scripted-diff: test: Use py3.5 bytes::hex() method

-BEGIN VERIFY SCRIPT-
sed -i -e "s/def bytes_to_hex_str/def b_2_x/g" $(git grep -l bytes_to_hex_str)

export RE_B_0="[^()]*"                          # match no bracket
export RE_B_1="${RE_B_0}\(${RE_B_0}\)${RE_B_0}" # match exactly one ()
export RE_B_2="${RE_B_0}\(${RE_B_1}\)${RE_B_0}" # match wrapped (())

export RE_M="(b2x|bytes_to_hex_str)\(((${RE_B_0}|${RE_B_1}|${RE_B_2})*)\)"

sed -i --regexp-extended -e "s/${RE_M}/\2.hex()/g"      $(git grep -l -E '(b2x|bytes_to_hex_str)')

sed -i --regexp-extended -e "/  +bytes_to_hex_str( as b2x)?,/d"    $(git grep -l bytes_to_hex_str)
sed -i --regexp-extended -e "s/ +bytes_to_hex_str( as b2x)?,//g"   $(git grep -l bytes_to_hex_str)
sed -i --regexp-extended -e "s/, bytes_to_hex_str( as b2x)?//g"    $(git grep -l bytes_to_hex_str)

export RE_M="(binascii\.)?hexlify\(((${RE_B_0}|${RE_B_1}|${RE_B_2})*)\).decode\(${RE_B_0}\)"

sed -i --regexp-extended -e "s/${RE_M}/\2.hex()/g" $(git grep -l hexlify -- ':(exclude)share')

sed -i --regexp-extended -e  "/from binascii import hexlify$/d" $(git grep -l hexlify -- ':(exclude)share')
sed -i --regexp-extended -e "s/(from binascii import) .*hexlify/\1 unhexlify/g" $(git grep -l hexlify -- ':(exclude)share')

sed -i -e 's/ignore-names "/ignore-names "b_2_x,/g' ./test/lint/lint-python-dead-code.sh
-END VERIFY SCRIPT-

26 files changed, 134 insertions, 146 deletions

diff --git a/contrib/linearize/linearize-data.py b/contrib/linearize/linearize-data.py
index 56c1fbfc92..468aec04b5 100755
--- a/contrib/linearize/linearize-data.py
+++ b/contrib/linearize/linearize-data.py
@@ -16,7 +16,7 @@ import hashlib
 import datetime
 import time
 from collections import namedtuple
-from binascii import hexlify, unhexlify
+from binascii import unhexlify
 
 settings = {}
 
@@ -61,7 +61,7 @@ def calc_hash_str(blk_hdr):
     hash = calc_hdr_hash(blk_hdr)
     hash = bufreverse(hash)
     hash = wordreverse(hash)
-    hash_str = hexlify(hash).decode('utf-8')
+    hash_str = hash.hex()
     return hash_str
 
 def get_blk_dt(blk_hdr):
@@ -213,7 +213,7 @@ class BlockDataCopier:
 
             inMagic = inhdr[:4]
             if (inMagic != self.settings['netmagic']):
-                print("Invalid magic: " + hexlify(inMagic).decode('utf-8'))
+                print("Invalid magic: " + inMagic.hex())
                 return
             inLenLE = inhdr[4:]
             su = struct.unpack("<I", inLenLE)
diff --git a/test/functional/feature_bip68_sequence.py b/test/functional/feature_bip68_sequence.py
index 8466f851ca..a1e2259bed 100755
--- a/test/functional/feature_bip68_sequence.py
+++ b/test/functional/feature_bip68_sequence.py
@@ -10,7 +10,7 @@ from test_framework.blocktools import create_block, create_coinbase, add_witness
 from test_framework.messages import COIN, COutPoint, CTransaction, CTxIn, CTxOut, FromHex, ToHex
 from test_framework.script import CScript
 from test_framework.test_framework import BitcoinTestFramework
-from test_framework.util import assert_equal, assert_greater_than, assert_raises_rpc_error, bytes_to_hex_str, get_bip9_status, satoshi_round, sync_blocks
+from test_framework.util import assert_equal, assert_greater_than, assert_raises_rpc_error, get_bip9_status, satoshi_round, sync_blocks
 
