return tx
 
diff --git a/qa/rpc-tests/bip9-softforks.py b/qa/rpc-tests/bip9-softforks.py
index cbb1b7d4ce..445c044944 100755
--- a/qa/rpc-tests/bip9-softforks.py
+++ b/qa/rpc-tests/bip9-softforks.py
@@ -11,7 +11,7 @@ from test_framework.blocktools import create_coinbase, create_block
 from test_framework.comptool import TestInstance, TestManager
 from test_framework.script import CScript, OP_1NEGATE, OP_NOP3, OP_DROP
 from binascii import hexlify, unhexlify
-import cStringIO
+from io import BytesIO
 import time
 import itertools
 
@@ -53,7 +53,7 @@ class BIP9SoftForksTest(ComparisonTestFramework):
         outputs = { to_address : amount }
         rawtx = node.createrawtransaction(inputs, outputs)
         tx = CTransaction()
-        f = cStringIO.StringIO(unhexlify(rawtx))
+        f = BytesIO(unhexlify(rawtx))
         tx.deserialize(f)
         tx.nVersion = 2
         return tx
@@ -61,7 +61,7 @@ class BIP9SoftForksTest(ComparisonTestFramework):
     def sign_transaction(self, node, tx):
         signresult = node.signrawtransaction(hexlify(tx.serialize()))
         tx = CTransaction()
-        f = cStringIO.StringIO(unhexlify(signresult['hex']))
+        f = BytesIO(unhexlify(signresult['hex']))
         tx.deserialize(f)
         return tx
 
@@ -217,4 +217,4 @@ class BIP9SoftForksTest(ComparisonTestFramework):
         tx.nLockTime = self.last_block_time
 
 if __name__ == '__main__':
-    BIP9SoftForksTest().main()
\ No newline at end of file
+    BIP9SoftForksTest().main()
diff --git a/qa/rpc-tests/bipdersig-p2p.py b/qa/rpc-tests/bipdersig-p2p.py
index 544e4a9670..f0d81a6f44 100755
--- a/qa/rpc-tests/bipdersig-p2p.py
+++ b/qa/rpc-tests/bipdersig-p2p.py
@@ -11,7 +11,7 @@ from test_framework.blocktools import create_coinbase, create_block
 from test_framework.comptool import TestInstance, TestManager
 from test_framework.script import CScript
 from binascii import unhexlify
-import cStringIO
+from io import BytesIO
 import time
 
 # A canonical signature consists of: 
@@ -68,7 +68,7 @@ class BIP66Test(ComparisonTestFramework):
         rawtx = node.createrawtransaction(inputs, outputs)
         signresult = node.signrawtransaction(rawtx)
         tx = CTransaction()
-        f = cStringIO.StringIO(unhexlify(signresult['hex']))
+        f = BytesIO(unhexlify(signresult['hex']))
         tx.deserialize(f)
         return tx
 
diff --git a/qa/rpc-tests/decodescript.py b/qa/rpc-tests/decodescript.py
index 490808d49d..2dfafac2fc 100755
--- a/qa/rpc-tests/decodescript.py
+++ b/qa/rpc-tests/decodescript.py
@@ -7,7 +7,7 @@ from test_framework.test_framework import BitcoinTestFramework
 from test_framework.util import *
 from test_framework.mininode import *
 from binascii import hexlify, unhexlify
-from cStringIO import StringIO
+from io import BytesIO
 
 class DecodeScriptTest(BitcoinTestFramework):
     """Tests decoding scripts via RPC command "decodescript"."""
@@ -131,7 +131,7 @@ class DecodeScriptTest(BitcoinTestFramework):
         assert_equal('OP_DUP OP_HASH160 dc863734a218bfe83ef770ee9d41a27f824a6e56 OP_EQUALVERIFY OP_CHECKSIG', rpc_result['vout'][0]['scriptPubKey']['asm'])
         assert_equal('OP_HASH160 2a5edea39971049a540474c6a99edf0aa4074c58 OP_EQUAL', rpc_result['vout'][1]['scriptPubKey']['asm'])
         txSave = CTransaction()
-        txSave.deserialize(StringIO(unhexlify(tx)))
+        txSave.deserialize(BytesIO(unhexlify(tx)))
 
