diff --git a/qa/pull-tester/rpc-tests.py b/qa/pull-tester/rpc-tests.py
index 37014cf76..2f287a926 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
 
 ENABLE_COVERAGE=0
diff --git a/qa/rpc-tests/bip65-cltv-p2p.py b/qa/rpc-tests/bip65-cltv-p2p.py
index 9b1fdd935..5cb78e7a4 100755
--- a/qa/rpc-tests/bip65-cltv-p2p.py
+++ b/qa/rpc-tests/bip65-cltv-p2p.py
@@ -10,8 +10,7 @@ from test_framework.mininode import CTransaction, NetworkThread
 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 +59,7 @@ class BIP65Test(ComparisonTestFramework):
         rawtx = node.createrawtransaction(inputs, outputs)
         signresult = node.signrawtransaction(rawtx)
         tx = CTransaction()
-        f = cStringIO.StringIO(unhexlify(signresult['hex']))
+        f = BytesIO(hex_str_to_bytes(signresult['hex']))
         tx.deserialize(f)
         return tx
 
@@ -70,7 +69,7 @@ class BIP65Test(ComparisonTestFramework):
         height = 3  # height of the next block to build
         self.tip = int ("0x" + self.nodes[0].getbestblockhash() + "L", 0)
         self.nodeaddress = self.nodes[0].getnewaddress()
-        self.last_block_time = time.time()
+        self.last_block_time = int(time.time())
 
         ''' 98 more version 3 blocks '''
         test_blocks = []
diff --git a/qa/rpc-tests/bip68-112-113-p2p.py b/qa/rpc-tests/bip68-112-113-p2p.py
index 10b90318c..3bcfdabe2 100755
--- a/qa/rpc-tests/bip68-112-113-p2p.py
+++ b/qa/rpc-tests/bip68-112-113-p2p.py
@@ -10,8 +10,7 @@ from test_framework.mininode import ToHex, CTransaction, NetworkThread
 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 +118,7 @@ class BIP68_112_113Test(ComparisonTestFramework):
         outputs = { to_address : amount }
         rawtx = node.createrawtransaction(inputs, outputs)
         tx = CTransaction()
-        f = cStringIO.StringIO(unhexlify(rawtx))
+        f = BytesIO(hex_str_to_bytes(rawtx))
         tx.deserialize(f)
         return tx
 
@@ -127,7 +126,7 @@ class BIP68_112_113Test(ComparisonTestFramework):
         rawtx = ToHex(unsignedtx)
         signresult = node.signrawtransaction(rawtx)
         tx = CTransaction()
-        f = cStringIO.StringIO(unhexlify(signresult['hex']))
+        f = BytesIO(hex_str_to_bytes(signresult['hex']))
         tx.deserialize(f)
         return tx
 
diff --git a/qa/rpc-tests/bip68-sequence.py b/qa/rpc-tests/bip68-sequence.py
index 4f4a39f15..33e05dfc5 100755
--- a/qa/rpc-tests/bip68-sequence.py
+++ b/qa/rpc-tests/bip68-sequence.py
@@ -13,7 +13,6 @@ from test_framework.script import *
 from test_framework.mininode import *
 from test_framework.blocktools import *
 
-COIN = 100000000
 SEQUENCE_LOCKTIME_DISABLE_FLAG = (1<<31)
 SEQUENCE_LOCKTIME_TYPE_FLAG = (1<<22) # this means use time (0 means height)
 SEQUENCE_LOCKTIME_GRANULARITY = 9 # this is a bit-shift
diff --git a/qa/rpc-tests/bip9-softforks.py b/qa/rpc-tests/bip9-softforks.py
index 97c6f3f3a..d131eed92 100755
--- a/qa/rpc-tests/bip9-softforks.py
+++ b/qa/rpc-tests/bip9-softforks.py
@@ -10,8 +10,7 @@ from test_framework.mininode import CTransaction, NetworkThread
 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
 
@@ -30,7 +29,6 @@ test that enforcement has triggered
 '''
 
 
-
 class BIP9SoftForksTest(ComparisonTestFramework):
 
     def __init__(self):
@@ -53,15 +51,15 @@ class BIP9SoftForksTest(ComparisonTestFramework):
         outputs = { to_address : amount }
         rawtx = node.createrawtransaction(inputs, outputs)
         tx = CTransaction()
-        f = cStringIO.StringIO(unhexlify(rawtx))
+        f = BytesIO(hex_str_to_bytes(rawtx))
         tx.deserialize(f)
         tx.nVersion = 2
         return tx
 
     def sign_transaction(self, node, tx):
-        signresult = node.signrawtransaction(hexlify(tx.serialize()))
+        signresult = node.signrawtransaction(bytes_to_hex_str(tx.serialize()))
         tx = CTransaction()
-        f = cStringIO.StringIO(unhexlify(signresult['hex']))
+        f = BytesIO(hex_str_to_bytes(signresult['hex']))
         tx.deserialize(f)
         return tx
 
@@ -184,7 +182,6 @@ class BIP9SoftForksTest(ComparisonTestFramework):
         NetworkThread().start() # Start up network handling in another thread
 
 
-
     def get_tests(self):
         for test in itertools.chain(
                 self.test_BIP('csv', 536870913, self.sequence_lock_invalidate, self.donothing),
@@ -217,4 +214,4 @@ 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 9118b8fac..b1db5ba4a 100755
--- a/qa/rpc-tests/bipdersig-p2p.py
+++ b/qa/rpc-tests/bipdersig-p2p.py
@@ -10,8 +10,7 @@ from test_framework.mininode import CTransaction, NetworkThread
 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: 
@@ -25,7 +24,7 @@ def unDERify(tx):
     newscript = []
     for i in scriptSig:
         if (len(newscript) == 0):
-            newscript.append(i[0:-1] + '\0' + i[-1])
+            newscript.append(i[0:-1] + b'\0' + i[-1:])
         else:
             newscript.append(i)
     tx.vin[0].scriptSig = CScript(newscript)
@@ -68,7 +67,7 @@ class BIP66Test(ComparisonTestFramework):
         rawtx = node.createrawtransaction(inputs, outputs)
         signresult = node.signrawtransaction(rawtx)
         tx = CTransaction()
-        f = cStringIO.StringIO(unhexlify(signresult['hex']))
+        f = BytesIO(hex_str_to_bytes(signresult['hex']))
         tx.deserialize(f)
         return tx
 
@@ -78,7 +77,7 @@ class BIP66Test(ComparisonTestFramework):
         height = 3  # height of the next block to build
         self.tip = int ("0x" + self.nodes[0].getbestblockhash() + "L", 0)
         self.nodeaddress = self.nodes[0].getnewaddress()
-        self.last_block_time = time.time()
+        self.last_block_time = int(time.time())
 
         ''' 98 more version 2 blocks '''
         test_blocks = []
diff --git a/qa/rpc-tests/blockchain.py b/qa/rpc-tests/blockchain.py
index b0fc7b017..d2b5f4129 100755
--- a/qa/rpc-tests/blockchain.py
+++ b/qa/rpc-tests/blockchain.py
@@ -28,6 +28,7 @@ class BlockchainTest(BitcoinTestFramework):
     Test blockchain-related RPC calls:
 
         - gettxoutsetinfo
+        - verifychain
 
     """
 
@@ -44,6 +45,7 @@ class BlockchainTest(BitcoinTestFramework):
     def run_test(self):
         self._test_gettxoutsetinfo()
         self._test_getblockheader()
+        self.nodes[0].verifychain(4, 0)
 
     def _test_gettxoutsetinfo(self):
         node = self.nodes[0]
diff --git a/qa/rpc-tests/decodescript.py b/qa/rpc-tests/decodescript.py
index 490808d49..578844f2c 100755
--- a/qa/rpc-tests/decodescript.py
+++ b/qa/rpc-tests/decodescript.py
@@ -6,8 +6,7 @@
 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 +130,7 @@ 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(hex_str_to_bytes(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'
@@ -147,7 +146,7 @@ class DecodeScriptTest(BitcoinTestFramework):
         # some more full transaction tests of varying specific scriptSigs. used instead of
         # tests in decodescript_script_sig because the decodescript RPC is specifically
         # for working on scriptPubKeys (argh!).
-        push_signature = hexlify(txSave.vin[0].scriptSig)[2:(0x48*2+4)]
+        push_signature = bytes_to_hex_str(txSave.vin[0].scriptSig)[2:(0x48*2+4)]
         signature = push_signature[2:]
         der_signature = signature[:-2]
         signature_sighash_decoded = der_signature + '[ALL]'
@@ -156,25 +155,24 @@ class DecodeScriptTest(BitcoinTestFramework):
         signature_2_sighash_decoded = der_signature + '[NONE|ANYONECANPAY]'
 
         # 1) P2PK scriptSig
-        txSave.vin[0].scriptSig = unhexlify(push_signature)
-        rpc_result = self.nodes[0].decoderawtransaction(hexlify(txSave.serialize()))
+        txSave.vin[0].scriptSig = hex_str_to_bytes(push_signature)
+        rpc_result = self.nodes[0].decoderawtransaction(bytes_to_hex_str(txSave.serialize()))
         assert_equal(signature_sighash_decoded, rpc_result['vin'][0]['scriptSig']['asm'])
 
         # make sure that the sighash decodes come out correctly for a more complex / lesser used case.
-        txSave.vin[0].scriptSig = unhexlify(push_signature_2)
-        rpc_result = self.nodes[0].decoderawtransaction(hexlify(txSave.serialize()))
+        txSave.vin[0].scriptSig = hex_str_to_bytes(push_signature_2)
+        rpc_result = self.nodes[0].decoderawtransaction(bytes_to_hex_str(txSave.serialize()))
         assert_equal(signature_2_sighash_decoded, rpc_result['vin'][0]['scriptSig']['asm'])
 
         # 2) multisig scriptSig
-        txSave.vin[0].scriptSig = unhexlify('00' + push_signature + push_signature_2)
-        rpc_result = self.nodes[0].decoderawtransaction(hexlify(txSave.serialize()))
+        txSave.vin[0].scriptSig = hex_str_to_bytes('00' + push_signature + push_signature_2)
+        rpc_result = self.nodes[0].decoderawtransaction(bytes_to_hex_str(txSave.serialize()))
         assert_equal('0 ' + signature_sighash_decoded + ' ' + signature_2_sighash_decoded, rpc_result['vin'][0]['scriptSig']['asm'])
 
         # 3) test a scriptSig that contains more than push operations.
         # in fact, it contains an OP_RETURN with data specially crafted to cause improper decode if the code does not catch it.
-        txSave.vin[0].scriptSig = unhexlify('6a143011020701010101010101020601010101010101')
-        rpc_result = self.nodes[0].decoderawtransaction(hexlify(txSave.serialize()))
-        print(hexlify('636174'))
+        txSave.vin[0].scriptSig = hex_str_to_bytes('6a143011020701010101010101020601010101010101')
+        rpc_result = self.nodes[0].decoderawtransaction(bytes_to_hex_str(txSave.serialize()))
         assert_equal('OP_RETURN 3011020701010101010101020601010101010101', rpc_result['vin'][0]['scriptSig']['asm'])
 
     def run_test(self):
diff --git a/qa/rpc-tests/fundrawtransaction.py b/qa/rpc-tests/fundrawtransaction.py
index 0287965b9..4492ea398 100755
--- a/qa/rpc-tests/fundrawtransaction.py
+++ b/qa/rpc-tests/fundrawtransaction.py
@@ -48,7 +48,7 @@ class RawTransactionsTest(BitcoinTestFramework):
 
         watchonly_address = self.nodes[0].getnewaddress()
         watchonly_pubkey = self.nodes[0].validateaddress(watchonly_address)["pubkey"]
-        watchonly_amount = 200
+        watchonly_amount = Decimal(200)
         self.nodes[3].importpubkey(watchonly_pubkey, "", True)
         watchonly_txid = self.nodes[0].sendtoaddress(watchonly_address, watchonly_amount)
         self.nodes[0].sendtoaddress(self.nodes[3].getnewaddress(), watchonly_amount / 10)
@@ -71,7 +71,7 @@ class RawTransactionsTest(BitcoinTestFramework):
         rawtxfund = self.nodes[2].fundrawtransaction(rawtx)
         fee = rawtxfund['fee']
         dec_tx  = self.nodes[2].decoderawtransaction(rawtxfund['hex'])
-        assert_equal(len(dec_tx['vin']) > 0, True) #test if we have enought inputs
+        assert(len(dec_tx['vin']) > 0) #test if we have enought inputs
 
         ##############################
         # simple test with two coins #
@@ -84,7 +84,7 @@ class RawTransactionsTest(BitcoinTestFramework):
         rawtxfund = self.nodes[2].fundrawtransaction(rawtx)
         fee = rawtxfund['fee']
         dec_tx  = self.nodes[2].decoderawtransaction(rawtxfund['hex'])
-        assert_equal(len(dec_tx['vin']) > 0, True) #test if we have enough inputs
+        assert(len(dec_tx['vin']) > 0) #test if we have enough inputs
 
         ##############################
         # simple test with two coins #
@@ -97,7 +97,7 @@ class RawTransactionsTest(BitcoinTestFramework):
         rawtxfund = self.nodes[2].fundrawtransaction(rawtx)
         fee = rawtxfund['fee']
         dec_tx  = self.nodes[2].decoderawtransaction(rawtxfund['hex'])
-        assert_equal(len(dec_tx['vin']) > 0, True)
+        assert(len(dec_tx['vin']) > 0)
         assert_equal(dec_tx['vin'][0]['scriptSig']['hex'], '')
 
 
@@ -116,7 +116,7 @@ class RawTransactionsTest(BitcoinTestFramework):
         for out in dec_tx['vout']:
             totalOut += out['value']
 
-        assert_equal(len(dec_tx['vin']) > 0, True)
+        assert(len(dec_tx['vin']) > 0)
         assert_equal(dec_tx['vin'][0]['scriptSig']['hex'], '')
 
 
@@ -130,7 +130,7 @@ class RawTransactionsTest(BitcoinTestFramework):
                 utx = aUtx
                 break
 
-        assert_equal(utx!=False, True)
+        assert(utx!=False)
 
         inputs  = [ {'txid' : utx['txid'], 'vout' : utx['vout']}]
         outputs = { self.nodes[0].getnewaddress() : 1.0 }
@@ -148,7 +148,6 @@ class RawTransactionsTest(BitcoinTestFramework):
         assert_equal(fee + totalOut, utx['amount']) #compare vin total and totalout+fee
 
 
-
         #####################################################################
         # test a fundrawtransaction with which will not get a change output #
         #####################################################################
@@ -159,7 +158,7 @@ class RawTransactionsTest(BitcoinTestFramework):
                 utx = aUtx
                 break
 
-        assert_equal(utx!=False, True)
+        assert(utx!=False)
 
         inputs  = [ {'txid' : utx['txid'], 'vout' : utx['vout']}]
         outputs = { self.nodes[0].getnewaddress() : Decimal(5.0) - fee - feeTolerance }
@@ -178,7 +177,6 @@ class RawTransactionsTest(BitcoinTestFramework):
         assert_equal(fee + totalOut, utx['amount']) #compare vin total and totalout+fee
 
 
-
         #########################################################################
         # test a fundrawtransaction with a VIN smaller than the required amount #
         #########################################################################
@@ -189,7 +187,7 @@ class RawTransactionsTest(BitcoinTestFramework):
                 utx = aUtx
                 break
 
-        assert_equal(utx!=False, True)
+        assert(utx!=False)
 
         inputs  = [ {'txid' : utx['txid'], 'vout' : utx['vout']}]
         outputs = { self.nodes[0].getnewaddress() : 1.0 }
@@ -209,7 +207,7 @@ 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'])
@@ -234,7 +232,7 @@ class RawTransactionsTest(BitcoinTestFramework):
                 utx2 = aUtx
 
 
-        assert_equal(utx!=False, True)
+        assert(utx!=False)
 
         inputs  = [ {'txid' : utx['txid'], 'vout' : utx['vout']},{'txid' : utx2['txid'], 'vout' : utx2['vout']} ]
         outputs = { self.nodes[0].getnewaddress() : 6.0 }
@@ -249,7 +247,7 @@ 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)
@@ -276,7 +274,7 @@ class RawTransactionsTest(BitcoinTestFramework):
                 utx2 = aUtx
 
 
-        assert_equal(utx!=False, True)
+        assert(utx!=False)
 
         inputs  = [ {'txid' : utx['txid'], 'vout' : utx['vout']},{'txid' : utx2['txid'], 'vout' : utx2['vout']} ]
         outputs = { self.nodes[0].getnewaddress() : 6.0, self.nodes[0].getnewaddress() : 1.0 }
@@ -291,7 +289,7 @@ 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)
@@ -306,14 +304,11 @@ class RawTransactionsTest(BitcoinTestFramework):
         rawtx   = self.nodes[2].createrawtransaction(inputs, outputs)
         dec_tx  = self.nodes[2].decoderawtransaction(rawtx)
 