 SEQUENCE_LOCKTIME_DISABLE_FLAG = (1<<31)
 SEQUENCE_LOCKTIME_TYPE_FLAG = (1<<22) # this means use time (0 means height)
@@ -372,7 +372,7 @@ class BIP68Test(BitcoinTestFramework):
         add_witness_commitment(block)
         block.solve()
 
-        self.nodes[0].submitblock(bytes_to_hex_str(block.serialize(True)))
+        self.nodes[0].submitblock(block.serialize(True).hex())
         assert_equal(self.nodes[0].getbestblockhash(), block.hash)
 
     def activateCSV(self):
diff --git a/test/functional/feature_cltv.py b/test/functional/feature_cltv.py
index 96c5e49b0e..b422bf2873 100755
--- a/test/functional/feature_cltv.py
+++ b/test/functional/feature_cltv.py
@@ -15,7 +15,6 @@ from test_framework.script import CScript, OP_1NEGATE, OP_CHECKLOCKTIMEVERIFY, O
 from test_framework.test_framework import BitcoinTestFramework
 from test_framework.util import (
     assert_equal,
-    bytes_to_hex_str,
     hex_str_to_bytes,
 )
 
@@ -114,7 +113,7 @@ class BIP65Test(BitcoinTestFramework):
         # rejected from the mempool for exactly that reason.
         assert_equal(
             [{'txid': spendtx.hash, 'allowed': False, 'reject-reason': '64: non-mandatory-script-verify-flag (Negative locktime)'}],
-            self.nodes[0].testmempoolaccept(rawtxs=[bytes_to_hex_str(spendtx.serialize())], allowhighfees=True)
+            self.nodes[0].testmempoolaccept(rawtxs=[spendtx.serialize().hex()], allowhighfees=True)
         )
 
         # Now we verify that a block with this transaction is also invalid.
diff --git a/test/functional/feature_dersig.py b/test/functional/feature_dersig.py
index 8ff9498ef3..18416c3ab1 100755
--- a/test/functional/feature_dersig.py
+++ b/test/functional/feature_dersig.py
@@ -14,7 +14,6 @@ from test_framework.script import CScript
 from test_framework.test_framework import BitcoinTestFramework
 from test_framework.util import (
     assert_equal,
-    bytes_to_hex_str,
     wait_until,
 )
 
@@ -103,7 +102,7 @@ class BIP66Test(BitcoinTestFramework):
         # rejected from the mempool for exactly that reason.
         assert_equal(
             [{'txid': spendtx.hash, 'allowed': False, 'reject-reason': '64: non-mandatory-script-verify-flag (Non-canonical DER signature)'}],
-            self.nodes[0].testmempoolaccept(rawtxs=[bytes_to_hex_str(spendtx.serialize())], allowhighfees=True)
+            self.nodes[0].testmempoolaccept(rawtxs=[spendtx.serialize().hex()], allowhighfees=True)
         )
 
         # Now we verify that a block with this transaction is also invalid.
diff --git a/test/functional/feature_nulldummy.py b/test/functional/feature_nulldummy.py
index eb76089d9c..08a0911470 100755
--- a/test/functional/feature_nulldummy.py
+++ b/test/functional/feature_nulldummy.py
@@ -18,7 +18,7 @@ from test_framework.blocktools import create_coinbase, create_block, create_tran
 from test_framework.messages import CTransaction
 from test_framework.script import CScript
 from test_framework.test_framework import BitcoinTestFramework
-from test_framework.util import assert_equal, assert_raises_rpc_error, bytes_to_hex_str
+from test_framework.util import assert_equal, assert_raises_rpc_error
 
 NULLDUMMY_ERROR = "non-mandatory-script-verify-flag (Dummy CHECKMULTISIG argument must be zero) (code 64)"
 