         # make sure that a specifically crafted op_return value will not pass all the IsDERSignature checks and then get decoded as a sighash type
         tx = '01000000015ded05872fdbda629c7d3d02b194763ce3b9b1535ea884e3c8e765d42e316724020000006b48304502204c10d4064885c42638cbff3585915b322de33762598321145ba033fc796971e2022100bb153ad3baa8b757e30a2175bd32852d2e1cb9080f84d7e32fcdfd667934ef1b012103163c0ff73511ea1743fb5b98384a2ff09dd06949488028fd819f4d83f56264efffffffff0200000000000000000b6a0930060201000201000180380100000000001976a9141cabd296e753837c086da7a45a6c2fe0d49d7b7b88ac00000000'
diff --git a/qa/rpc-tests/disablewallet.py b/qa/rpc-tests/disablewallet.py
index 5af8158467..cb868029fa 100755
--- a/qa/rpc-tests/disablewallet.py
+++ b/qa/rpc-tests/disablewallet.py
@@ -32,7 +32,7 @@ class DisableWalletTest (BitcoinTestFramework):
         # Checking mining to an address without a wallet
         try:
             self.nodes[0].generatetoaddress(1, 'mneYUmWYsuk7kySiURxCi3AGxrAqZxLgPZ')
-        except JSONRPCException,e:
+        except JSONRPCException as e:
             assert("Invalid address" not in e.error['message'])
             assert("ProcessNewBlock, block not accepted" not in e.error['message'])
             assert("Couldn't create new block" not in e.error['message'])
@@ -40,7 +40,7 @@ class DisableWalletTest (BitcoinTestFramework):
         try:
             self.nodes[0].generatetoaddress(1, '3J98t1WpEZ73CNmQviecrnyiWrnqRhWNLy')
             raise AssertionError("Must not mine to invalid address!")
-        except JSONRPCException,e:
+        except JSONRPCException as e:
             assert("Invalid address" in e.error['message'])
 
 if __name__ == '__main__':
diff --git a/qa/rpc-tests/fundrawtransaction.py b/qa/rpc-tests/fundrawtransaction.py
index 4458712815..82f2f4f5c5 100755
--- a/qa/rpc-tests/fundrawtransaction.py
+++ b/qa/rpc-tests/fundrawtransaction.py
@@ -209,7 +209,7 @@ class RawTransactionsTest(BitcoinTestFramework):
         matchingOuts = 0
         for i, out in enumerate(dec_tx['vout']):
             totalOut += out['value']
-            if outputs.has_key(out['scriptPubKey']['addresses'][0]):
+            if out['scriptPubKey']['addresses'][0] in outputs:
                 matchingOuts+=1
             else:
                 assert_equal(i, rawtxfund['changepos'])
@@ -249,7 +249,7 @@ class RawTransactionsTest(BitcoinTestFramework):
         matchingOuts = 0
         for out in dec_tx['vout']:
             totalOut += out['value']
-            if outputs.has_key(out['scriptPubKey']['addresses'][0]):
+            if out['scriptPubKey']['addresses'][0] in outputs:
                 matchingOuts+=1
 
         assert_equal(matchingOuts, 1)
@@ -291,7 +291,7 @@ class RawTransactionsTest(BitcoinTestFramework):
         matchingOuts = 0
         for out in dec_tx['vout']:
             totalOut += out['value']
-            if outputs.has_key(out['scriptPubKey']['addresses'][0]):
+            if out['scriptPubKey']['addresses'][0] in outputs:
                 matchingOuts+=1
 
         assert_equal(matchingOuts, 2)
@@ -309,7 +309,7 @@ class RawTransactionsTest(BitcoinTestFramework):
         try:
             rawtxfund = self.nodes[2].fundrawtransaction(rawtx)
             raise AssertionError("Spent more than available")
-        except JSONRPCException,e:
+        except JSONRPCException as e:
             assert("Insufficient" in e.error['message'])
 
 
diff --git a/qa/rpc-tests/importprunedfunds.py b/qa/rpc-tests/importprunedfunds.py
index 5cbdcde9aa..db875800d4 100755
--- a/qa/rpc-tests/importprunedfunds.py
+++ b/qa/rpc-tests/importprunedfunds.py
@@ -82,7 +82,7 @@ class ImportPrunedFundsTest(BitcoinTestFramework):
         #Import with no affiliated address
         try:
             result1 = self.nodes[1].importprunedfunds(rawtxn1, proof1, "")
-        except JSONRPCException,e:
+        except JSONRPCException as e:
             errorString = e.error['message']
 
         assert('No addresses' in errorString)
@@ -119,7 +119,7 @@ class ImportPrunedFundsTest(BitcoinTestFramework):
 