-        errorString = ""
         try:
             rawtxfund = self.nodes[2].fundrawtransaction(rawtx)
-        except JSONRPCException,e:
-            errorString = e.error['message']
-
-        assert("Insufficient" in errorString)
-
+            raise AssertionError("Spent more than available")
+        except JSONRPCException as e:
+            assert("Insufficient" in e.error['message'])
 
 
         ############################################################
@@ -462,12 +457,11 @@ class RawTransactionsTest(BitcoinTestFramework):
         self.is_network_split=False
         self.sync_all()
 
-        error = False
         try:
             self.nodes[1].sendtoaddress(self.nodes[0].getnewaddress(), 1.2)
-        except:
-            error = True
-        assert(error)
+            raise AssertionError("Wallet unlocked without passphrase")
+        except JSONRPCException as e:
+            assert('walletpassphrase' in e.error['message'])
 
         oldBalance = self.nodes[0].getbalance()
 
@@ -488,7 +482,6 @@ class RawTransactionsTest(BitcoinTestFramework):
         assert_equal(oldBalance+Decimal('51.10000000'), self.nodes[0].getbalance())
 
 
-
         ###############################################
         # multiple (~19) inputs tx test | Compare fee #
         ###############################################
@@ -580,7 +573,7 @@ class RawTransactionsTest(BitcoinTestFramework):
         assert_equal(len(res_dec["vin"]), 1)
         assert_equal(res_dec["vin"][0]["txid"], watchonly_txid)
 
-        assert_equal("fee" in result.keys(), True)
+        assert("fee" in result.keys())
         assert_greater_than(result["changepos"], -1)
 
         ###############################################################
diff --git a/qa/rpc-tests/getblocktemplate_longpoll.py b/qa/rpc-tests/getblocktemplate_longpoll.py
index 3e85957ae..e2a839f71 100755
--- a/qa/rpc-tests/getblocktemplate_longpoll.py
+++ b/qa/rpc-tests/getblocktemplate_longpoll.py
@@ -6,28 +6,6 @@
 from test_framework.test_framework import BitcoinTestFramework
 from test_framework.util import *
 
-
-def check_array_result(object_array, to_match, expected):
-    """
-    Pass in array of JSON objects, a dictionary with key/value pairs
-    to match against, and another dictionary with expected key/value
-    pairs.
-    """
-    num_matched = 0
-    for item in object_array:
-        all_match = True
-        for key,value in to_match.items():
-            if item[key] != value:
-                all_match = False
-        if not all_match:
-            continue
-        for key,value in expected.items():
-            if item[key] != value:
-                raise AssertionError("%s : expected %s=%s"%(str(item), str(key), str(value)))
-            num_matched = num_matched+1
-    if num_matched == 0:
-        raise AssertionError("No objects matched %s"%(str(to_match)))
-
 import threading
 
 class LongpollThread(threading.Thread):
diff --git a/qa/rpc-tests/getblocktemplate_proposals.py b/qa/rpc-tests/getblocktemplate_proposals.py
index f83b5f140..be119031b 100755
--- a/qa/rpc-tests/getblocktemplate_proposals.py
+++ b/qa/rpc-tests/getblocktemplate_proposals.py
@@ -10,28 +10,6 @@ from binascii import a2b_hex, b2a_hex
 from hashlib import sha256
 from struct import pack
 
-
-def check_array_result(object_array, to_match, expected):
-    """
-    Pass in array of JSON objects, a dictionary with key/value pairs
-    to match against, and another dictionary with expected key/value
-    pairs.
-    """
-    num_matched = 0
-    for item in object_array:
-        all_match = True
-        for key,value in to_match.items():
-            if item[key] != value:
-                all_match = False
-        if not all_match:
-            continue
-        for key,value in expected.items():
-            if item[key] != value:
-                raise AssertionError("%s : expected %s=%s"%(str(item), str(key), str(value)))
-            num_matched = num_matched+1
-    if num_matched == 0:
-        raise AssertionError("No objects matched %s"%(str(to_match)))
-
 def b2x(b):
     return b2a_hex(b).decode('ascii')
 
@@ -120,10 +98,7 @@ class GetBlockTemplateProposalTest(BitcoinTestFramework):
 
         # Test 3: Truncated final tx
         lastbyte = txlist[-1].pop()
-        try:
-            assert_template(node, tmpl, txlist, 'n/a')
-        except JSONRPCException:
-            pass  # Expected
+        assert_raises(JSONRPCException, assert_template, node, tmpl, txlist, 'n/a')
         txlist[-1].append(lastbyte)
 
         # Test 4: Add an invalid tx to the end (duplicate of gen tx)
@@ -133,7 +108,7 @@ class GetBlockTemplateProposalTest(BitcoinTestFramework):
 
         # Test 5: Add an invalid tx to the end (non-duplicate)
         txlist.append(bytearray(txlist[0]))
-        txlist[-1][4+1] = b'\xff'
+        txlist[-1][4+1] = 0xff
         assert_template(node, tmpl, txlist, 'bad-txns-inputs-missingorspent')
         txlist.pop()
 
@@ -144,10 +119,7 @@ class GetBlockTemplateProposalTest(BitcoinTestFramework):
 
         # Test 7: Bad tx count
         txlist.append(b'')
-        try:
-            assert_template(node, tmpl, txlist, 'n/a')
-        except JSONRPCException:
-            pass  # Expected
+        assert_raises(JSONRPCException, assert_template, node, tmpl, txlist, 'n/a')
         txlist.pop()
 
         # Test 8: Bad bits
diff --git a/qa/rpc-tests/httpbasics.py b/qa/rpc-tests/httpbasics.py
index eb548aee9..ce62fef46 100755
--- a/qa/rpc-tests/httpbasics.py
+++ b/qa/rpc-tests/httpbasics.py
@@ -9,7 +9,6 @@
 
 from test_framework.test_framework import BitcoinTestFramework
 from test_framework.util import *
-import base64
 
 try:
     import http.client as httplib
@@ -31,71 +30,71 @@ class HTTPBasicsTest (BitcoinTestFramework):
         #################################################
         url = urlparse.urlparse(self.nodes[0].url)
         authpair = url.username + ':' + url.password
-        headers = {"Authorization": "Basic " + base64.b64encode(authpair)}
+        headers = {"Authorization": "Basic " + str_to_b64str(authpair)}
 
         conn = httplib.HTTPConnection(url.hostname, url.port)
         conn.connect()
         conn.request('POST', '/', '{"method": "getbestblockhash"}', headers)
         out1 = conn.getresponse().read()
-        assert_equal('"error":null' in out1, True)
-        assert_equal(conn.sock!=None, True) #according to http/1.1 connection must still be open!
+        assert('"error":null' in out1)
+        assert(conn.sock!=None) #according to http/1.1 connection must still be open!
 
         #send 2nd request without closing connection
         conn.request('POST', '/', '{"method": "getchaintips"}', headers)
         out2 = conn.getresponse().read()
-        assert_equal('"error":null' in out1, True) #must also response with a correct json-rpc message
-        assert_equal(conn.sock!=None, True) #according to http/1.1 connection must still be open!
+        assert('"error":null' in out1) #must also response with a correct json-rpc message
+        assert(conn.sock!=None) #according to http/1.1 connection must still be open!
         conn.close()
 
         #same should be if we add keep-alive because this should be the std. behaviour
-        headers = {"Authorization": "Basic " + base64.b64encode(authpair), "Connection": "keep-alive"}
+        headers = {"Authorization": "Basic " + str_to_b64str(authpair), "Connection": "keep-alive"}
 
         conn = httplib.HTTPConnection(url.hostname, url.port)
         conn.connect()
         conn.request('POST', '/', '{"method": "getbestblockhash"}', headers)
         out1 = conn.getresponse().read()
-        assert_equal('"error":null' in out1, True)
-        assert_equal(conn.sock!=None, True) #according to http/1.1 connection must still be open!
+        assert('"error":null' in out1)
+        assert(conn.sock!=None) #according to http/1.1 connection must still be open!
 
         #send 2nd request without closing connection
         conn.request('POST', '/', '{"method": "getchaintips"}', headers)
         out2 = conn.getresponse().read()
-        assert_equal('"error":null' in out1, True) #must also response with a correct json-rpc message
-        assert_equal(conn.sock!=None, True) #according to http/1.1 connection must still be open!
+        assert('"error":null' in out1) #must also response with a correct json-rpc message
+        assert(conn.sock!=None) #according to http/1.1 connection must still be open!
         conn.close()
 
         #now do the same with "Connection: close"
-        headers = {"Authorization": "Basic " + base64.b64encode(authpair), "Connection":"close"}
+        headers = {"Authorization": "Basic " + str_to_b64str(authpair), "Connection":"close"}
 
         conn = httplib.HTTPConnection(url.hostname, url.port)
         conn.connect()
         conn.request('POST', '/', '{"method": "getbestblockhash"}', headers)
         out1 = conn.getresponse().read()
-        assert_equal('"error":null' in out1, True)
-        assert_equal(conn.sock!=None, False) #now the connection must be closed after the response
+        assert('"error":null' in out1)
+        assert(conn.sock==None) #now the connection must be closed after the response
 
         #node1 (2nd node) is running with disabled keep-alive option
         urlNode1 = urlparse.urlparse(self.nodes[1].url)
         authpair = urlNode1.username + ':' + urlNode1.password
-        headers = {"Authorization": "Basic " + base64.b64encode(authpair)}
+        headers = {"Authorization": "Basic " + str_to_b64str(authpair)}
 
         conn = httplib.HTTPConnection(urlNode1.hostname, urlNode1.port)
         conn.connect()
         conn.request('POST', '/', '{"method": "getbestblockhash"}', headers)
         out1 = conn.getresponse().read()
-        assert_equal('"error":null' in out1, True)
+        assert('"error":null' in out1)
 
         #node2 (third node) is running with standard keep-alive parameters which means keep-alive is on
         urlNode2 = urlparse.urlparse(self.nodes[2].url)
         authpair = urlNode2.username + ':' + urlNode2.password
-        headers = {"Authorization": "Basic " + base64.b64encode(authpair)}
+        headers = {"Authorization": "Basic " + str_to_b64str(authpair)}
 
         conn = httplib.HTTPConnection(urlNode2.hostname, urlNode2.port)
         conn.connect()
         conn.request('POST', '/', '{"method": "getbestblockhash"}', headers)
         out1 = conn.getresponse().read()
-        assert_equal('"error":null' in out1, True)
-        assert_equal(conn.sock!=None, True) #connection must be closed because bitcoind should use keep-alive by default
+        assert('"error":null' in out1)
+        assert(conn.sock!=None) #connection must be closed because bitcoind should use keep-alive by default
 
         # Check excessive request size
         conn = httplib.HTTPConnection(urlNode2.hostname, urlNode2.port)
diff --git a/qa/rpc-tests/invalidblockrequest.py b/qa/rpc-tests/invalidblockrequest.py
index 5f6b1abed..63fe5eae9 100755
--- a/qa/rpc-tests/invalidblockrequest.py
+++ b/qa/rpc-tests/invalidblockrequest.py
@@ -77,9 +77,9 @@ class InvalidBlockRequestTest(ComparisonTestFramework):
         block2 = create_block(self.tip, create_coinbase(height), self.block_time)
         self.block_time += 1
 
-        # chr(81) is OP_TRUE
-        tx1 = create_transaction(self.block1.vtx[0], 0, chr(81), 50*100000000)
-        tx2 = create_transaction(tx1, 0, chr(81), 50*100000000)
+        # b'0x51' is OP_TRUE
+        tx1 = create_transaction(self.block1.vtx[0], 0, b'\x51', 50 * COIN)
+        tx2 = create_transaction(tx1, 0, b'\x51', 50 * COIN)
 
         block2.vtx.extend([tx1, tx2])
         block2.hashMerkleRoot = block2.calc_merkle_root()
@@ -95,7 +95,7 @@ class InvalidBlockRequestTest(ComparisonTestFramework):
         assert(block2_orig.vtx != block2.vtx)
 
         self.tip = block2.sha256
-        yield TestInstance([[block2, RejectResult(16,'bad-txns-duplicate')], [block2_orig, True]])
+        yield TestInstance([[block2, RejectResult(16, b'bad-txns-duplicate')], [block2_orig, True]])
         height += 1
 
         '''
@@ -103,14 +103,14 @@ class InvalidBlockRequestTest(ComparisonTestFramework):
         '''
         block3 = create_block(self.tip, create_coinbase(height), self.block_time)
         self.block_time += 1
-        block3.vtx[0].vout[0].nValue = 100*100000000 # Too high!
+        block3.vtx[0].vout[0].nValue = 100 * COIN # Too high!
         block3.vtx[0].sha256=None
         block3.vtx[0].calc_sha256()
         block3.hashMerkleRoot = block3.calc_merkle_root()
         block3.rehash()
         block3.solve()
 
-        yield TestInstance([[block3, RejectResult(16,'bad-cb-amount')]])
+        yield TestInstance([[block3, RejectResult(16, b'bad-cb-amount')]])
 
 
 if __name__ == '__main__':
diff --git a/qa/rpc-tests/invalidtxrequest.py b/qa/rpc-tests/invalidtxrequest.py
index b2c0d145f..45ae78a48 100755
--- a/qa/rpc-tests/invalidtxrequest.py
+++ b/qa/rpc-tests/invalidtxrequest.py
@@ -61,10 +61,10 @@ class InvalidTxRequestTest(ComparisonTestFramework):
             height += 1
         yield test
 
-        # chr(100) is OP_NOTIF
+        # b'\x64' is OP_NOTIF
         # Transaction will be rejected with code 16 (REJECT_INVALID)
-        tx1 = create_transaction(self.block1.vtx[0], 0, chr(100), 50*100000000)
-        yield TestInstance([[tx1, RejectResult(16, 'mandatory-script-verify-flag-failed')]])
+        tx1 = create_transaction(self.block1.vtx[0], 0, b'\x64', 50 * COIN)
+        yield TestInstance([[tx1, RejectResult(16, b'mandatory-script-verify-flag-failed')]])
 
         # TODO: test further transactions...
 
diff --git a/qa/rpc-tests/keypool.py b/qa/rpc-tests/keypool.py
index c300bbc57..b86c085e0 100755
--- a/qa/rpc-tests/keypool.py
+++ b/qa/rpc-tests/keypool.py
@@ -10,28 +10,6 @@
 from test_framework.test_framework import BitcoinTestFramework
 from test_framework.util import *
 
-
-def check_array_result(object_array, to_match, expected):
-    """
-    Pass in array of JSON objects, a dictionary with key/value pairs
-    to match against, and another dictionary with expected key/value
-    pairs.
-    """
-    num_matched = 0
-    for item in object_array:
-        all_match = True
-        for key,value in to_match.items():
-            if item[key] != value:
-                all_match = False
-        if not all_match:
-            continue
-        for key,value in expected.items():
-            if item[key] != value:
-                raise AssertionError("%s : expected %s=%s"%(str(item), str(key), str(value)))
-            num_matched = num_matched+1
-    if num_matched == 0:
-        raise AssertionError("No objects matched %s"%(str(to_match)))
-
 class KeyPoolTest(BitcoinTestFramework):
 
     def run_test(self):
@@ -46,7 +24,7 @@ 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
@@ -66,13 +44,15 @@ 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
-        nodes[0].walletpassphrase('test', 12000)
+        nodes[0].walletpassphrase('test', 1)
         nodes[0].keypoolrefill(3)
-        nodes[0].walletlock()
+        # test walletpassphrase timeout
+        time.sleep(1.1)
+        assert_equal(nodes[0].getwalletinfo()["unlocked_until"], 0)
 
         # drain them by mining
         nodes[0].generate(1)
@@ -82,7 +62,7 @@ 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 f86f18de9..51a29b48e 100755
--- a/qa/rpc-tests/listtransactions.py
+++ b/qa/rpc-tests/listtransactions.py
@@ -7,65 +7,43 @@
 
 from test_framework.test_framework import BitcoinTestFramework
 from test_framework.util import *
-from test_framework.mininode import CTransaction
-import cStringIO
-import binascii
+from test_framework.mininode import CTransaction, COIN
+from io import BytesIO
 
 def txFromHex(hexstring):
     tx = CTransaction()
-    f = cStringIO.StringIO(binascii.unhexlify(hexstring))
+    f = BytesIO(hex_str_to_bytes(hexstring))
     tx.deserialize(f)
     return tx
 