         try:
             self.nodes[1].removeprunedfunds(txnid1)
-        except JSONRPCException,e:
+        except JSONRPCException as e:
             errorString = e.error['message']
 
         assert('does not exist' in errorString)
diff --git a/qa/rpc-tests/keypool.py b/qa/rpc-tests/keypool.py
index 95d0d6832a..5253d49c30 100755
--- a/qa/rpc-tests/keypool.py
+++ b/qa/rpc-tests/keypool.py
@@ -46,7 +46,7 @@ class KeyPoolTest(BitcoinTestFramework):
         try:
             addr = nodes[0].getnewaddress()
             raise AssertionError('Keypool should be exhausted after one address')
-        except JSONRPCException,e:
+        except JSONRPCException as e:
             assert(e.error['code']==-12)
 
         # put three new keys in the keypool
@@ -66,7 +66,7 @@ class KeyPoolTest(BitcoinTestFramework):
         try:
             addr = nodes[0].getrawchangeaddress()
             raise AssertionError('Keypool should be exhausted after three addresses')
-        except JSONRPCException,e:
+        except JSONRPCException as e:
             assert(e.error['code']==-12)
 
         # refill keypool with three new addresses
@@ -84,7 +84,7 @@ class KeyPoolTest(BitcoinTestFramework):
         try:
             nodes[0].generate(1)
             raise AssertionError('Keypool should be exhausted after three addesses')
-        except JSONRPCException,e:
+        except JSONRPCException as e:
             assert(e.error['code']==-12)
 
     def setup_chain(self):
diff --git a/qa/rpc-tests/listtransactions.py b/qa/rpc-tests/listtransactions.py
index da1e98dc33..c4eca519b7 100755
--- a/qa/rpc-tests/listtransactions.py
+++ b/qa/rpc-tests/listtransactions.py
@@ -8,12 +8,12 @@
 from test_framework.test_framework import BitcoinTestFramework
 from test_framework.util import *
 from test_framework.mininode import CTransaction, COIN
-import cStringIO
+from io import BytesIO
 import binascii
 
 def txFromHex(hexstring):
     tx = CTransaction()
-    f = cStringIO.StringIO(binascii.unhexlify(hexstring))
+    f = BytesIO(binascii.unhexlify(hexstring))
     tx.deserialize(f)
     return tx
 
diff --git a/qa/rpc-tests/rawtransactions.py b/qa/rpc-tests/rawtransactions.py
index dd9e5e28a5..9f660c8bda 100755
--- a/qa/rpc-tests/rawtransactions.py
+++ b/qa/rpc-tests/rawtransactions.py
@@ -59,7 +59,7 @@ class RawTransactionsTest(BitcoinTestFramework):
         errorString = ""
         try:
             rawtx   = self.nodes[2].sendrawtransaction(rawtx['hex'])
-        except JSONRPCException,e:
+        except JSONRPCException as e:
             errorString = e.error['message']
 
         assert("Missing inputs" in errorString)
diff --git a/qa/rpc-tests/rest.py b/qa/rpc-tests/rest.py
index 8c83536501..3c8a405bdd 100755
--- a/qa/rpc-tests/rest.py
+++ b/qa/rpc-tests/rest.py
@@ -11,8 +11,9 @@
 from test_framework.test_framework import BitcoinTestFramework
 from test_framework.util import *
 from struct import *
+from io import BytesIO
+from codecs import encode
 import binascii
-import StringIO
 
 try:
     import http.client as httplib
@@ -146,7 +147,7 @@ class RESTTest (BitcoinTestFramework):
         binaryRequest += pack("i", 0)
 
         bin_response = http_post_call(url.hostname, url.port, '/rest/getutxos'+self.FORMAT_SEPARATOR+'bin', binaryRequest)
-        output = StringIO.StringIO()
+        output = BytesIO()
         output.write(bin_response)
         output.seek(0)
         chainHeight = unpack("i", output.read(4))[0]
@@ -233,7 +234,7 @@ class RESTTest (BitcoinTestFramework):
         assert_equal(response_hex.status, 200)
         assert_greater_than(int(response_hex.getheader('content-length')), 160)
         response_hex_str = response_hex.read()
-        assert_equal(response_str.encode("hex")[0:160], response_hex_str[0:160])
+        assert_equal(encode(response_str, "hex")[0:160], response_hex_str[0:160])
 