-def check_array_result(object_array, to_match, expected):
-    """
-    Pass in array of JSON objects, a dictionary with key/value pairs
-    to match against, and another dictionary with expected key/value
-    pairs.
-    """
-    num_matched = 0
-    for item in object_array:
-        all_match = True
-        for key,value in to_match.items():
-            if item[key] != value:
-                all_match = False
-        if not all_match:
-            continue
-        for key,value in expected.items():
-            if item[key] != value:
-                raise AssertionError("%s : expected %s=%s"%(str(item), str(key), str(value)))
-            num_matched = num_matched+1
-    if num_matched == 0:
-        raise AssertionError("No objects matched %s"%(str(to_match)))
-
 class ListTransactionsTest(BitcoinTestFramework):
 
     def run_test(self):
         # Simple send, 0 to 1:
         txid = self.nodes[0].sendtoaddress(self.nodes[1].getnewaddress(), 0.1)
         self.sync_all()
-        check_array_result(self.nodes[0].listtransactions(),
+        assert_array_result(self.nodes[0].listtransactions(),
                            {"txid":txid},
                            {"category":"send","account":"","amount":Decimal("-0.1"),"confirmations":0})
-        check_array_result(self.nodes[1].listtransactions(),
+        assert_array_result(self.nodes[1].listtransactions(),
                            {"txid":txid},
                            {"category":"receive","account":"","amount":Decimal("0.1"),"confirmations":0})
         # mine a block, confirmations should change:
         self.nodes[0].generate(1)
         self.sync_all()
-        check_array_result(self.nodes[0].listtransactions(),
+        assert_array_result(self.nodes[0].listtransactions(),
                            {"txid":txid},
                            {"category":"send","account":"","amount":Decimal("-0.1"),"confirmations":1})
-        check_array_result(self.nodes[1].listtransactions(),
+        assert_array_result(self.nodes[1].listtransactions(),
                            {"txid":txid},
                            {"category":"receive","account":"","amount":Decimal("0.1"),"confirmations":1})
 
         # send-to-self:
         txid = self.nodes[0].sendtoaddress(self.nodes[0].getnewaddress(), 0.2)
-        check_array_result(self.nodes[0].listtransactions(),
+        assert_array_result(self.nodes[0].listtransactions(),
                            {"txid":txid, "category":"send"},
                            {"amount":Decimal("-0.2")})
-        check_array_result(self.nodes[0].listtransactions(),
+        assert_array_result(self.nodes[0].listtransactions(),
                            {"txid":txid, "category":"receive"},
                            {"amount":Decimal("0.2")})
 
@@ -76,28 +54,28 @@ class ListTransactionsTest(BitcoinTestFramework):
                     self.nodes[1].getaccountaddress("toself") : 0.44 }
         txid = self.nodes[1].sendmany("", send_to)
         self.sync_all()
-        check_array_result(self.nodes[1].listtransactions(),
+        assert_array_result(self.nodes[1].listtransactions(),
                            {"category":"send","amount":Decimal("-0.11")},
                            {"txid":txid} )
-        check_array_result(self.nodes[0].listtransactions(),
+        assert_array_result(self.nodes[0].listtransactions(),
                            {"category":"receive","amount":Decimal("0.11")},
                            {"txid":txid} )
-        check_array_result(self.nodes[1].listtransactions(),
+        assert_array_result(self.nodes[1].listtransactions(),
                            {"category":"send","amount":Decimal("-0.22")},
                            {"txid":txid} )
-        check_array_result(self.nodes[1].listtransactions(),
+        assert_array_result(self.nodes[1].listtransactions(),
                            {"category":"receive","amount":Decimal("0.22")},
                            {"txid":txid} )
-        check_array_result(self.nodes[1].listtransactions(),
+        assert_array_result(self.nodes[1].listtransactions(),
                            {"category":"send","amount":Decimal("-0.33")},
                            {"txid":txid} )
-        check_array_result(self.nodes[0].listtransactions(),
+        assert_array_result(self.nodes[0].listtransactions(),
                            {"category":"receive","amount":Decimal("0.33")},
                            {"txid":txid, "account" : "from1"} )
-        check_array_result(self.nodes[1].listtransactions(),
+        assert_array_result(self.nodes[1].listtransactions(),
                            {"category":"send","amount":Decimal("-0.44")},
                            {"txid":txid, "account" : ""} )
-        check_array_result(self.nodes[1].listtransactions(),
+        assert_array_result(self.nodes[1].listtransactions(),
                            {"category":"receive","amount":Decimal("0.44")},
                            {"txid":txid, "account" : "toself"} )
 
@@ -107,7 +85,7 @@ class ListTransactionsTest(BitcoinTestFramework):
         self.nodes[1].generate(1)
         self.sync_all()
         assert(len(self.nodes[0].listtransactions("watchonly", 100, 0, False)) == 0)
-        check_array_result(self.nodes[0].listtransactions("watchonly", 100, 0, True),
+        assert_array_result(self.nodes[0].listtransactions("watchonly", 100, 0, True),
                            {"category":"receive","amount":Decimal("0.1")},
                            {"txid":txid, "account" : "watchonly"} )
 
@@ -135,9 +113,9 @@ class ListTransactionsTest(BitcoinTestFramework):
         # 1. Chain a few transactions that don't opt-in.
         txid_1 = self.nodes[0].sendtoaddress(self.nodes[1].getnewaddress(), 1)
         assert(not is_opt_in(self.nodes[0], txid_1))
-        check_array_result(self.nodes[0].listtransactions(), {"txid": txid_1}, {"bip125-replaceable":"no"})
+        assert_array_result(self.nodes[0].listtransactions(), {"txid": txid_1}, {"bip125-replaceable":"no"})
         sync_mempools(self.nodes)
-        check_array_result(self.nodes[1].listtransactions(), {"txid": txid_1}, {"bip125-replaceable":"no"})
+        assert_array_result(self.nodes[1].listtransactions(), {"txid": txid_1}, {"bip125-replaceable":"no"})
 
         # Tx2 will build off txid_1, still not opting in to RBF.
         utxo_to_use = get_unconfirmed_utxo_entry(self.nodes[1], txid_1)
@@ -151,9 +129,9 @@ class ListTransactionsTest(BitcoinTestFramework):
 
         # ...and check the result
         assert(not is_opt_in(self.nodes[1], txid_2))
-        check_array_result(self.nodes[1].listtransactions(), {"txid": txid_2}, {"bip125-replaceable":"no"})
+        assert_array_result(self.nodes[1].listtransactions(), {"txid": txid_2}, {"bip125-replaceable":"no"})
         sync_mempools(self.nodes)
-        check_array_result(self.nodes[0].listtransactions(), {"txid": txid_2}, {"bip125-replaceable":"no"})
+        assert_array_result(self.nodes[0].listtransactions(), {"txid": txid_2}, {"bip125-replaceable":"no"})
 
         # Tx3 will opt-in to RBF
         utxo_to_use = get_unconfirmed_utxo_entry(self.nodes[0], txid_2)
@@ -162,14 +140,14 @@ class ListTransactionsTest(BitcoinTestFramework):
         tx3 = self.nodes[0].createrawtransaction(inputs, outputs)
         tx3_modified = txFromHex(tx3)
         tx3_modified.vin[0].nSequence = 0
-        tx3 = binascii.hexlify(tx3_modified.serialize()).decode('utf-8')
+        tx3 = bytes_to_hex_str(tx3_modified.serialize())
         tx3_signed = self.nodes[0].signrawtransaction(tx3)['hex']
         txid_3 = self.nodes[0].sendrawtransaction(tx3_signed)
 
         assert(is_opt_in(self.nodes[0], txid_3))
-        check_array_result(self.nodes[0].listtransactions(), {"txid": txid_3}, {"bip125-replaceable":"yes"})
+        assert_array_result(self.nodes[0].listtransactions(), {"txid": txid_3}, {"bip125-replaceable":"yes"})
         sync_mempools(self.nodes)
-        check_array_result(self.nodes[1].listtransactions(), {"txid": txid_3}, {"bip125-replaceable":"yes"})
+        assert_array_result(self.nodes[1].listtransactions(), {"txid": txid_3}, {"bip125-replaceable":"yes"})
 
         # Tx4 will chain off tx3.  Doesn't signal itself, but depends on one
         # that does.
@@ -181,21 +159,21 @@ class ListTransactionsTest(BitcoinTestFramework):
         txid_4 = self.nodes[1].sendrawtransaction(tx4_signed)
 
         assert(not is_opt_in(self.nodes[1], txid_4))
-        check_array_result(self.nodes[1].listtransactions(), {"txid": txid_4}, {"bip125-replaceable":"yes"})
+        assert_array_result(self.nodes[1].listtransactions(), {"txid": txid_4}, {"bip125-replaceable":"yes"})
         sync_mempools(self.nodes)
-        check_array_result(self.nodes[0].listtransactions(), {"txid": txid_4}, {"bip125-replaceable":"yes"})
+        assert_array_result(self.nodes[0].listtransactions(), {"txid": txid_4}, {"bip125-replaceable":"yes"})
 
         # Replace tx3, and check that tx4 becomes unknown
         tx3_b = tx3_modified
-        tx3_b.vout[0].nValue -= 0.004*100000000 # bump the fee
-        tx3_b = binascii.hexlify(tx3_b.serialize()).decode('utf-8')
+        tx3_b.vout[0].nValue -= int(Decimal("0.004") * COIN) # bump the fee
+        tx3_b = bytes_to_hex_str(tx3_b.serialize())
         tx3_b_signed = self.nodes[0].signrawtransaction(tx3_b)['hex']
         txid_3b = self.nodes[0].sendrawtransaction(tx3_b_signed, True)
         assert(is_opt_in(self.nodes[0], txid_3b))
 
-        check_array_result(self.nodes[0].listtransactions(), {"txid": txid_4}, {"bip125-replaceable":"unknown"})
+        assert_array_result(self.nodes[0].listtransactions(), {"txid": txid_4}, {"bip125-replaceable":"unknown"})
         sync_mempools(self.nodes)
-        check_array_result(self.nodes[1].listtransactions(), {"txid": txid_4}, {"bip125-replaceable":"unknown"})
+        assert_array_result(self.nodes[1].listtransactions(), {"txid": txid_4}, {"bip125-replaceable":"unknown"})
 
         # Check gettransaction as well:
         for n in self.nodes[0:2]:
diff --git a/qa/rpc-tests/maxuploadtarget.py b/qa/rpc-tests/maxuploadtarget.py
index 4d6b343f7..584b528a6 100755
--- a/qa/rpc-tests/maxuploadtarget.py
+++ b/qa/rpc-tests/maxuploadtarget.py
@@ -176,9 +176,9 @@ class MaxUploadTest(BitcoinTestFramework):
         getdata_request.inv.append(CInv(2, big_old_block))
 
         max_bytes_per_day = 200*1024*1024
-        daily_buffer = 144 * 1000000
+        daily_buffer = 144 * MAX_BLOCK_SIZE
         max_bytes_available = max_bytes_per_day - daily_buffer
-        success_count = max_bytes_available / old_block_size
+        success_count = max_bytes_available // old_block_size
 
         # 144MB will be reserved for relaying new blocks, so expect this to
         # succeed for ~70 tries.
diff --git a/qa/rpc-tests/mempool_limit.py b/qa/rpc-tests/mempool_limit.py
index 7914ceea2..c19a63c69 100755
--- a/qa/rpc-tests/mempool_limit.py
+++ b/qa/rpc-tests/mempool_limit.py
@@ -38,7 +38,6 @@ class MempoolLimitTest(BitcoinTestFramework):
         self.nodes[0].settxfee(0) # return to automatic fee selection
         txFS = self.nodes[0].signrawtransaction(txF['hex'])
         txid = self.nodes[0].sendrawtransaction(txFS['hex'])
-        self.nodes[0].lockunspent(True, [us0])
 
         relayfee = self.nodes[0].getnetworkinfo()['relayfee']
         base_fee = relayfee*100
diff --git a/qa/rpc-tests/mempool_packages.py b/qa/rpc-tests/mempool_packages.py
index 47c1028b9..bc3f9e051 100755
--- a/qa/rpc-tests/mempool_packages.py
+++ b/qa/rpc-tests/mempool_packages.py
@@ -7,6 +7,7 @@
 
 from test_framework.test_framework import BitcoinTestFramework
 from test_framework.util import *
+from test_framework.mininode import COIN
 
 MAX_ANCESTORS = 25
 MAX_DESCENDANTS = 25
@@ -59,13 +60,12 @@ class MempoolPackagesTest(BitcoinTestFramework):
         descendant_count = 1
         descendant_fees = 0
         descendant_size = 0
-        SATOSHIS = 100000000
 
         for x in reversed(chain):
             assert_equal(mempool[x]['descendantcount'], descendant_count)
             descendant_fees += mempool[x]['fee']
             assert_equal(mempool[x]['modifiedfee'], mempool[x]['fee'])
-            assert_equal(mempool[x]['descendantfees'], SATOSHIS*descendant_fees)
+            assert_equal(mempool[x]['descendantfees'], descendant_fees * COIN)
             descendant_size += mempool[x]['size']
             assert_equal(mempool[x]['descendantsize'], descendant_size)
             descendant_count += 1
@@ -78,7 +78,7 @@ class MempoolPackagesTest(BitcoinTestFramework):
         descendant_fees = 0
         for x in reversed(chain):
             descendant_fees += mempool[x]['fee']
-            assert_equal(mempool[x]['descendantfees'], SATOSHIS*descendant_fees+1000)
+            assert_equal(mempool[x]['descendantfees'], descendant_fees * COIN + 1000)
 
         # Adding one more transaction on to the chain should fail.
         try:
@@ -106,7 +106,7 @@ class MempoolPackagesTest(BitcoinTestFramework):
             descendant_fees += mempool[x]['fee']
             if (x == chain[-1]):
                 assert_equal(mempool[x]['modifiedfee'], mempool[x]['fee']+satoshi_round(0.00002))
-            assert_equal(mempool[x]['descendantfees'], SATOSHIS*descendant_fees+2000)
+            assert_equal(mempool[x]['descendantfees'], descendant_fees * COIN + 2000)
 
         # TODO: check that node1's mempool is as expected
 
diff --git a/qa/rpc-tests/multi_rpc.py b/qa/rpc-tests/multi_rpc.py
index 2452b7731..afb18cf3d 100755
--- a/qa/rpc-tests/multi_rpc.py
+++ b/qa/rpc-tests/multi_rpc.py
@@ -53,7 +53,7 @@ class HTTPBasicsTest (BitcoinTestFramework):
         password2 = "8/F3uMDw4KSEbw96U3CA1C4X05dkHDN2BPFjTgZW4KI="
         authpairnew = "rt:"+password
 
-        headers = {"Authorization": "Basic " + base64.b64encode(authpair)}
+        headers = {"Authorization": "Basic " + str_to_b64str(authpair)}
 
         conn = httplib.HTTPConnection(url.hostname, url.port)
         conn.connect()
@@ -63,7 +63,7 @@ class HTTPBasicsTest (BitcoinTestFramework):
         conn.close()
         
         #Use new authpair to confirm both work
-        headers = {"Authorization": "Basic " + base64.b64encode(authpairnew)}
+        headers = {"Authorization": "Basic " + str_to_b64str(authpairnew)}
 
         conn = httplib.HTTPConnection(url.hostname, url.port)
         conn.connect()
@@ -74,7 +74,7 @@ class HTTPBasicsTest (BitcoinTestFramework):
 
         #Wrong login name with rt's password
         authpairnew = "rtwrong:"+password
-        headers = {"Authorization": "Basic " + base64.b64encode(authpairnew)}
+        headers = {"Authorization": "Basic " + str_to_b64str(authpairnew)}
 
         conn = httplib.HTTPConnection(url.hostname, url.port)
         conn.connect()
@@ -85,7 +85,7 @@ class HTTPBasicsTest (BitcoinTestFramework):
 
         #Wrong password for rt
         authpairnew = "rt:"+password+"wrong"
-        headers = {"Authorization": "Basic " + base64.b64encode(authpairnew)}
+        headers = {"Authorization": "Basic " + str_to_b64str(authpairnew)}
 
         conn = httplib.HTTPConnection(url.hostname, url.port)
         conn.connect()
@@ -96,7 +96,7 @@ class HTTPBasicsTest (BitcoinTestFramework):
 
         #Correct for rt2
         authpairnew = "rt2:"+password2
-        headers = {"Authorization": "Basic " + base64.b64encode(authpairnew)}
+        headers = {"Authorization": "Basic " + str_to_b64str(authpairnew)}
 
         conn = httplib.HTTPConnection(url.hostname, url.port)
         conn.connect()
@@ -107,7 +107,7 @@ class HTTPBasicsTest (BitcoinTestFramework):
 
         #Wrong password for rt2
         authpairnew = "rt2:"+password2+"wrong"
-        headers = {"Authorization": "Basic " + base64.b64encode(authpairnew)}
+        headers = {"Authorization": "Basic " + str_to_b64str(authpairnew)}
 
         conn = httplib.HTTPConnection(url.hostname, url.port)
         conn.connect()
@@ -117,6 +117,5 @@ class HTTPBasicsTest (BitcoinTestFramework):
         conn.close()
 
 
-
 if __name__ == '__main__':
     HTTPBasicsTest ().main ()
diff --git a/qa/rpc-tests/p2p-acceptblock.py b/qa/rpc-tests/p2p-acceptblock.py
index 23872d849..3b569b29c 100755
--- a/qa/rpc-tests/p2p-acceptblock.py
+++ b/qa/rpc-tests/p2p-acceptblock.py
@@ -150,7 +150,7 @@ class AcceptBlockTest(BitcoinTestFramework):
         # 2. Send one block that builds on each tip.
         # This should be accepted.
         blocks_h2 = []  # the height 2 blocks on each node's chain
-        block_time = time.time() + 1
+        block_time = int(time.time()) + 1
         for i in xrange(2):
             blocks_h2.append(create_block(tips[i], create_coinbase(2), block_time))
             blocks_h2[i].solve()
diff --git a/qa/rpc-tests/p2p-fullblocktest.py b/qa/rpc-tests/p2p-fullblocktest.py
index 28cc2474f..f3ed80605 100755
--- a/qa/rpc-tests/p2p-fullblocktest.py
+++ b/qa/rpc-tests/p2p-fullblocktest.py
@@ -34,7 +34,7 @@ class FullBlockTest(ComparisonTestFramework):
         self.num_nodes = 1
         self.block_heights = {}
         self.coinbase_key = CECKey()
-        self.coinbase_key.set_secretbytes(bytes("horsebattery"))
+        self.coinbase_key.set_secretbytes(b"horsebattery")
         self.coinbase_pubkey = self.coinbase_key.get_pubkey()
         self.block_time = int(time.time())+1
         self.tip = None
@@ -71,7 +71,7 @@ class FullBlockTest(ComparisonTestFramework):
         block = create_block(base_block_hash, coinbase, self.block_time)
         if (spend != None):
             tx = CTransaction()
-            tx.vin.append(CTxIn(COutPoint(spend.tx.sha256, spend.n), "", 0xffffffff))  # no signature yet
+            tx.vin.append(CTxIn(COutPoint(spend.tx.sha256, spend.n), b"", 0xffffffff))  # no signature yet
             # This copies the java comparison tool testing behavior: the first
             # txout has a garbage scriptPubKey, "to make sure we're not
             # pre-verifying too much" (?)
@@ -81,7 +81,7 @@ class FullBlockTest(ComparisonTestFramework):
             else:
                 tx.vout.append(CTxOut(1, script))
             # Now sign it if necessary
-            scriptSig = ""
+            scriptSig = b""
             scriptPubKey = bytearray(spend.tx.vout[spend.n].scriptPubKey)
             if (scriptPubKey[0] == OP_TRUE):  # looks like an anyone-can-spend
                 scriptSig = CScript([OP_TRUE])
@@ -226,7 +226,7 @@ class FullBlockTest(ComparisonTestFramework):
         #                      \-> b3 (1) -> b4 (2)
         tip(6)
         block(9, spend=out4, additional_coinbase_value=1)
-        yield rejected(RejectResult(16, 'bad-cb-amount'))
+        yield rejected(RejectResult(16, b'bad-cb-amount'))
 
         
         # Create a fork that ends in a block with too much fee (the one that causes the reorg)
@@ -238,7 +238,7 @@ class FullBlockTest(ComparisonTestFramework):
         yield rejected()
 
         block(11, spend=out4, additional_coinbase_value=1)
-        yield rejected(RejectResult(16, 'bad-cb-amount'))
+        yield rejected(RejectResult(16, b'bad-cb-amount'))
 
 
         # Try again, but with a valid fork first
@@ -270,7 +270,7 @@ class FullBlockTest(ComparisonTestFramework):
         #                      \-> b3 (1) -> b4 (2)
         
         # Test that a block with a lot of checksigs is okay
-        lots_of_checksigs = CScript([OP_CHECKSIG] * (1000000 / 50 - 1))
+        lots_of_checksigs = CScript([OP_CHECKSIG] * (1000000 // 50 - 1))
         tip(13)
         block(15, spend=out5, script=lots_of_checksigs)
         yield accepted()
@@ -278,9 +278,9 @@ class FullBlockTest(ComparisonTestFramework):
 
         # Test that a block with too many checksigs is rejected
         out6 = get_spendable_output()
-        too_many_checksigs = CScript([OP_CHECKSIG] * (1000000 / 50))
+        too_many_checksigs = CScript([OP_CHECKSIG] * (1000000 // 50))
         block(16, spend=out6, script=too_many_checksigs)
-        yield rejected(RejectResult(16, 'bad-blk-sigops'))
+        yield rejected(RejectResult(16, b'bad-blk-sigops'))
 
 
         # Attempt to spend a transaction created on a different fork
@@ -289,7 +289,7 @@ class FullBlockTest(ComparisonTestFramework):
         #                      \-> b3 (1) -> b4 (2)
         tip(15)
         block(17, spend=txout_b3)
-        yield rejected(RejectResult(16, 'bad-txns-inputs-missingorspent'))
+        yield rejected(RejectResult(16, b'bad-txns-inputs-missingorspent'))
 
         # Attempt to spend a transaction created on a different fork (on a fork this time)
         #     genesis -> b1 (0) -> b2 (1) -> b5 (2) -> b6  (3)
@@ -310,7 +310,7 @@ class FullBlockTest(ComparisonTestFramework):
         tip(15)
         out7 = get_spendable_output()
         block(20, spend=out7)
-        yield rejected(RejectResult(16, 'bad-txns-premature-spend-of-coinbase'))
+        yield rejected(RejectResult(16, b'bad-txns-premature-spend-of-coinbase'))
 
         # Attempt to spend a coinbase at depth too low (on a fork this time)
         #     genesis -> b1 (0) -> b2 (1) -> b5 (2) -> b6  (3)
@@ -334,7 +334,7 @@ class FullBlockTest(ComparisonTestFramework):
         old_hash = b23.sha256
         tx = CTransaction()
         script_length = MAX_BLOCK_SIZE - len(b23.serialize()) - 69
-        script_output = CScript([chr(0)*script_length])
+        script_output = CScript([b'\x00' * script_length])
         tx.vout.append(CTxOut(0, script_output))
         tx.vin.append(CTxIn(COutPoint(b23.vtx[1].sha256, 1)))
         b23 = update_block(23, [tx])
@@ -346,11 +346,11 @@ class FullBlockTest(ComparisonTestFramework):
         tip(15)
         b24 = block(24, spend=out6)
         script_length = MAX_BLOCK_SIZE - len(b24.serialize()) - 69
-        script_output = CScript([chr(0)*(script_length+1)])
+        script_output = CScript([b'\x00' * (script_length+1)])
         tx.vout = [CTxOut(0, script_output)]
         b24 = update_block(24, [tx])
         assert_equal(len(b24.serialize()), MAX_BLOCK_SIZE+1)
-        yield rejected(RejectResult(16, 'bad-blk-length'))
+        yield rejected(RejectResult(16, b'bad-blk-length'))
 
         b25 = block(25, spend=out7)
         yield rejected()
@@ -362,12 +362,12 @@ class FullBlockTest(ComparisonTestFramework):
         #                      \-> b3 (1) -> b4 (2)
         tip(15)
         b26 = block(26, spend=out6)
-        b26.vtx[0].vin[0].scriptSig = chr(0)
+        b26.vtx[0].vin[0].scriptSig = b'\x00'
         b26.vtx[0].rehash()
         # update_block causes the merkle root to get updated, even with no new
         # transactions, and updates the required state.
         b26 = update_block(26, [])
-        yield rejected(RejectResult(16, 'bad-cb-length'))
+        yield rejected(RejectResult(16, b'bad-cb-length'))
 
         # Extend the b26 chain to make sure bitcoind isn't accepting b26
         b27 = block(27, spend=out7)
@@ -376,10 +376,10 @@ class FullBlockTest(ComparisonTestFramework):
         # Now try a too-large-coinbase script
         tip(15)
         b28 = block(28, spend=out6)
-        b28.vtx[0].vin[0].scriptSig = chr(0)*101
+        b28.vtx[0].vin[0].scriptSig = b'\x00' * 101
         b28.vtx[0].rehash()
         b28 = update_block(28, [])
-        yield rejected(RejectResult(16, 'bad-cb-length'))
+        yield rejected(RejectResult(16, b'bad-cb-length'))
 
         # Extend the b28 chain to make sure bitcoind isn't accepted b28
         b29 = block(29, spend=out7)
@@ -391,7 +391,7 @@ class FullBlockTest(ComparisonTestFramework):
         # b30 has a max-sized coinbase scriptSig.
         tip(23)
         b30 = block(30)
-        b30.vtx[0].vin[0].scriptSig = chr(0)*100
+        b30.vtx[0].vin[0].scriptSig = b'\x00' * 100
         b30.vtx[0].rehash()
         b30 = update_block(30, [])
         yield accepted()
diff --git a/qa/rpc-tests/prioritise_transaction.py b/qa/rpc-tests/prioritise_transaction.py
index 4a79d38da..f8d9063b4 100755
--- a/qa/rpc-tests/prioritise_transaction.py
+++ b/qa/rpc-tests/prioritise_transaction.py
@@ -9,8 +9,7 @@
 
 from test_framework.test_framework import BitcoinTestFramework
 from test_framework.util import *
-
-COIN = 100000000
+from test_framework.mininode import COIN, MAX_BLOCK_SIZE
 
 class PrioritiseTransactionTest(BitcoinTestFramework):
 
@@ -29,14 +28,29 @@ class PrioritiseTransactionTest(BitcoinTestFramework):
         self.relayfee = self.nodes[0].getnetworkinfo()['relayfee']
 
     def run_test(self):
-        utxos = create_confirmed_utxos(self.relayfee, self.nodes[0], 90)
+        utxo_count = 90
+        utxos = create_confirmed_utxos(self.relayfee, self.nodes[0], utxo_count)
         base_fee = self.relayfee*100 # our transactions are smaller than 100kb
         txids = []
 
         # Create 3 batches of transactions at 3 different fee rate levels
+        range_size = utxo_count // 3
         for i in xrange(3):
             txids.append([])
-            txids[i] = create_lots_of_big_transactions(self.nodes[0], self.txouts, utxos[30*i:30*i+30], (i+1)*base_fee)
+            start_range = i * range_size
+            end_range = start_range + range_size
+            txids[i] = create_lots_of_big_transactions(self.nodes[0], self.txouts, utxos[start_range:end_range], (i+1)*base_fee)
+
+        # Make sure that the size of each group of transactions exceeds
+        # MAX_BLOCK_SIZE -- otherwise the test needs to be revised to create
+        # more transactions.
+        mempool = self.nodes[0].getrawmempool(True)
+        sizes = [0, 0, 0]
+        for i in xrange(3):
+            for j in txids[i]:
+                assert(j in mempool)
+                sizes[i] += mempool[j]['size']
+            assert(sizes[i] > MAX_BLOCK_SIZE) # Fail => raise utxo_count
 
         # add a fee delta to something in the cheapest bucket and make sure it gets mined
         # also check that a different entry in the cheapest bucket is NOT mined (lower
@@ -47,7 +61,7 @@ class PrioritiseTransactionTest(BitcoinTestFramework):
         self.nodes[0].generate(1)
 
         mempool = self.nodes[0].getrawmempool()
-        print "Assert that prioritised transasction was mined"
+        print "Assert that prioritised transaction was mined"
         assert(txids[0][0] not in mempool)
         assert(txids[0][1] in mempool)
 
@@ -60,7 +74,7 @@ class PrioritiseTransactionTest(BitcoinTestFramework):
         assert(high_fee_tx != None)
 
         # Add a prioritisation before a tx is in the mempool (de-prioritising a
-        # high-fee transaction).
+        # high-fee transaction so that it's now low fee).
         self.nodes[0].prioritisetransaction(high_fee_tx, -1e15, -int(2*base_fee*COIN))
 
         # Add everything back to mempool
@@ -70,8 +84,11 @@ class PrioritiseTransactionTest(BitcoinTestFramework):
         mempool = self.nodes[0].getrawmempool()
         assert(high_fee_tx in mempool)
 
-        # Now verify the high feerate transaction isn't mined.
-        self.nodes[0].generate(5)
+        # Now verify the modified-high feerate transaction isn't mined before
+        # the other high fee transactions. Keep mining until our mempool has
+        # decreased by all the high fee size that we calculated above.
+        while (self.nodes[0].getmempoolinfo()['bytes'] > sizes[0] + sizes[1]):
+            self.nodes[0].generate(1)
 
         # High fee transaction should not have been mined, but other high fee rate
         # transactions should have been.
diff --git a/qa/rpc-tests/proxy_test.py b/qa/rpc-tests/proxy_test.py
index 7f77e664d..e94111ac7 100755
--- a/qa/rpc-tests/proxy_test.py
+++ b/qa/rpc-tests/proxy_test.py
@@ -77,7 +77,7 @@ class ProxyTest(BitcoinTestFramework):
         assert(isinstance(cmd, Socks5Command))
         # Note: bitcoind's SOCKS5 implementation only sends atyp DOMAINNAME, even if connecting directly to IPv4/IPv6
         assert_equal(cmd.atyp, AddressType.DOMAINNAME)
-        assert_equal(cmd.addr, "15.61.23.23")
+        assert_equal(cmd.addr, b"15.61.23.23")
         assert_equal(cmd.port, 1234)
         if not auth:
             assert_equal(cmd.username, None)
@@ -90,7 +90,7 @@ class ProxyTest(BitcoinTestFramework):
         assert(isinstance(cmd, Socks5Command))
         # Note: bitcoind's SOCKS5 implementation only sends atyp DOMAINNAME, even if connecting directly to IPv4/IPv6
         assert_equal(cmd.atyp, AddressType.DOMAINNAME)
-        assert_equal(cmd.addr, "1233:3432:2434:2343:3234:2345:6546:4534")
+        assert_equal(cmd.addr, b"1233:3432:2434:2343:3234:2345:6546:4534")
         assert_equal(cmd.port, 5443)
         if not auth:
             assert_equal(cmd.username, None)
@@ -103,7 +103,7 @@ class ProxyTest(BitcoinTestFramework):
             cmd = proxies[2].queue.get()
             assert(isinstance(cmd, Socks5Command))
             assert_equal(cmd.atyp, AddressType.DOMAINNAME)
-            assert_equal(cmd.addr, "bitcoinostk4e4re.onion")
+            assert_equal(cmd.addr, b"bitcoinostk4e4re.onion")
             assert_equal(cmd.port, 8333)
             if not auth:
                 assert_equal(cmd.username, None)
@@ -115,7 +115,7 @@ class ProxyTest(BitcoinTestFramework):
         cmd = proxies[3].queue.get()
         assert(isinstance(cmd, Socks5Command))
         assert_equal(cmd.atyp, AddressType.DOMAINNAME)
-        assert_equal(cmd.addr, "node.noumenon")
+        assert_equal(cmd.addr, b"node.noumenon")
         assert_equal(cmd.port, 8333)
         if not auth:
             assert_equal(cmd.username, None)
diff --git a/qa/rpc-tests/pruning.py b/qa/rpc-tests/pruning.py
index b0f4b88ae..eccd157e5 100755
--- a/qa/rpc-tests/pruning.py
+++ b/qa/rpc-tests/pruning.py
@@ -15,7 +15,7 @@ from test_framework.test_framework import BitcoinTestFramework
 from test_framework.util import *
 
 def calc_usage(blockdir):
-    return sum(os.path.getsize(blockdir+f) for f in os.listdir(blockdir) if os.path.isfile(blockdir+f))/(1024*1024)
+    return sum(os.path.getsize(blockdir+f) for f in os.listdir(blockdir) if os.path.isfile(blockdir+f)) / (1024. * 1024.)
 
 class PruneTest(BitcoinTestFramework):
 
@@ -56,7 +56,7 @@ class PruneTest(BitcoinTestFramework):
         self.nodes[1].generate(200)
         sync_blocks(self.nodes[0:2])
         self.nodes[0].generate(150)
-        # Then mine enough full blocks to create more than 550MB of data
+        # Then mine enough full blocks to create more than 550MiB of data
         for i in xrange(645):
             self.mine_full_block(self.nodes[0], self.address[0])
 
@@ -66,7 +66,7 @@ class PruneTest(BitcoinTestFramework):
         if not os.path.isfile(self.prunedir+"blk00000.dat"):
             raise AssertionError("blk00000.dat is missing, pruning too early")
         print "Success"
-        print "Though we're already using more than 550MB, current usage:", calc_usage(self.prunedir)
+        print "Though we're already using more than 550MiB, current usage:", calc_usage(self.prunedir)
         print "Mining 25 more blocks should cause the first block file to be pruned"
         # Pruning doesn't run until we're allocating another chunk, 20 full blocks past the height cutoff will ensure this
         for i in xrange(25):
@@ -311,7 +311,7 @@ class PruneTest(BitcoinTestFramework):
         #                   \                 \
         #                    ++...++(1044)     ..
         #
-        # N0    ********************(1032) @@...@@@(1552) 
+        # N0    ********************(1032) @@...@@@(1552)
         #                                 \
         #                                  *...**(1320)
 
diff --git a/qa/rpc-tests/rawtransactions.py b/qa/rpc-tests/rawtransactions.py
index dd9e5e28a..e38ef6c8b 100755
--- a/qa/rpc-tests/rawtransactions.py
+++ b/qa/rpc-tests/rawtransactions.py
@@ -56,13 +56,13 @@ class RawTransactionsTest(BitcoinTestFramework):
         rawtx   = self.nodes[2].createrawtransaction(inputs, outputs)
         rawtx   = self.nodes[2].signrawtransaction(rawtx)
 