         # compare with hex block header
         response_header_hex = http_get_call(url.hostname, url.port, '/rest/headers/1/'+bb_hash+self.FORMAT_SEPARATOR+"hex", True)
@@ -241,7 +242,7 @@ class RESTTest (BitcoinTestFramework):
         assert_greater_than(int(response_header_hex.getheader('content-length')), 160)
         response_header_hex_str = response_header_hex.read()
         assert_equal(response_hex_str[0:160], response_header_hex_str[0:160])
-        assert_equal(response_header_str.encode("hex")[0:160], response_header_hex_str[0:160])
+        assert_equal(encode(response_header_str, "hex")[0:160], response_header_hex_str[0:160])
 
         # check json format
         block_json_string = http_get_call(url.hostname, url.port, '/rest/block/'+bb_hash+self.FORMAT_SEPARATOR+'json')
diff --git a/qa/rpc-tests/smartfees.py b/qa/rpc-tests/smartfees.py
index b209ae0c16..6274cd0530 100755
--- a/qa/rpc-tests/smartfees.py
+++ b/qa/rpc-tests/smartfees.py
@@ -105,7 +105,7 @@ def check_estimates(node, fees_seen, max_invalid, print_estimates = True):
         print([str(all_estimates[e-1]) for e in [1,2,3,6,15,25]])
     delta = 1.0e-6 # account for rounding error
     last_e = max(fees_seen)
-    for e in filter(lambda x: x >= 0, all_estimates):
+    for e in [x for x in all_estimates if x >= 0]:
         # Estimates should be within the bounds of what transactions fees actually were:
         if float(e)+delta < min(fees_seen) or float(e)-delta > max(fees_seen):
             raise AssertionError("Estimated fee (%f) out of range (%f,%f)"
diff --git a/qa/rpc-tests/test_framework/blockstore.py b/qa/rpc-tests/test_framework/blockstore.py
index b9775b477c..73d9ffbb2f 100644
--- a/qa/rpc-tests/test_framework/blockstore.py
+++ b/qa/rpc-tests/test_framework/blockstore.py
@@ -3,8 +3,9 @@
 #             and for constructing a getheaders message
 #
 
-from mininode import *
+from .mininode import *
 import dbm
+from io import BytesIO
 
 class BlockStore(object):
     def __init__(self, datadir):
@@ -21,7 +22,7 @@ class BlockStore(object):
             serialized_block = self.blockDB[repr(blockhash)]
         except KeyError:
             return None
-        f = cStringIO.StringIO(serialized_block)
+        f = BytesIO(serialized_block)
         ret = CBlock()
         ret.deserialize(f)
         ret.calc_sha256()
@@ -115,7 +116,7 @@ class TxStore(object):
             serialized_tx = self.txDB[repr(txhash)]
         except KeyError:
             return None
-        f = cStringIO.StringIO(serialized_tx)
+        f = BytesIO(serialized_tx)
         ret = CTransaction()
         ret.deserialize(f)
         ret.calc_sha256()
diff --git a/qa/rpc-tests/test_framework/blocktools.py b/qa/rpc-tests/test_framework/blocktools.py
index b075f69c47..425e6dcdde 100644
--- a/qa/rpc-tests/test_framework/blocktools.py
+++ b/qa/rpc-tests/test_framework/blocktools.py
@@ -4,8 +4,8 @@
 # file COPYING or http://www.opensource.org/licenses/mit-license.php.
 #
 
-from mininode import *
-from script import CScript, OP_TRUE, OP_CHECKSIG
+from .mininode import *
+from .script import CScript, OP_TRUE, OP_CHECKSIG
 
 # Create a block (with regtest difficulty)
 def create_block(hashprev, coinbase, nTime=None):
diff --git a/qa/rpc-tests/test_framework/comptool.py b/qa/rpc-tests/test_framework/comptool.py
index f19edbf069..6279070fbc 100755
--- a/qa/rpc-tests/test_framework/comptool.py
+++ b/qa/rpc-tests/test_framework/comptool.py
@@ -4,9 +4,9 @@
 # file COPYING or http://www.opensource.org/licenses/mit-license.php.
 #
 
-from mininode import *
-from blockstore import BlockStore, TxStore
-from util import p2p_port
+from .mininode import *
+from .blockstore import BlockStore, TxStore
+from .util import p2p_port
 
 '''
 This is a tool for comparing two or more bitcoinds to each other
diff --git a/qa/rpc-tests/test_framework/mininode.py b/qa/rpc-tests/test_framework/mininode.py
index 20386c642c..07d1827dfe 100755
--- a/qa/rpc-tests/test_framework/mininode.py
+++ b/qa/rpc-tests/test_framework/mininode.py
@@ -24,7 +24,8 @@ import binascii
 import time
 import sys
 import random
-import cStringIO
+from io import BytesIO
+from codecs import encode
 import hashlib
 from threading import RLock
 from threading import Thread
@@ -75,12 +76,12 @@ def deser_string(f):
 
 def ser_string(s):
     if len(s) < 253:
-        return chr(len(s)) + s
+        return struct.pack("B", len(s)) + s
     elif len(s) < 0x10000:
-        return chr(253) + struct.pack("<H", len(s)) + s
+        return struct.pack("B", 253) + struct.pack("<H", len(s)) + s
     elif len(s) < 0x100000000L:
-        return chr(254) + struct.pack("<I", len(s)) + s
-    return chr(255) + struct.pack("<Q", len(s)) + s
+        return struct.pack("B", 254) + struct.pack("<I", len(s)) + s
+    return struct.pack("B", 255) + struct.pack("<Q", len(s)) + s
 
 
 def deser_uint256(f):
@@ -132,13 +133,13 @@ def deser_vector(f, c):
 def ser_vector(l):
     r = ""
     if len(l) < 253:
-        r = chr(len(l))
+        r = struct.pack("B", len(l))
     elif len(l) < 0x10000:
-        r = chr(253) + struct.pack("<H", len(l))
+        r = struct.pack("B", 253) + struct.pack("<H", len(l))
     elif len(l) < 0x100000000L:
-        r = chr(254) + struct.pack("<I", len(l))
+        r = struct.pack("B", 254) + struct.pack("<I", len(l))
     else:
-        r = chr(255) + struct.pack("<Q", len(l))
+        r = struct.pack("B", 255) + struct.pack("<Q", len(l))
     for i in l:
         r += i.serialize()
     return r
@@ -162,13 +163,13 @@ def deser_uint256_vector(f):
 def ser_uint256_vector(l):
     r = ""
     if len(l) < 253:
-        r = chr(len(l))
+        r = struct.pack("B", len(l))
     elif len(l) < 0x10000:
-        r = chr(253) + struct.pack("<H", len(l))
+        r = struct.pack("B", 253) + struct.pack("<H", len(l))
     elif len(l) < 0x100000000L:
-        r = chr(254) + struct.pack("<I", len(l))
+        r = struct.pack("B", 254) + struct.pack("<I", len(l))
     else:
-        r = chr(255) + struct.pack("<Q", len(l))
+        r = struct.pack("B", 255) + struct.pack("<Q", len(l))
     for i in l:
         r += ser_uint256(i)
     return r
@@ -192,13 +193,13 @@ def deser_string_vector(f):
 def ser_string_vector(l):
     r = ""
     if len(l) < 253:
-        r = chr(len(l))
+        r = struct.pack("B", len(l))
     elif len(l) < 0x10000:
-        r = chr(253) + struct.pack("<H", len(l))
+        r = struct.pack("B", 253) + struct.pack("<H", len(l))
     elif len(l) < 0x100000000L:
-        r = chr(254) + struct.pack("<I", len(l))
+        r = struct.pack("B", 254) + struct.pack("<I", len(l))
     else:
-        r = chr(255) + struct.pack("<Q", len(l))
+        r = struct.pack("B", 255) + struct.pack("<Q", len(l))
     for sv in l:
         r += ser_string(sv)
     return r
@@ -222,20 +223,20 @@ def deser_int_vector(f):
 def ser_int_vector(l):
     r = ""
     if len(l) < 253:
-        r = chr(len(l))
+        r = struct.pack("B", len(l))
     elif len(l) < 0x10000:
-        r = chr(253) + struct.pack("<H", len(l))
+        r = struct.pack("B", 253) + struct.pack("<H", len(l))
     elif len(l) < 0x100000000L:
-        r = chr(254) + struct.pack("<I", len(l))
+        r = struct.pack("B", 254) + struct.pack("<I", len(l))
     else:
-        r = chr(255) + struct.pack("<Q", len(l))
+        r = struct.pack("B", 255) + struct.pack("<Q", len(l))
     for i in l:
         r += struct.pack("<i", i)
     return r
 
 # Deserialize from a hex string representation (eg from RPC)
 def FromHex(obj, hex_string):
-    obj.deserialize(cStringIO.StringIO(binascii.unhexlify(hex_string)))
+    obj.deserialize(BytesIO(binascii.unhexlify(hex_string)))
     return obj
 