-        errorString = ""
         try:
             rawtx   = self.nodes[2].sendrawtransaction(rawtx['hex'])
-        except JSONRPCException,e:
-            errorString = e.error['message']
+        except JSONRPCException as e:
+            assert("Missing inputs" in e.error['message'])
+        else:
+            assert(False)
 
-        assert("Missing inputs" in errorString)
 
         #########################
         # RAW TX MULTISIG TESTS #
@@ -88,8 +88,6 @@ class RawTransactionsTest(BitcoinTestFramework):
         assert_equal(self.nodes[2].getbalance(), bal+Decimal('1.20000000')) #node2 has both keys of the 2of2 ms addr., tx should affect the balance
 
 
-
-
         # 2of3 test from different nodes
         bal = self.nodes[2].getbalance()
         addr1 = self.nodes[1].getnewaddress()
diff --git a/qa/rpc-tests/receivedby.py b/qa/rpc-tests/receivedby.py
index 18af0e810..15ef71a58 100755
--- a/qa/rpc-tests/receivedby.py
+++ b/qa/rpc-tests/receivedby.py
@@ -25,32 +25,6 @@ def get_sub_array_from_array(object_array, to_match):
         return item
     return []
 
-def check_array_result(object_array, to_match, expected, should_not_find = False):
-    """
-        Pass in array of JSON objects, a dictionary with key/value pairs
-        to match against, and another dictionary with expected key/value
-        pairs.
-        If the should_not_find flag is true, to_match should not be found in object_array
-        """
-    if should_not_find == True:
-        expected = { }
-    num_matched = 0
-    for item in object_array:
-        all_match = True
-        for key,value in to_match.items():
-            if item[key] != value:
-                all_match = False
-        if not all_match:
-            continue
-        for key,value in expected.items():
-            if item[key] != value:
-                raise AssertionError("%s : expected %s=%s"%(str(item), str(key), str(value)))
-            num_matched = num_matched+1
-    if num_matched == 0 and should_not_find != True:
-        raise AssertionError("No objects matched %s"%(str(to_match)))
-    if num_matched > 0 and should_not_find == True:
-        raise AssertionError("Objects was matched %s"%(str(to_match)))
-
 class ReceivedByTest(BitcoinTestFramework):
 
     def run_test(self):
@@ -63,26 +37,26 @@ class ReceivedByTest(BitcoinTestFramework):
         self.sync_all()
 
         #Check not listed in listreceivedbyaddress because has 0 confirmations
-        check_array_result(self.nodes[1].listreceivedbyaddress(),
+        assert_array_result(self.nodes[1].listreceivedbyaddress(),
                            {"address":addr},
                            { },
                            True)
         #Bury Tx under 10 block so it will be returned by listreceivedbyaddress
         self.nodes[1].generate(10)
         self.sync_all()
-        check_array_result(self.nodes[1].listreceivedbyaddress(),
+        assert_array_result(self.nodes[1].listreceivedbyaddress(),
                            {"address":addr},
                            {"address":addr, "account":"", "amount":Decimal("0.1"), "confirmations":10, "txids":[txid,]})
         #With min confidence < 10
-        check_array_result(self.nodes[1].listreceivedbyaddress(5),
+        assert_array_result(self.nodes[1].listreceivedbyaddress(5),
                            {"address":addr},
                            {"address":addr, "account":"", "amount":Decimal("0.1"), "confirmations":10, "txids":[txid,]})
         #With min confidence > 10, should not find Tx
-        check_array_result(self.nodes[1].listreceivedbyaddress(11),{"address":addr},{ },True)
+        assert_array_result(self.nodes[1].listreceivedbyaddress(11),{"address":addr},{ },True)
 
         #Empty Tx
         addr = self.nodes[1].getnewaddress()
-        check_array_result(self.nodes[1].listreceivedbyaddress(0,True),
+        assert_array_result(self.nodes[1].listreceivedbyaddress(0,True),
                            {"address":addr},
                            {"address":addr, "account":"", "amount":0, "confirmations":0, "txids":[]})
 
@@ -126,7 +100,7 @@ class ReceivedByTest(BitcoinTestFramework):
         self.sync_all()
 
         # listreceivedbyaccount should return received_by_account_json because of 0 confirmations
-        check_array_result(self.nodes[1].listreceivedbyaccount(),
+        assert_array_result(self.nodes[1].listreceivedbyaccount(),
                            {"account":account},
                            received_by_account_json)
 
@@ -138,7 +112,7 @@ class ReceivedByTest(BitcoinTestFramework):
         self.nodes[1].generate(10)
         self.sync_all()
         # listreceivedbyaccount should return updated account balance
-        check_array_result(self.nodes[1].listreceivedbyaccount(),
+        assert_array_result(self.nodes[1].listreceivedbyaccount(),
                            {"account":account},
                            {"account":received_by_account_json["account"], "amount":(received_by_account_json["amount"] + Decimal("0.1"))})
 
diff --git a/qa/rpc-tests/replace-by-fee.py b/qa/rpc-tests/replace-by-fee.py
index ba1956853..4c8ef6de2 100755
--- a/qa/rpc-tests/replace-by-fee.py
+++ b/qa/rpc-tests/replace-by-fee.py
@@ -11,16 +11,11 @@ from test_framework.test_framework import BitcoinTestFramework
 from test_framework.util import *
 from test_framework.script import *
 from test_framework.mininode import *
-import binascii
 
-COIN = 100000000
 MAX_REPLACEMENT_LIMIT = 100
 
-def satoshi_round(amount):
-    return Decimal(amount).quantize(Decimal('0.00000001'), rounding=ROUND_DOWN)
-
 def txToHex(tx):
-    return binascii.hexlify(tx.serialize()).decode('utf-8')
+    return bytes_to_hex_str(tx.serialize())
 
 def make_utxo(node, amount, confirmed=True, scriptPubKey=CScript([1])):
     """Create a txout with a given amount and scriptPubKey
@@ -54,9 +49,7 @@ def make_utxo(node, amount, confirmed=True, scriptPubKey=CScript([1])):
     tx2.vout = [CTxOut(amount, scriptPubKey)]
     tx2.rehash()
 
-    binascii.hexlify(tx2.serialize()).decode('utf-8')
-
-    signed_tx = node.signrawtransaction(binascii.hexlify(tx2.serialize()).decode('utf-8'))
+    signed_tx = node.signrawtransaction(txToHex(tx2))
 
     txid = node.sendrawtransaction(signed_tx['hex'], True)
 
@@ -120,7 +113,7 @@ class ReplaceByFeeTest(BitcoinTestFramework):
 
     def test_simple_doublespend(self):
         """Simple doublespend"""
-        tx0_outpoint = make_utxo(self.nodes[0], 1.1*COIN)
+        tx0_outpoint = make_utxo(self.nodes[0], int(1.1*COIN))
 
         tx1a = CTransaction()
         tx1a.vin = [CTxIn(tx0_outpoint, nSequence=0)]
@@ -144,7 +137,7 @@ class ReplaceByFeeTest(BitcoinTestFramework):
         # Extra 0.1 BTC fee
         tx1b = CTransaction()
         tx1b.vin = [CTxIn(tx0_outpoint, nSequence=0)]
-        tx1b.vout = [CTxOut(0.9*COIN, CScript([b'b']))]
+        tx1b.vout = [CTxOut(int(0.9*COIN), CScript([b'b']))]
         tx1b_hex = txToHex(tx1b)
         tx1b_txid = self.nodes[0].sendrawtransaction(tx1b_hex, True)
 
@@ -236,7 +229,7 @@ class ReplaceByFeeTest(BitcoinTestFramework):
                                   _total_txs=_total_txs):
                     yield x
 
-        fee = 0.0001*COIN
+        fee = int(0.0001*COIN)
         n = MAX_REPLACEMENT_LIMIT
         tree_txs = list(branch(tx0_outpoint, initial_nValue, n, fee=fee))
         assert_equal(len(tree_txs), n)
@@ -269,7 +262,7 @@ class ReplaceByFeeTest(BitcoinTestFramework):
         # Try again, but with more total transactions than the "max txs
         # double-spent at once" anti-DoS limit.
         for n in (MAX_REPLACEMENT_LIMIT+1, MAX_REPLACEMENT_LIMIT*2):
-            fee = 0.0001*COIN
+            fee = int(0.0001*COIN)
             tx0_outpoint = make_utxo(self.nodes[0], initial_nValue)
             tree_txs = list(branch(tx0_outpoint, initial_nValue, n, fee=fee))
             assert_equal(len(tree_txs), n)
@@ -292,7 +285,7 @@ class ReplaceByFeeTest(BitcoinTestFramework):
 
     def test_replacement_feeperkb(self):
         """Replacement requires fee-per-KB to be higher"""
-        tx0_outpoint = make_utxo(self.nodes[0], 1.1*COIN)
+        tx0_outpoint = make_utxo(self.nodes[0], int(1.1*COIN))
 
         tx1a = CTransaction()
         tx1a.vin = [CTxIn(tx0_outpoint, nSequence=0)]
@@ -304,7 +297,7 @@ class ReplaceByFeeTest(BitcoinTestFramework):
         # rejected.
         tx1b = CTransaction()
         tx1b.vin = [CTxIn(tx0_outpoint, nSequence=0)]
-        tx1b.vout = [CTxOut(0.001*COIN, CScript([b'a'*999000]))]
+        tx1b.vout = [CTxOut(int(0.001*COIN), CScript([b'a'*999000]))]
         tx1b_hex = txToHex(tx1b)
 
         try:
@@ -316,12 +309,12 @@ class ReplaceByFeeTest(BitcoinTestFramework):
 
     def test_spends_of_conflicting_outputs(self):
         """Replacements that spend conflicting tx outputs are rejected"""
-        utxo1 = make_utxo(self.nodes[0], 1.2*COIN)
-        utxo2 = make_utxo(self.nodes[0], 3.0*COIN)
+        utxo1 = make_utxo(self.nodes[0], int(1.2*COIN))
+        utxo2 = make_utxo(self.nodes[0], 3*COIN)
 
         tx1a = CTransaction()
         tx1a.vin = [CTxIn(utxo1, nSequence=0)]
-        tx1a.vout = [CTxOut(1.1*COIN, CScript([b'a']))]
+        tx1a.vout = [CTxOut(int(1.1*COIN), CScript([b'a']))]
         tx1a_hex = txToHex(tx1a)
         tx1a_txid = self.nodes[0].sendrawtransaction(tx1a_hex, True)
 
@@ -344,7 +337,7 @@ class ReplaceByFeeTest(BitcoinTestFramework):
         # Spend tx1a's output to test the indirect case.
         tx1b = CTransaction()
         tx1b.vin = [CTxIn(COutPoint(tx1a_txid, 0), nSequence=0)]
-        tx1b.vout = [CTxOut(1.0*COIN, CScript([b'a']))]
+        tx1b.vout = [CTxOut(1*COIN, CScript([b'a']))]
         tx1b_hex = txToHex(tx1b)
         tx1b_txid = self.nodes[0].sendrawtransaction(tx1b_hex, True)
         tx1b_txid = int(tx1b_txid, 16)
@@ -364,12 +357,12 @@ class ReplaceByFeeTest(BitcoinTestFramework):
 
     def test_new_unconfirmed_inputs(self):
         """Replacements that add new unconfirmed inputs are rejected"""
-        confirmed_utxo = make_utxo(self.nodes[0], 1.1*COIN)
-        unconfirmed_utxo = make_utxo(self.nodes[0], 0.1*COIN, False)
+        confirmed_utxo = make_utxo(self.nodes[0], int(1.1*COIN))
+        unconfirmed_utxo = make_utxo(self.nodes[0], int(0.1*COIN), False)
 
         tx1 = CTransaction()
         tx1.vin = [CTxIn(confirmed_utxo)]
-        tx1.vout = [CTxOut(1.0*COIN, CScript([b'a']))]
+        tx1.vout = [CTxOut(1*COIN, CScript([b'a']))]
         tx1_hex = txToHex(tx1)
         tx1_txid = self.nodes[0].sendrawtransaction(tx1_hex, True)
 
@@ -393,7 +386,7 @@ class ReplaceByFeeTest(BitcoinTestFramework):
         # Start by creating a single transaction with many outputs
         initial_nValue = 10*COIN
         utxo = make_utxo(self.nodes[0], initial_nValue)
-        fee = 0.0001*COIN
+        fee = int(0.0001*COIN)
         split_value = int((initial_nValue-fee)/(MAX_REPLACEMENT_LIMIT+1))
         actual_fee = initial_nValue - split_value*(MAX_REPLACEMENT_LIMIT+1)
 
@@ -446,7 +439,7 @@ class ReplaceByFeeTest(BitcoinTestFramework):
 
     def test_opt_in(self):
         """ Replacing should only work if orig tx opted in """
-        tx0_outpoint = make_utxo(self.nodes[0], 1.1*COIN)
+        tx0_outpoint = make_utxo(self.nodes[0], int(1.1*COIN))
 
         # Create a non-opting in transaction
         tx1a = CTransaction()
@@ -458,7 +451,7 @@ class ReplaceByFeeTest(BitcoinTestFramework):
         # Shouldn't be able to double-spend
         tx1b = CTransaction()
         tx1b.vin = [CTxIn(tx0_outpoint, nSequence=0)]
-        tx1b.vout = [CTxOut(0.9*COIN, CScript([b'b']))]
+        tx1b.vout = [CTxOut(int(0.9*COIN), CScript([b'b']))]
         tx1b_hex = txToHex(tx1b)
 
         try:
@@ -469,7 +462,7 @@ class ReplaceByFeeTest(BitcoinTestFramework):
             print tx1b_txid
             assert(False)
 
-        tx1_outpoint = make_utxo(self.nodes[0], 1.1*COIN)
+        tx1_outpoint = make_utxo(self.nodes[0], int(1.1*COIN))
 
         # Create a different non-opting in transaction
         tx2a = CTransaction()
@@ -481,7 +474,7 @@ class ReplaceByFeeTest(BitcoinTestFramework):
         # Still shouldn't be able to double-spend
         tx2b = CTransaction()
         tx2b.vin = [CTxIn(tx1_outpoint, nSequence=0)]
-        tx2b.vout = [CTxOut(0.9*COIN, CScript([b'b']))]
+        tx2b.vout = [CTxOut(int(0.9*COIN), CScript([b'b']))]
         tx2b_hex = txToHex(tx2b)
 
         try:
@@ -501,19 +494,19 @@ class ReplaceByFeeTest(BitcoinTestFramework):
         tx3a = CTransaction()
         tx3a.vin = [CTxIn(COutPoint(tx1a_txid, 0), nSequence=0xffffffff),
                     CTxIn(COutPoint(tx2a_txid, 0), nSequence=0xfffffffd)]
-        tx3a.vout = [CTxOut(0.9*COIN, CScript([b'c'])), CTxOut(0.9*COIN, CScript([b'd']))]
+        tx3a.vout = [CTxOut(int(0.9*COIN), CScript([b'c'])), CTxOut(int(0.9*COIN), CScript([b'd']))]
         tx3a_hex = txToHex(tx3a)
 
         self.nodes[0].sendrawtransaction(tx3a_hex, True)
 
         tx3b = CTransaction()
         tx3b.vin = [CTxIn(COutPoint(tx1a_txid, 0), nSequence=0)]
-        tx3b.vout = [CTxOut(0.5*COIN, CScript([b'e']))]
+        tx3b.vout = [CTxOut(int(0.5*COIN), CScript([b'e']))]
         tx3b_hex = txToHex(tx3b)
 
         tx3c = CTransaction()
         tx3c.vin = [CTxIn(COutPoint(tx2a_txid, 0), nSequence=0)]
-        tx3c.vout = [CTxOut(0.5*COIN, CScript([b'f']))]
+        tx3c.vout = [CTxOut(int(0.5*COIN), CScript([b'f']))]
         tx3c_hex = txToHex(tx3c)
 
         self.nodes[0].sendrawtransaction(tx3b_hex, True)
@@ -526,7 +519,7 @@ class ReplaceByFeeTest(BitcoinTestFramework):
         # correctly used by replacement logic
 
         # 1. Check that feeperkb uses modified fees
-        tx0_outpoint = make_utxo(self.nodes[0], 1.1*COIN)
+        tx0_outpoint = make_utxo(self.nodes[0], int(1.1*COIN))
 
         tx1a = CTransaction()
         tx1a.vin = [CTxIn(tx0_outpoint, nSequence=0)]
@@ -537,7 +530,7 @@ class ReplaceByFeeTest(BitcoinTestFramework):
         # Higher fee, but the actual fee per KB is much lower.
         tx1b = CTransaction()
         tx1b.vin = [CTxIn(tx0_outpoint, nSequence=0)]
-        tx1b.vout = [CTxOut(0.001*COIN, CScript([b'a'*740000]))]
+        tx1b.vout = [CTxOut(int(0.001*COIN), CScript([b'a'*740000]))]
         tx1b_hex = txToHex(tx1b)
 
         # Verify tx1b cannot replace tx1a.
@@ -557,7 +550,7 @@ class ReplaceByFeeTest(BitcoinTestFramework):
         assert(tx1b_txid in self.nodes[0].getrawmempool())
 
         # 2. Check that absolute fee checks use modified fee.
-        tx1_outpoint = make_utxo(self.nodes[0], 1.1*COIN)
+        tx1_outpoint = make_utxo(self.nodes[0], int(1.1*COIN))
 
         tx2a = CTransaction()
         tx2a.vin = [CTxIn(tx1_outpoint, nSequence=0)]
@@ -568,7 +561,7 @@ class ReplaceByFeeTest(BitcoinTestFramework):
         # Lower fee, but we'll prioritise it
         tx2b = CTransaction()
         tx2b.vin = [CTxIn(tx1_outpoint, nSequence=0)]
-        tx2b.vout = [CTxOut(1.01*COIN, CScript([b'a']))]
+        tx2b.vout = [CTxOut(int(1.01*COIN), CScript([b'a']))]
         tx2b.rehash()
         tx2b_hex = txToHex(tx2b)
 
diff --git a/qa/rpc-tests/rest.py b/qa/rpc-tests/rest.py
index 8c8353650..359f9239f 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
@@ -38,7 +39,7 @@ def http_get_call(host, port, path, response_object = 0):
     if response_object:
         return conn.getresponse()
 
-    return conn.getresponse().read()
+    return conn.getresponse().read().decode('utf-8')
 
 #allows simple http post calls with a request body
 def http_post_call(host, port, path, requestdata = '', response_object = 0):
@@ -140,13 +141,13 @@ class RESTTest (BitcoinTestFramework):
         bb_hash = self.nodes[0].getbestblockhash()
 
         binaryRequest = b'\x01\x02'
-        binaryRequest += binascii.unhexlify(txid)
+        binaryRequest += hex_str_to_bytes(txid)
         binaryRequest += pack("i", n)
-        binaryRequest += binascii.unhexlify(vintx)
+        binaryRequest += hex_str_to_bytes(vintx)
         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_codec")[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_codec")[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')
@@ -251,7 +252,7 @@ class RESTTest (BitcoinTestFramework):
         # compare with json block header
         response_header_json = http_get_call(url.hostname, url.port, '/rest/headers/1/'+bb_hash+self.FORMAT_SEPARATOR+"json", True)
         assert_equal(response_header_json.status, 200)
-        response_header_json_str = response_header_json.read()
+        response_header_json_str = response_header_json.read().decode('utf-8')
         json_obj = json.loads(response_header_json_str, parse_float=Decimal)
         assert_equal(len(json_obj), 1) #ensure that there is one header in the json response
         assert_equal(json_obj[0]['hash'], bb_hash) #request/response hash should be the same
@@ -275,7 +276,7 @@ class RESTTest (BitcoinTestFramework):
         self.sync_all()
         response_header_json = http_get_call(url.hostname, url.port, '/rest/headers/5/'+bb_hash+self.FORMAT_SEPARATOR+"json", True)
         assert_equal(response_header_json.status, 200)
-        response_header_json_str = response_header_json.read()
+        response_header_json_str = response_header_json.read().decode('utf-8')
         json_obj = json.loads(response_header_json_str)
         assert_equal(len(json_obj), 5) #now we should have 5 header objects
 
@@ -291,7 +292,6 @@ class RESTTest (BitcoinTestFramework):
         assert_greater_than(int(response.getheader('content-length')), 10)
 
 
-
         # check block tx details
         # let's make 3 tx and mine them on node 1
         txs = []
diff --git a/qa/rpc-tests/smartfees.py b/qa/rpc-tests/smartfees.py
index b209ae0c1..2c064ad8a 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)"
@@ -219,7 +219,7 @@ class EstimateFeeTest(BitcoinTestFramework):
                 from_index = random.randint(1,2)
                 (txhex, fee) = small_txpuzzle_randfee(self.nodes[from_index], self.confutxo,
                                                       self.memutxo, Decimal("0.005"), min_fee, min_fee)
-                tx_kbytes = (len(txhex)/2)/1000.0
+                tx_kbytes = (len(txhex) // 2) / 1000.0
                 self.fees_per_kb.append(float(fee)/tx_kbytes)
             sync_mempools(self.nodes[0:3],.1)
             mined = mining_node.getblock(mining_node.generate(1)[0],True)["tx"]
diff --git a/qa/rpc-tests/test_framework/blockstore.py b/qa/rpc-tests/test_framework/blockstore.py
index b9775b477..73d9ffbb2 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 88f553a7f..f8861c627 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):
@@ -29,7 +29,7 @@ def serialize_script_num(value):
     neg = value < 0
     absvalue = -value if neg else value
     while (absvalue):
-        r.append(chr(absvalue & 0xff))
+        r.append(int(absvalue & 0xff))
         absvalue >>= 8
     if r[-1] & 0x80:
         r.append(0x80 if neg else 0)
@@ -45,7 +45,7 @@ def create_coinbase(height, pubkey = None):
     coinbase.vin.append(CTxIn(COutPoint(0, 0xffffffff), 
                 ser_string(serialize_script_num(height)), 0xffffffff))
     coinbaseoutput = CTxOut()
-    coinbaseoutput.nValue = 50*100000000
+    coinbaseoutput.nValue = 50 * COIN
     halvings = int(height/150) # regtest
     coinbaseoutput.nValue >>= halvings
     if (pubkey != None):
@@ -62,6 +62,6 @@ def create_transaction(prevtx, n, sig, value):
     tx = CTransaction()
     assert(n < len(prevtx.vout))
     tx.vin.append(CTxIn(COutPoint(prevtx.sha256, n), sig, 0xffffffff))
-    tx.vout.append(CTxOut(value, ""))
+    tx.vout.append(CTxOut(value, b""))
     tx.calc_sha256()
     return tx
diff --git a/qa/rpc-tests/test_framework/comptool.py b/qa/rpc-tests/test_framework/comptool.py
index 544321705..74aabdd01 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
@@ -45,7 +45,7 @@ class RejectResult(object):
     '''
     Outcome that expects rejection of a transaction or block.
     '''
-    def __init__(self, code, reason=''):
+    def __init__(self, code, reason=b''):
         self.code = code
         self.reason = reason
     def match(self, other):
@@ -111,9 +111,9 @@ class TestNode(NodeConnCB):
             raise AssertionError("Got pong for unknown ping [%s]" % repr(message))
 
     def on_reject(self, conn, message):
-        if message.message == 'tx':
+        if message.message == b'tx':
             self.tx_reject_map[message.data] = RejectResult(message.code, message.reason)
-        if message.message == 'block':
+        if message.message == b'block':
             self.block_reject_map[message.data] = RejectResult(message.code, message.reason)
 
     def send_inv(self, obj):
diff --git a/qa/rpc-tests/test_framework/mininode.py b/qa/rpc-tests/test_framework/mininode.py
index 81bb439ce..3198620ca 100755
--- a/qa/rpc-tests/test_framework/mininode.py
+++ b/qa/rpc-tests/test_framework/mininode.py
@@ -20,11 +20,12 @@
 import struct
 import socket
 import asyncore
-import binascii
 import time
 import sys
 import random
-import cStringIO
+from binascii import hexlify, unhexlify
+from io import BytesIO
+from codecs import encode
 import hashlib
 from threading import RLock
 from threading import Thread
@@ -33,11 +34,13 @@ import copy
 
 BIP0031_VERSION = 60000
 MY_VERSION = 60001  # past bip-31 for ping/pong
-MY_SUBVERSION = "/python-mininode-tester:0.0.1/"
+MY_SUBVERSION = b"/python-mininode-tester:0.0.2/"
 
 MAX_INV_SZ = 50000
 MAX_BLOCK_SIZE = 1000000
 
+COIN = 100000000L # 1 btc in satoshis
+
 # Keep our own socket map for asyncore, so that we can track disconnects
 # ourselves (to workaround an issue with closing an asyncore socket when 
 # using select)
@@ -73,12 +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("<BH", 253, 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("<BI", 254, len(s)) + s
+    return struct.pack("<BQ", 255, len(s)) + s
 
 
 def deser_uint256(f):
@@ -128,15 +131,15 @@ def deser_vector(f, c):
 
 
 def ser_vector(l):
-    r = ""
+    r = b""
     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("<BH", 253, len(l))
     elif len(l) < 0x100000000L:
-        r = chr(254) + struct.pack("<I", len(l))
+        r = struct.pack("<BI", 254, len(l))
     else:
-        r = chr(255) + struct.pack("<Q", len(l))
+        r = struct.pack("<BQ", 255, len(l))
     for i in l:
         r += i.serialize()
     return r
@@ -158,15 +161,15 @@ def deser_uint256_vector(f):
 
 
 def ser_uint256_vector(l):
-    r = ""
+    r = b""
     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("<BH", 253, len(l))
     elif len(l) < 0x100000000L:
-        r = chr(254) + struct.pack("<I", len(l))
+        r = struct.pack("<BI", 254, len(l))
     else:
-        r = chr(255) + struct.pack("<Q", len(l))
+        r = struct.pack("<BQ", 255, len(l))
     for i in l:
         r += ser_uint256(i)
     return r
@@ -190,13 +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("<BH", 253, len(l))
     elif len(l) < 0x100000000L:
-        r = chr(254) + struct.pack("<I", len(l))
+        r = struct.pack("<BI", 254, len(l))
     else:
-        r = chr(255) + struct.pack("<Q", len(l))
+        r = struct.pack("<BQ", 255, len(l))
     for sv in l:
         r += ser_string(sv)
     return r
@@ -218,34 +221,34 @@ def deser_int_vector(f):
 
 
 def ser_int_vector(l):
-    r = ""
+    r = b""
     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("<BH", 253, len(l))
     elif len(l) < 0x100000000L:
-        r = chr(254) + struct.pack("<I", len(l))
+        r = struct.pack("<BI", 254, len(l))
     else:
-        r = chr(255) + struct.pack("<Q", len(l))
+        r = struct.pack("<BQ", 255, 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(unhexlify(hex_string.encode('ascii'))))
     return obj
 
 # Convert a binary-serializable object to hex (eg for submission via RPC)
 def ToHex(obj):
-    return binascii.hexlify(obj.serialize()).decode('utf-8')
+    return hexlify(obj.serialize()).decode('ascii')
 
 # Objects that map to bitcoind objects, which can be serialized/deserialized
 
 class CAddress(object):
     def __init__(self):
         self.nServices = 1
-        self.pchReserved = "\x00" * 10 + "\xff" * 2
+        self.pchReserved = b"\x00" * 10 + b"\xff" * 2
         self.ip = "0.0.0.0"
         self.port = 0
 
@@ -256,7 +259,7 @@ class CAddress(object):
         self.port = struct.unpack(">H", f.read(2))[0]
 
     def serialize(self):
-        r = ""
+        r = b""
         r += struct.pack("<Q", self.nServices)
         r += self.pchReserved
         r += socket.inet_aton(self.ip)
@@ -283,7 +286,7 @@ class CInv(object):
         self.hash = deser_uint256(f)
 
     def serialize(self):
-        r = ""
+        r = b""
         r += struct.pack("<i", self.type)
         r += ser_uint256(self.hash)
         return r
@@ -303,7 +306,7 @@ class CBlockLocator(object):
         self.vHave = deser_uint256_vector(f)
 
     def serialize(self):
-        r = ""
+        r = b""
         r += struct.pack("<i", self.nVersion)
         r += ser_uint256_vector(self.vHave)
         return r
@@ -323,7 +326,7 @@ class COutPoint(object):
         self.n = struct.unpack("<I", f.read(4))[0]
 
     def serialize(self):
-        r = ""
+        r = b""
         r += ser_uint256(self.hash)
         r += struct.pack("<I", self.n)
         return r
@@ -333,7 +336,7 @@ class COutPoint(object):
 
 
 class CTxIn(object):
-    def __init__(self, outpoint=None, scriptSig="", nSequence=0):
+    def __init__(self, outpoint=None, scriptSig=b"", nSequence=0):
         if outpoint is None:
             self.prevout = COutPoint()
         else:
@@ -348,7 +351,7 @@ class CTxIn(object):
         self.nSequence = struct.unpack("<I", f.read(4))[0]
 
     def serialize(self):
-        r = ""
+        r = b""
         r += self.prevout.serialize()
         r += ser_string(self.scriptSig)
         r += struct.pack("<I", self.nSequence)
@@ -356,12 +359,12 @@ class CTxIn(object):
 
     def __repr__(self):
         return "CTxIn(prevout=%s scriptSig=%s nSequence=%i)" \
-            % (repr(self.prevout), binascii.hexlify(self.scriptSig),
+            % (repr(self.prevout), hexlify(self.scriptSig),
                self.nSequence)
 
 
 class CTxOut(object):
-    def __init__(self, nValue=0, scriptPubKey=""):
+    def __init__(self, nValue=0, scriptPubKey=b""):
         self.nValue = nValue
         self.scriptPubKey = scriptPubKey
 
@@ -370,15 +373,15 @@ class CTxOut(object):
         self.scriptPubKey = deser_string(f)
 
     def serialize(self):
-        r = ""
+        r = b""
         r += struct.pack("<q", self.nValue)
         r += ser_string(self.scriptPubKey)
         return r
 
     def __repr__(self):
         return "CTxOut(nValue=%i.%08i scriptPubKey=%s)" \
-            % (self.nValue // 100000000, self.nValue % 100000000,
-               binascii.hexlify(self.scriptPubKey))
+            % (self.nValue // COIN, self.nValue % COIN,
+               hexlify(self.scriptPubKey))
 
 
 class CTransaction(object):
@@ -407,7 +410,7 @@ class CTransaction(object):
         self.hash = None
 
     def serialize(self):
-        r = ""
+        r = b""
         r += struct.pack("<i", self.nVersion)
         r += ser_vector(self.vin)
         r += ser_vector(self.vout)
@@ -421,12 +424,12 @@ 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_codec').decode('ascii')
 
     def is_valid(self):
         self.calc_sha256()
         for tout in self.vout:
-            if tout.nValue < 0 or tout.nValue > 21000000L * 100000000L:
+            if tout.nValue < 0 or tout.nValue > 21000000 * COIN:
                 return False
         return True
 
@@ -471,7 +474,7 @@ class CBlockHeader(object):
         self.hash = None
 
     def serialize(self):
-        r = ""
+        r = b""
         r += struct.pack("<i", self.nVersion)
         r += ser_uint256(self.hashPrevBlock)
         r += ser_uint256(self.hashMerkleRoot)
@@ -482,7 +485,7 @@ class CBlockHeader(object):
 
     def calc_sha256(self):
         if self.sha256 is None:
-            r = ""
+            r = b""
             r += struct.pack("<i", self.nVersion)
             r += ser_uint256(self.hashPrevBlock)
             r += ser_uint256(self.hashMerkleRoot)
@@ -490,7 +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_codec').decode('ascii')
 
     def rehash(self):
         self.sha256 = None
@@ -513,7 +516,7 @@ class CBlock(CBlockHeader):
         self.vtx = deser_vector(f, CTransaction)
 
     def serialize(self):
-        r = ""
+        r = b""
         r += super(CBlock, self).serialize()
         r += ser_vector(self.vtx)
         return r
@@ -568,9 +571,9 @@ class CUnsignedAlert(object):
         self.nMaxVer = 0
         self.setSubVer = []
         self.nPriority = 0
-        self.strComment = ""
-        self.strStatusBar = ""
-        self.strReserved = ""
+        self.strComment = b""
+        self.strStatusBar = b""
+        self.strReserved = b""
 
     def deserialize(self, f):
         self.nVersion = struct.unpack("<i", f.read(4))[0]
@@ -588,7 +591,7 @@ class CUnsignedAlert(object):
         self.strReserved = deser_string(f)
 
     def serialize(self):
-        r = ""
+        r = b""
         r += struct.pack("<i", self.nVersion)
         r += struct.pack("<q", self.nRelayUntil)
         r += struct.pack("<q", self.nExpiration)
@@ -613,8 +616,8 @@ class CUnsignedAlert(object):
 
 class CAlert(object):
     def __init__(self):
-        self.vchMsg = ""
-        self.vchSig = ""
+        self.vchMsg = b""
+        self.vchSig = b""
 
     def deserialize(self, f):
         self.vchMsg = deser_string(f)
@@ -633,12 +636,12 @@ class CAlert(object):
 
 # Objects that correspond to messages on the wire
 class msg_version(object):
-    command = "version"
+    command = b"version"
 
     def __init__(self):
         self.nVersion = MY_VERSION
         self.nServices = 1
-        self.nTime = time.time()
+        self.nTime = int(time.time())
         self.addrTo = CAddress()
         self.addrFrom = CAddress()
         self.nNonce = random.getrandbits(64)
@@ -669,7 +672,7 @@ class msg_version(object):
             self.nStartingHeight = None
 
     def serialize(self):
-        r = ""
+        r = b""
         r += struct.pack("<i", self.nVersion)
         r += struct.pack("<Q", self.nServices)
         r += struct.pack("<q", self.nTime)
@@ -688,7 +691,7 @@ class msg_version(object):
 
 
 class msg_verack(object):
-    command = "verack"
+    command = b"verack"
 
     def __init__(self):
         pass
@@ -697,14 +700,14 @@ class msg_verack(object):
         pass
 
     def serialize(self):
-        return ""
+        return b""
 
     def __repr__(self):
         return "msg_verack()"
 
 
 class msg_addr(object):
-    command = "addr"
+    command = b"addr"
 
     def __init__(self):
         self.addrs = []
@@ -720,7 +723,7 @@ class msg_addr(object):
 
 
 class msg_alert(object):
-    command = "alert"
+    command = b"alert"
 
     def __init__(self):
         self.alert = CAlert()
@@ -730,7 +733,7 @@ class msg_alert(object):
         self.alert.deserialize(f)
 
     def serialize(self):
-        r = ""
+        r = b""
         r += self.alert.serialize()
         return r
 