 # Convert a binary-serializable object to hex (eg for submission via RPC)
@@ -423,7 +424,7 @@ class CTransaction(object):
     def calc_sha256(self):
         if self.sha256 is None:
             self.sha256 = uint256_from_str(hash256(self.serialize()))
-        self.hash = hash256(self.serialize())[::-1].encode('hex_codec')
+        self.hash = encode(hash256(self.serialize())[::-1], 'hex')
 
     def is_valid(self):
         self.calc_sha256()
@@ -492,7 +493,7 @@ class CBlockHeader(object):
             r += struct.pack("<I", self.nBits)
             r += struct.pack("<I", self.nNonce)
             self.sha256 = uint256_from_str(hash256(r))
-            self.hash = hash256(r)[::-1].encode('hex_codec')
+            self.hash = encode(hash256(r)[::-1], 'hex')
 
     def rehash(self):
         self.sha256 = None
@@ -1281,7 +1282,7 @@ class NodeConn(asyncore.dispatcher):
                     raise ValueError("got bad checksum " + repr(self.recvbuf))
                 self.recvbuf = self.recvbuf[4+12+4+4+msglen:]
             if command in self.messagemap:
-                f = cStringIO.StringIO(msg)
+                f = BytesIO(msg)
                 t = self.messagemap[command]()
                 t.deserialize(f)
                 self.got_message(t)
diff --git a/qa/rpc-tests/test_framework/socks5.py b/qa/rpc-tests/test_framework/socks5.py
index 1dbfb98d5d..12327a6c5f 100644
--- a/qa/rpc-tests/test_framework/socks5.py
+++ b/qa/rpc-tests/test_framework/socks5.py
@@ -117,7 +117,7 @@ class Socks5Connection(object):
             self.serv.queue.put(cmdin)
             print('Proxy: ', cmdin)
             # Fall through to disconnect
-        except Exception,e:
+        except Exception as e:
             traceback.print_exc(file=sys.stderr)
             self.serv.queue.put(e)
         finally:
diff --git a/qa/rpc-tests/test_framework/test_framework.py b/qa/rpc-tests/test_framework/test_framework.py
index 584f318d0b..19ee472609 100755
--- a/qa/rpc-tests/test_framework/test_framework.py
+++ b/qa/rpc-tests/test_framework/test_framework.py
@@ -26,7 +26,7 @@ from .util import (
     check_json_precision,
     initialize_chain_clean,
 )
-from authproxy import AuthServiceProxy, JSONRPCException
+from .authproxy import AuthServiceProxy, JSONRPCException
 
 
 class BitcoinTestFramework(object):
@@ -140,7 +140,7 @@ class BitcoinTestFramework(object):
             print("JSONRPC error: "+e.error['message'])
             traceback.print_tb(sys.exc_info()[2])
         except AssertionError as e:
-            print("Assertion failed: "+e.message)
+            print("Assertion failed: "+ str(e))
             traceback.print_tb(sys.exc_info()[2])
         except Exception as e:
             print("Unexpected exception caught during testing: "+str(e))
diff --git a/qa/rpc-tests/wallet.py b/qa/rpc-tests/wallet.py
index e6ce397119..cb876aae5c 100755
--- a/qa/rpc-tests/wallet.py
+++ b/qa/rpc-tests/wallet.py
@@ -249,7 +249,7 @@ class WalletTest (BitcoinTestFramework):
         errorString = ""
         try:
             txId  = self.nodes[0].sendtoaddress(self.nodes[2].getnewaddress(), "1f-4")
-        except JSONRPCException,e:
+        except JSONRPCException as e:
             errorString = e.error['message']
 
         assert("Invalid amount" in errorString)
@@ -257,7 +257,7 @@ class WalletTest (BitcoinTestFramework):
         errorString = ""
         try:
             self.nodes[0].generate("2") #use a string to as block amount parameter must fail because it's not interpreted as amount
-        except JSONRPCException,e:
+        except JSONRPCException as e:
             errorString = e.error['message']
 
         assert("not an integer" in errorString)
@@ -271,7 +271,7 @@ class WalletTest (BitcoinTestFramework):
         # Check that the txid and balance is found by node1
         try:
             self.nodes[1].gettransaction(cbTxId)
-        except JSONRPCException,e:
+        except JSONRPCException as e:
             assert("Invalid or non-wallet transaction id" not in e.error['message'])
 
         #check if wallet or blochchain maintenance changes the balance