@@ -739,7 +742,7 @@ class msg_alert(object):
 
 
 class msg_inv(object):
-    command = "inv"
+    command = b"inv"
 
     def __init__(self, inv=None):
         if inv is None:
@@ -758,7 +761,7 @@ class msg_inv(object):
 
 
 class msg_getdata(object):
-    command = "getdata"
+    command = b"getdata"
 
     def __init__(self, inv=None):
         self.inv = inv if inv != None else []
@@ -774,7 +777,7 @@ class msg_getdata(object):
 
 
 class msg_getblocks(object):
-    command = "getblocks"
+    command = b"getblocks"
 
     def __init__(self):
         self.locator = CBlockLocator()
@@ -786,7 +789,7 @@ class msg_getblocks(object):
         self.hashstop = deser_uint256(f)
 
     def serialize(self):
-        r = ""
+        r = b""
         r += self.locator.serialize()
         r += ser_uint256(self.hashstop)
         return r
@@ -797,7 +800,7 @@ class msg_getblocks(object):
 
 
 class msg_tx(object):
-    command = "tx"
+    command = b"tx"
 
     def __init__(self, tx=CTransaction()):
         self.tx = tx
@@ -813,7 +816,7 @@ class msg_tx(object):
 
 
 class msg_block(object):
-    command = "block"
+    command = b"block"
 
     def __init__(self, block=None):
         if block is None:
@@ -832,7 +835,7 @@ class msg_block(object):
 
 
 class msg_getaddr(object):
-    command = "getaddr"
+    command = b"getaddr"
 
     def __init__(self):
         pass
@@ -841,14 +844,14 @@ class msg_getaddr(object):
         pass
 
     def serialize(self):
-        return ""
+        return b""
 
     def __repr__(self):
         return "msg_getaddr()"
 
 
 class msg_ping_prebip31(object):
-    command = "ping"
+    command = b"ping"
 
     def __init__(self):
         pass
@@ -857,14 +860,14 @@ class msg_ping_prebip31(object):
         pass
 
     def serialize(self):
-        return ""
+        return b""
 
     def __repr__(self):
         return "msg_ping() (pre-bip31)"
 
 
 class msg_ping(object):
-    command = "ping"
+    command = b"ping"
 
     def __init__(self, nonce=0L):
         self.nonce = nonce
@@ -873,7 +876,7 @@ class msg_ping(object):
         self.nonce = struct.unpack("<Q", f.read(8))[0]
 
     def serialize(self):
-        r = ""
+        r = b""
         r += struct.pack("<Q", self.nonce)
         return r
 
@@ -882,16 +885,16 @@ class msg_ping(object):
 
 
 class msg_pong(object):
-    command = "pong"
+    command = b"pong"
 
-    def __init__(self, nonce=0L):
+    def __init__(self, nonce=0):
         self.nonce = nonce
 
     def deserialize(self, f):
         self.nonce = struct.unpack("<Q", f.read(8))[0]
 
     def serialize(self):
-        r = ""
+        r = b""
         r += struct.pack("<Q", self.nonce)
         return r
 
@@ -900,7 +903,7 @@ class msg_pong(object):
 
 
 class msg_mempool(object):
-    command = "mempool"
+    command = b"mempool"
 
     def __init__(self):
         pass
@@ -909,13 +912,13 @@ class msg_mempool(object):
         pass
 
     def serialize(self):
-        return ""
+        return b""
 
     def __repr__(self):
         return "msg_mempool()"
 
 class msg_sendheaders(object):
-    command = "sendheaders"
+    command = b"sendheaders"
 
     def __init__(self):
         pass
@@ -924,7 +927,7 @@ class msg_sendheaders(object):
         pass
 
     def serialize(self):
-        return ""
+        return b""
 
     def __repr__(self):
         return "msg_sendheaders()"
@@ -934,7 +937,7 @@ class msg_sendheaders(object):
 # vector of hashes
 # hash_stop (hash of last desired block header, 0 to get as many as possible)
 class msg_getheaders(object):
-    command = "getheaders"
+    command = b"getheaders"
 
     def __init__(self):
         self.locator = CBlockLocator()
@@ -946,7 +949,7 @@ class msg_getheaders(object):
         self.hashstop = deser_uint256(f)
 
     def serialize(self):
-        r = ""
+        r = b""
         r += self.locator.serialize()
         r += ser_uint256(self.hashstop)
         return r
@@ -959,7 +962,7 @@ class msg_getheaders(object):
 # headers message has
 # <count> <vector of block headers>
 class msg_headers(object):
-    command = "headers"
+    command = b"headers"
 
     def __init__(self):
         self.headers = []
@@ -979,11 +982,11 @@ class msg_headers(object):
 
 
 class msg_reject(object):
-    command = "reject"
+    command = b"reject"
 
     def __init__(self):
-        self.message = ""
-        self.code = ""
+        self.message = b""
+        self.code = 0
         self.reason = ""
         self.data = 0L
 
@@ -1006,7 +1009,6 @@ class msg_reject(object):
         return "msg_reject: %s %d %s [%064x]" \
             % (self.message, self.code, self.reason, self.data)
 
-
 # This is what a callback should look like for NodeConn
 # Reimplement the on_* functions to provide handling for events
 class NodeConnCB(object):
@@ -1088,27 +1090,27 @@ class NodeConnCB(object):
 # This class provides an interface for a p2p connection to a specified node
 class NodeConn(asyncore.dispatcher):
     messagemap = {
-        "version": msg_version,
-        "verack": msg_verack,
-        "addr": msg_addr,
-        "alert": msg_alert,
-        "inv": msg_inv,
-        "getdata": msg_getdata,
-        "getblocks": msg_getblocks,
-        "tx": msg_tx,
-        "block": msg_block,
-        "getaddr": msg_getaddr,
-        "ping": msg_ping,
-        "pong": msg_pong,
-        "headers": msg_headers,
-        "getheaders": msg_getheaders,
-        "reject": msg_reject,
-        "mempool": msg_mempool
+        b"version": msg_version,
+        b"verack": msg_verack,
+        b"addr": msg_addr,
+        b"alert": msg_alert,
+        b"inv": msg_inv,
+        b"getdata": msg_getdata,
+        b"getblocks": msg_getblocks,
+        b"tx": msg_tx,
+        b"block": msg_block,
+        b"getaddr": msg_getaddr,
+        b"ping": msg_ping,
+        b"pong": msg_pong,
+        b"headers": msg_headers,
+        b"getheaders": msg_getheaders,
+        b"reject": msg_reject,
+        b"mempool": msg_mempool,
     }
     MAGIC_BYTES = {
-        "mainnet": "\xf9\xbe\xb4\xd9",   # mainnet
-        "testnet3": "\x0b\x11\x09\x07",  # testnet3
-        "regtest": "\xfa\xbf\xb5\xda"    # regtest
+        "mainnet": b"\xf9\xbe\xb4\xd9",   # mainnet
+        "testnet3": b"\x0b\x11\x09\x07",  # testnet3
+        "regtest": b"\xfa\xbf\xb5\xda"    # regtest
     }
 
     def __init__(self, dstaddr, dstport, rpc, callback, net="regtest", services=1):
@@ -1117,8 +1119,8 @@ class NodeConn(asyncore.dispatcher):
         self.dstaddr = dstaddr
         self.dstport = dstport
         self.create_socket(socket.AF_INET, socket.SOCK_STREAM)
-        self.sendbuf = ""
-        self.recvbuf = ""
+        self.sendbuf = b""
+        self.recvbuf = b""
         self.ver_send = 209
         self.ver_recv = 209
         self.last_sent = 0
@@ -1155,8 +1157,8 @@ class NodeConn(asyncore.dispatcher):
         self.show_debug_msg("MiniNode: Closing Connection to %s:%d... "
                             % (self.dstaddr, self.dstport))
         self.state = "closed"
-        self.recvbuf = ""
-        self.sendbuf = ""
+        self.recvbuf = b""
+        self.sendbuf = b""
         try:
             self.close()
         except:
@@ -1190,43 +1192,46 @@ class NodeConn(asyncore.dispatcher):
             self.sendbuf = self.sendbuf[sent:]
 
     def got_data(self):
-        while True:
-            if len(self.recvbuf) < 4:
-                return
-            if self.recvbuf[:4] != self.MAGIC_BYTES[self.network]:
-                raise ValueError("got garbage %s" % repr(self.recvbuf))
-            if self.ver_recv < 209:
-                if len(self.recvbuf) < 4 + 12 + 4:
+        try:
+            while True:
+                if len(self.recvbuf) < 4:
                     return
-                command = self.recvbuf[4:4+12].split("\x00", 1)[0]
-                msglen = struct.unpack("<i", self.recvbuf[4+12:4+12+4])[0]
-                checksum = None
-                if len(self.recvbuf) < 4 + 12 + 4 + msglen:
-                    return
-                msg = self.recvbuf[4+12+4:4+12+4+msglen]
-                self.recvbuf = self.recvbuf[4+12+4+msglen:]
-            else:
-                if len(self.recvbuf) < 4 + 12 + 4 + 4:
-                    return
-                command = self.recvbuf[4:4+12].split("\x00", 1)[0]
-                msglen = struct.unpack("<i", self.recvbuf[4+12:4+12+4])[0]
-                checksum = self.recvbuf[4+12+4:4+12+4+4]
-                if len(self.recvbuf) < 4 + 12 + 4 + 4 + msglen:
-                    return
-                msg = self.recvbuf[4+12+4+4:4+12+4+4+msglen]
-                th = sha256(msg)
-                h = sha256(th)
-                if checksum != h[:4]:
-                    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)
-                t = self.messagemap[command]()
-                t.deserialize(f)
-                self.got_message(t)
-            else:
-                self.show_debug_msg("Unknown command: '" + command + "' " +
-                                    repr(msg))
+                if self.recvbuf[:4] != self.MAGIC_BYTES[self.network]:
+                    raise ValueError("got garbage %s" % repr(self.recvbuf))
+                if self.ver_recv < 209:
+                    if len(self.recvbuf) < 4 + 12 + 4:
+                        return
+                    command = self.recvbuf[4:4+12].split(b"\x00", 1)[0]
+                    msglen = struct.unpack("<i", self.recvbuf[4+12:4+12+4])[0]
+                    checksum = None
+                    if len(self.recvbuf) < 4 + 12 + 4 + msglen:
+                        return
+                    msg = self.recvbuf[4+12+4:4+12+4+msglen]
+                    self.recvbuf = self.recvbuf[4+12+4+msglen:]
+                else:
+                    if len(self.recvbuf) < 4 + 12 + 4 + 4:
+                        return
+                    command = self.recvbuf[4:4+12].split(b"\x00", 1)[0]
+                    msglen = struct.unpack("<i", self.recvbuf[4+12:4+12+4])[0]
+                    checksum = self.recvbuf[4+12+4:4+12+4+4]
+                    if len(self.recvbuf) < 4 + 12 + 4 + 4 + msglen:
+                        return
+                    msg = self.recvbuf[4+12+4+4:4+12+4+4+msglen]
+                    th = sha256(msg)
+                    h = sha256(th)
+                    if checksum != h[:4]:
+                        raise ValueError("got bad checksum " + repr(self.recvbuf))
+                    self.recvbuf = self.recvbuf[4+12+4+4+msglen:]
+                if command in self.messagemap:
+                    f = BytesIO(msg)
+                    t = self.messagemap[command]()
+                    t.deserialize(f)
+                    self.got_message(t)
+                else:
+                    self.show_debug_msg("Unknown command: '" + command + "' " +
+                                        repr(msg))
+        except Exception as e:
+            print 'got_data:', repr(e)
 
     def send_message(self, message, pushbuf=False):
         if self.state != "connected" and not pushbuf:
@@ -1236,7 +1241,7 @@ class NodeConn(asyncore.dispatcher):
         data = message.serialize()
         tmsg = self.MAGIC_BYTES[self.network]
         tmsg += command
-        tmsg += "\x00" * (12 - len(command))
+        tmsg += b"\x00" * (12 - len(command))
         tmsg += struct.pack("<I", len(data))
         if self.ver_send >= 209:
             th = sha256(data)
@@ -1248,11 +1253,11 @@ class NodeConn(asyncore.dispatcher):
             self.last_sent = time.time()
 
     def got_message(self, message):
-        if message.command == "version":
+        if message.command == b"version":
             if message.nVersion <= BIP0031_VERSION:
-                self.messagemap['ping'] = msg_ping_prebip31
+                self.messagemap[b'ping'] = msg_ping_prebip31
         if self.last_sent + 30 * 60 < time.time():
-            self.send_message(self.messagemap['ping']())
+            self.send_message(self.messagemap[b'ping']())
         self.show_debug_msg("Recv %s" % repr(message))
         self.cb.deliver(self, message)
 
diff --git a/qa/rpc-tests/test_framework/netutil.py b/qa/rpc-tests/test_framework/netutil.py
index 50daa8793..c76de9342 100644
--- a/qa/rpc-tests/test_framework/netutil.py
+++ b/qa/rpc-tests/test_framework/netutil.py
@@ -4,13 +4,14 @@
 # file COPYING or http://www.opensource.org/licenses/mit-license.php.
 
 # Linux network utilities
+
 import sys
 import socket
 import fcntl
 import struct
 import array
 import os
-import binascii
+from binascii import unhexlify, hexlify
 
 # Roughly based on http://voorloopnul.com/blog/a-python-netstat-in-less-than-100-lines-of-code/ by Ricardo Pascal
 STATE_ESTABLISHED = '01'
@@ -43,9 +44,9 @@ def _remove_empty(array):
 def _convert_ip_port(array):
     host,port = array.split(':')
     # convert host from mangled-per-four-bytes form as used by kernel
-    host = binascii.unhexlify(host)
+    host = unhexlify(host)
     host_out = ''
-    for x in range(0, len(host)/4):
+    for x in range(0, len(host) // 4):
         (val,) = struct.unpack('=I', host[x*4:(x+1)*4])
         host_out += '%08x' % val
 
@@ -94,7 +95,7 @@ def all_interfaces():
     max_possible = 8 # initial value
     while True:
         bytes = max_possible * struct_size
-        names = array.array('B', '\0' * bytes)
+        names = array.array('B', b'\0' * bytes)
         outbytes = struct.unpack('iL', fcntl.ioctl(
             s.fileno(),
             0x8912,  # SIOCGIFCONF
@@ -105,7 +106,7 @@ def all_interfaces():
         else:
             break
     namestr = names.tostring()
-    return [(namestr[i:i+16].split('\0', 1)[0],
+    return [(namestr[i:i+16].split(b'\0', 1)[0],
              socket.inet_ntoa(namestr[i+20:i+24]))
             for i in range(0, outbytes, struct_size)]
 
@@ -136,4 +137,4 @@ def addr_to_hex(addr):
         addr = sub[0] + ([0] * nullbytes) + sub[1]
     else:
         raise ValueError('Could not parse address %s' % addr)
-    return binascii.hexlify(bytearray(addr))
+    return hexlify(bytearray(addr)).decode('ascii')
diff --git a/qa/rpc-tests/test_framework/script.py b/qa/rpc-tests/test_framework/script.py
index bf5e25fb2..5fb5758f8 100644
--- a/qa/rpc-tests/test_framework/script.py
+++ b/qa/rpc-tests/test_framework/script.py
@@ -629,7 +629,7 @@ class CScriptNum(object):
         neg = obj.value < 0
         absvalue = -obj.value if neg else obj.value
         while (absvalue):
-            r.append(chr(absvalue & 0xff))
+            r.append(absvalue & 0xff)
             absvalue >>= 8
         if r[-1] & 0x80:
             r.append(0x80 if neg else 0)
@@ -777,7 +777,7 @@ class CScript(bytes):
         # need to change
         def _repr(o):
             if isinstance(o, bytes):
-                return "x('%s')" % hexlify(o).decode('utf8')
+                return b"x('%s')" % hexlify(o).decode('ascii')
             else:
                 return repr(o)
 
diff --git a/qa/rpc-tests/test_framework/socks5.py b/qa/rpc-tests/test_framework/socks5.py
index 1dbfb98d5..f725d9770 100644
--- a/qa/rpc-tests/test_framework/socks5.py
+++ b/qa/rpc-tests/test_framework/socks5.py
@@ -102,7 +102,7 @@ class Socks5Connection(object):
                 addr = recvall(self.conn, 4)
             elif atyp == AddressType.DOMAINNAME:
                 n = recvall(self.conn, 1)[0]
-                addr = str(recvall(self.conn, n))
+                addr = recvall(self.conn, n)
             elif atyp == AddressType.IPV6:
                 addr = recvall(self.conn, 16)
             else:
@@ -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 584f318d0..19ee47260 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/test_framework/util.py b/qa/rpc-tests/test_framework/util.py
index c71ca0d9f..3d08fc7d7 100644
--- a/qa/rpc-tests/test_framework/util.py
+++ b/qa/rpc-tests/test_framework/util.py
@@ -1,6 +1,8 @@
 # Copyright (c) 2014-2015 The Bitcoin Core developers
 # Distributed under the MIT software license, see the accompanying
 # file COPYING or http://www.opensource.org/licenses/mit-license.php.
+
+
 #
 # Helpful routines for regression testing
 #
@@ -9,6 +11,8 @@
 import os
 import sys
 
+from binascii import hexlify, unhexlify
+from base64 import b64encode
 from decimal import Decimal, ROUND_DOWN
 import json
 import random
@@ -70,6 +74,15 @@ def check_json_precision():
 def count_bytes(hex_string):
     return len(bytearray.fromhex(hex_string))
 
+def bytes_to_hex_str(byte_str):
+    return hexlify(byte_str).decode('ascii')
+
+def hex_str_to_bytes(hex_str):
+    return unhexlify(hex_str.encode('ascii'))
+
+def str_to_b64str(string):
+    return b64encode(string.encode('utf-8')).decode('ascii')
+
 def sync_blocks(rpc_connections, wait=1):
     """
     Wait until everybody has the same block count
@@ -424,9 +437,40 @@ def assert_is_hash_string(string, length=64):
         raise AssertionError(
             "String %r contains invalid characters for a hash." % string)
 
-def satoshi_round(amount):
-    return  Decimal(amount).quantize(Decimal('0.00000001'), rounding=ROUND_DOWN)
+def assert_array_result(object_array, to_match, expected, should_not_find = False):
+    """
+        Pass in array of JSON objects, a dictionary with key/value pairs
+        to match against, and another dictionary with expected key/value
+        pairs.
+        If the should_not_find flag is true, to_match should not be found
+        in object_array
+        """
+    if should_not_find == True:
+        expected = { }
+    num_matched = 0
+    for item in object_array:
+        all_match = True
+        for key,value in to_match.items():
+            if item[key] != value:
+                all_match = False
+        if not all_match:
+            continue
+        elif should_not_find == True:
+            num_matched = num_matched+1
+        for key,value in expected.items():
+            if item[key] != value:
+                raise AssertionError("%s : expected %s=%s"%(str(item), str(key), str(value)))
+            num_matched = num_matched+1
+    if num_matched == 0 and should_not_find != True:
+        raise AssertionError("No objects matched %s"%(str(to_match)))
+    if num_matched > 0 and should_not_find == True:
+        raise AssertionError("Objects were found %s"%(str(to_match)))
 
+def satoshi_round(amount):
+    return Decimal(amount).quantize(Decimal('0.00000001'), rounding=ROUND_DOWN)
+
+# Helper to create at least "count" utxos
+# Pass in a fee that is sufficient for relay and mining new transactions.
 def create_confirmed_utxos(fee, node, count):
     node.generate(int(0.5*count)+101)
     utxos = node.listunspent()
@@ -454,6 +498,8 @@ def create_confirmed_utxos(fee, node, count):
     assert(len(utxos) >= count)
     return utxos
 
+# Create large OP_RETURN txouts that can be appended to a transaction
+# to make it large (helper for constructing large transactions).
 def gen_return_txouts():
     # Some pre-processing to create a bunch of OP_RETURN txouts to insert into transactions we create
     # So we have big transactions (and therefore can't fit very many into each block)
@@ -472,6 +518,16 @@ def gen_return_txouts():
         txouts = txouts + script_pubkey
     return txouts
 
+def create_tx(node, coinbase, to_address, amount):
+    inputs = [{ "txid" : coinbase, "vout" : 0}]
+    outputs = { to_address : amount }
+    rawtx = node.createrawtransaction(inputs, outputs)
+    signresult = node.signrawtransaction(rawtx)
+    assert_equal(signresult["complete"], True)
+    return signresult["hex"]
+
+# Create a spend of each passed-in utxo, splicing in "txouts" to each raw
+# transaction to make it large.  See gen_return_txouts() above.
 def create_lots_of_big_transactions(node, txouts, utxos, fee):
     addr = node.getnewaddress()
     txids = []
diff --git a/qa/rpc-tests/wallet.py b/qa/rpc-tests/wallet.py
index 2c0a009ca..fd2865167 100755
--- a/qa/rpc-tests/wallet.py
+++ b/qa/rpc-tests/wallet.py
@@ -3,7 +3,6 @@
 # Distributed under the MIT software license, see the accompanying
 # file COPYING or http://www.opensource.org/licenses/mit-license.php.
 
-
 from test_framework.test_framework import BitcoinTestFramework
 from test_framework.util import *
 
@@ -33,6 +32,12 @@ class WalletTest (BitcoinTestFramework):
         self.sync_all()
 
     def run_test (self):
+
+        # Check that there's no UTXO on none of the nodes
+        assert_equal(len(self.nodes[0].listunspent()), 0)
+        assert_equal(len(self.nodes[1].listunspent()), 0)
+        assert_equal(len(self.nodes[2].listunspent()), 0)
+
         print "Mining blocks..."
 
         self.nodes[0].generate(1)
@@ -49,6 +54,11 @@ class WalletTest (BitcoinTestFramework):
         assert_equal(self.nodes[1].getbalance(), 50)
         assert_equal(self.nodes[2].getbalance(), 0)
 
+        # Check that only first and second nodes have UTXOs
+        assert_equal(len(self.nodes[0].listunspent()), 1)
+        assert_equal(len(self.nodes[1].listunspent()), 1)
+        assert_equal(len(self.nodes[2].listunspent()), 0)
+
         # Send 21 BTC from 0 to 2 using sendtoaddress call.
         # Second transaction will be child of first, and will require a fee
         self.nodes[0].sendtoaddress(self.nodes[2].getnewaddress(), 11)
@@ -61,6 +71,15 @@ class WalletTest (BitcoinTestFramework):
         self.nodes[0].generate(1)
         self.sync_all()
 
+        # Exercise locking of unspent outputs
+        unspent_0 = self.nodes[2].listunspent()[0]
+        unspent_0 = {"txid": unspent_0["txid"], "vout": unspent_0["vout"]}
+        self.nodes[2].lockunspent(False, [unspent_0])
+        assert_raises(JSONRPCException, self.nodes[2].sendtoaddress, self.nodes[2].getnewaddress(), 20)
+        assert_equal([unspent_0], self.nodes[2].listlockunspent())
+        self.nodes[2].lockunspent(True, [unspent_0])
+        assert_equal(len(self.nodes[2].listlockunspent()), 0)
+
         # Have node1 generate 100 blocks (so node0 can recover the fee)
         self.nodes[1].generate(100)
         self.sync_all()
@@ -150,6 +169,10 @@ class WalletTest (BitcoinTestFramework):
 
         assert(txid1 in self.nodes[3].getrawmempool())
 
+        # Exercise balance rpcs
+        assert_equal(self.nodes[0].getwalletinfo()["unconfirmed_balance"], 1)
+        assert_equal(self.nodes[0].getunconfirmedbalance(), 1)
+
         #check if we can list zero value tx as available coins
         #1. create rawtx
         #2. hex-changed one output to 0.0
@@ -234,28 +257,53 @@ class WalletTest (BitcoinTestFramework):
         txObj = self.nodes[0].gettransaction(txId)
         assert_equal(txObj['amount'], Decimal('-0.0001'))
 
-        #this should fail
-        errorString = ""
         try:
             txId  = self.nodes[0].sendtoaddress(self.nodes[2].getnewaddress(), "1f-4")
-        except JSONRPCException,e:
-            errorString = e.error['message']
+        except JSONRPCException as e:
+            assert("Invalid amount" in e.error['message'])
+        else:
+            raise AssertionError("Must not parse invalid amounts")
 
-        assert_equal("Invalid amount" in errorString, True)
 
-        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:
-            errorString = e.error['message']
+            self.nodes[0].generate("2")
+            raise AssertionError("Must not accept strings as numeric")
+        except JSONRPCException as e:
+            assert("not an integer" in e.error['message'])
 
-        assert_equal("not an integer" in errorString, True)
+        # Import address and private key to check correct behavior of spendable unspents
+        # 1. Send some coins to generate new UTXO
+        address_to_import = self.nodes[2].getnewaddress()
+        txid = self.nodes[0].sendtoaddress(address_to_import, 1)
+        self.nodes[0].generate(1)
+        self.sync_all()
+
+        # 2. Import address from node2 to node1
+        self.nodes[1].importaddress(address_to_import)
+
+        # 3. Validate that the imported address is watch-only on node1
+        assert(self.nodes[1].validateaddress(address_to_import)["iswatchonly"])
+
+        # 4. Check that the unspents after import are not spendable
+        assert_array_result(self.nodes[1].listunspent(),
+                           {"address": address_to_import},
+                           {"spendable": False})
+
+        # 5. Import private key of the previously imported address on node1
+        priv_key = self.nodes[2].dumpprivkey(address_to_import)
+        self.nodes[1].importprivkey(priv_key)
+
+        # 6. Check that the unspents are now spendable on node1
+        assert_array_result(self.nodes[1].listunspent(),
+                           {"address": address_to_import},
+                           {"spendable": True})
 
         #check if wallet or blochchain maintenance changes the balance
         self.sync_all()
-        self.nodes[0].generate(1)
+        blocks = self.nodes[0].generate(2)
         self.sync_all()
         balance_nodes = [self.nodes[i].getbalance() for i in range(3)]
+        block_count = self.nodes[0].getblockcount()
 
         maintenance = [
             '-rescan',
@@ -265,15 +313,21 @@ class WalletTest (BitcoinTestFramework):
             '-salvagewallet',
         ]
         for m in maintenance:
+            print "check " + m
             stop_nodes(self.nodes)
             wait_bitcoinds()
             self.nodes = start_nodes(3, self.options.tmpdir, [[m]] * 3)
-            connect_nodes_bi(self.nodes,0,1)
-            connect_nodes_bi(self.nodes,1,2)
-            connect_nodes_bi(self.nodes,0,2)
-            self.sync_all()
+            while m == '-reindex' and [block_count] * 3 != [self.nodes[i].getblockcount() for i in range(3)]:
+                # reindex will leave rpc warm up "early"; Wait for it to finish
+                time.sleep(0.1)
             assert_equal(balance_nodes, [self.nodes[i].getbalance() for i in range(3)])
 
+        # Exercise listsinceblock with the last two blocks
+        coinbase_tx_1 = self.nodes[0].listsinceblock(blocks[0])
+        assert_equal(coinbase_tx_1["lastblock"], blocks[1])
+        assert_equal(len(coinbase_tx_1["transactions"]), 1)
+        assert_equal(coinbase_tx_1["transactions"][0]["blockhash"], blocks[1])
+        assert_equal(len(self.nodes[0].listsinceblock(blocks[1])["transactions"]), 0)
 
 if __name__ == '__main__':
     WalletTest ().main ()
diff --git a/qa/rpc-tests/zapwallettxes.py b/qa/rpc-tests/zapwallettxes.py
index 1ee0f79ac..1ba4ded24 100755
--- a/qa/rpc-tests/zapwallettxes.py
+++ b/qa/rpc-tests/zapwallettxes.py
@@ -65,14 +65,8 @@ class ZapWalletTXesTest (BitcoinTestFramework):
         #restart bitcoind with zapwallettxes
         self.nodes[0] = start_node(0,self.options.tmpdir, ["-zapwallettxes=1"])
         
-        aException = False
-        try:
-            tx3 = self.nodes[0].gettransaction(txid3)
-        except JSONRPCException,e:
-            print e
-            aException = True
-        
-        assert_equal(aException, True) #there must be a expection because the unconfirmed wallettx0 must be gone by now
+        assert_raises(JSONRPCException, self.nodes[0].gettransaction, [txid3])
+        #there must be a expection because the unconfirmed wallettx0 must be gone by now
 
         tx0 = self.nodes[0].gettransaction(txid0)
         assert_equal(tx0['txid'], txid0) #tx0 (confirmed) must still be available because it was confirmed
diff --git a/qa/rpc-tests/zmq_test.py b/qa/rpc-tests/zmq_test.py
index 88532541a..3a8d62ef2 100755
--- a/qa/rpc-tests/zmq_test.py
+++ b/qa/rpc-tests/zmq_test.py
@@ -28,8 +28,8 @@ class ZMQTest (BitcoinTestFramework):
     def setup_nodes(self):
         self.zmqContext = zmq.Context()
         self.zmqSubSocket = self.zmqContext.socket(zmq.SUB)
-        self.zmqSubSocket.setsockopt(zmq.SUBSCRIBE, "hashblock")
-        self.zmqSubSocket.setsockopt(zmq.SUBSCRIBE, "hashtx")
+        self.zmqSubSocket.setsockopt(zmq.SUBSCRIBE, b"hashblock")
+        self.zmqSubSocket.setsockopt(zmq.SUBSCRIBE, b"hashtx")
         self.zmqSubSocket.connect("tcp://127.0.0.1:%i" % self.port)
         return start_nodes(4, self.options.tmpdir, extra_args=[
             ['-zmqpubhashtx=tcp://127.0.0.1:'+str(self.port), '-zmqpubhashblock=tcp://127.0.0.1:'+str(self.port)],
@@ -46,13 +46,13 @@ class ZMQTest (BitcoinTestFramework):
 
         print "listen..."
         msg = self.zmqSubSocket.recv_multipart()
-        topic = str(msg[0])
+        topic = msg[0]
         body = msg[1]
 
         msg = self.zmqSubSocket.recv_multipart()
-        topic = str(msg[0])
+        topic = msg[0]
         body = msg[1]
-        blkhash = binascii.hexlify(body)
+        blkhash = bytes_to_hex_str(body)
 
         assert_equal(genhashes[0], blkhash) #blockhash from generate must be equal to the hash received over zmq
 
@@ -63,10 +63,10 @@ class ZMQTest (BitcoinTestFramework):
         zmqHashes = []
         for x in range(0,n*2):
             msg = self.zmqSubSocket.recv_multipart()
-            topic = str(msg[0])
+            topic = msg[0]
             body = msg[1]
-            if topic == "hashblock":
-                zmqHashes.append(binascii.hexlify(body))
+            if topic == b"hashblock":
+                zmqHashes.append(bytes_to_hex_str(body))
 
         for x in range(0,n):
             assert_equal(genhashes[x], zmqHashes[x]) #blockhash from generate must be equal to the hash received over zmq
@@ -77,11 +77,11 @@ class ZMQTest (BitcoinTestFramework):
 
         # now we should receive a zmq msg because the tx was broadcast
         msg = self.zmqSubSocket.recv_multipart()
-        topic = str(msg[0])
+        topic = msg[0]
         body = msg[1]
         hashZMQ = ""
-        if topic == "hashtx":
-            hashZMQ = binascii.hexlify(body)
+        if topic == b"hashtx":
+            hashZMQ = bytes_to_hex_str(body)
 
         assert_equal(hashRPC, hashZMQ) #blockhash from generate must be equal to the hash received over zmq
 
diff --git a/src/test/bctest.py b/src/test/bctest.py
index 3a8d0ea51..ae958cfe3 100644
--- a/src/test/bctest.py
+++ b/src/test/bctest.py
@@ -2,6 +2,7 @@
 # Distributed under the MIT software license, see the accompanying
 # file COPYING or http://www.opensource.org/licenses/mit-license.php.
 
+from __future__ import division,print_function,unicode_literals
 import subprocess
 import os
 import json
diff --git a/src/test/util_tests.cpp b/src/test/util_tests.cpp
index 28cecfffa..517e6945c 100644
--- a/src/test/util_tests.cpp
+++ b/src/test/util_tests.cpp
@@ -196,6 +196,8 @@ BOOST_AUTO_TEST_CASE(util_ParseMoney)
     BOOST_CHECK_EQUAL(ret, COIN*10);
     BOOST_CHECK(ParseMoney("1.00", ret));
     BOOST_CHECK_EQUAL(ret, COIN);
+    BOOST_CHECK(ParseMoney("1", ret));
+    BOOST_CHECK_EQUAL(ret, COIN);
     BOOST_CHECK(ParseMoney("0.1", ret));
     BOOST_CHECK_EQUAL(ret, COIN/10);
     BOOST_CHECK(ParseMoney("0.01", ret));
@@ -215,6 +217,9 @@ BOOST_AUTO_TEST_CASE(util_ParseMoney)
 
     // Attempted 63 bit overflow should fail
     BOOST_CHECK(!ParseMoney("92233720368.54775808", ret));
+
+    // Parsing negative amounts must fail
+    BOOST_CHECK(!ParseMoney("-1", ret));
 }
 
 BOOST_AUTO_TEST_CASE(util_IsHex)