@@ -64,17 +64,17 @@ class NULLDUMMYTest(BitcoinTestFramework):
 
         self.log.info("Test 1: NULLDUMMY compliant base transactions should be accepted to mempool and mined before activation [430]")
         test1txs = [create_transaction(self.nodes[0], coinbase_txid[0], self.ms_address, amount=49)]
-        txid1 = self.nodes[0].sendrawtransaction(bytes_to_hex_str(test1txs[0].serialize_with_witness()), True)
+        txid1 = self.nodes[0].sendrawtransaction(test1txs[0].serialize_with_witness().hex(), True)
         test1txs.append(create_transaction(self.nodes[0], txid1, self.ms_address, amount=48))
-        txid2 = self.nodes[0].sendrawtransaction(bytes_to_hex_str(test1txs[1].serialize_with_witness()), True)
+        txid2 = self.nodes[0].sendrawtransaction(test1txs[1].serialize_with_witness().hex(), True)
         test1txs.append(create_transaction(self.nodes[0], coinbase_txid[1], self.wit_ms_address, amount=49))
-        txid3 = self.nodes[0].sendrawtransaction(bytes_to_hex_str(test1txs[2].serialize_with_witness()), True)
+        txid3 = self.nodes[0].sendrawtransaction(test1txs[2].serialize_with_witness().hex(), True)
         self.block_submit(self.nodes[0], test1txs, False, True)
 
         self.log.info("Test 2: Non-NULLDUMMY base multisig transaction should not be accepted to mempool before activation")
         test2tx = create_transaction(self.nodes[0], txid2, self.ms_address, amount=47)
         trueDummy(test2tx)
-        assert_raises_rpc_error(-26, NULLDUMMY_ERROR, self.nodes[0].sendrawtransaction, bytes_to_hex_str(test2tx.serialize_with_witness()), True)
+        assert_raises_rpc_error(-26, NULLDUMMY_ERROR, self.nodes[0].sendrawtransaction, test2tx.serialize_with_witness().hex(), True)
 
         self.log.info("Test 3: Non-NULLDUMMY base transactions should be accepted in a block before activation [431]")
         self.block_submit(self.nodes[0], [test2tx], False, True)
@@ -83,19 +83,19 @@ class NULLDUMMYTest(BitcoinTestFramework):
         test4tx = create_transaction(self.nodes[0], test2tx.hash, self.address, amount=46)
         test6txs = [CTransaction(test4tx)]
         trueDummy(test4tx)
-        assert_raises_rpc_error(-26, NULLDUMMY_ERROR, self.nodes[0].sendrawtransaction, bytes_to_hex_str(test4tx.serialize_with_witness()), True)
+        assert_raises_rpc_error(-26, NULLDUMMY_ERROR, self.nodes[0].sendrawtransaction, test4tx.serialize_with_witness().hex(), True)
         self.block_submit(self.nodes[0], [test4tx])
 
         self.log.info("Test 5: Non-NULLDUMMY P2WSH multisig transaction invalid after activation")
         test5tx = create_transaction(self.nodes[0], txid3, self.wit_address, amount=48)
         test6txs.append(CTransaction(test5tx))
         test5tx.wit.vtxinwit[0].scriptWitness.stack[0] = b'\x01'
-        assert_raises_rpc_error(-26, NULLDUMMY_ERROR, self.nodes[0].sendrawtransaction, bytes_to_hex_str(test5tx.serialize_with_witness()), True)
+        assert_raises_rpc_error(-26, NULLDUMMY_ERROR, self.nodes[0].sendrawtransaction, test5tx.serialize_with_witness().hex(), True)
         self.block_submit(self.nodes[0], [test5tx], True)
 
         self.log.info("Test 6: NULLDUMMY compliant base/witness transactions should be accepted to mempool and in block after activation [432]")
         for i in test6txs:
-            self.nodes[0].sendrawtransaction(bytes_to_hex_str(i.serialize_with_witness()), True)
+            self.nodes[0].sendrawtransaction(i.serialize_with_witness().hex(), True)
         self.block_submit(self.nodes[0], test6txs, True, True)
 
     def block_submit(self, node, txs, witness=False, accept=False):
@@ -108,7 +108,7 @@ class NULLDUMMYTest(BitcoinTestFramework):
         witness and add_witness_commitment(block)
         block.rehash()
         block.solve()
-        node.submitblock(bytes_to_hex_str(block.serialize(True)))
+        node.submitblock(block.serialize(True).hex())
         if (accept):
             assert_equal(node.getbestblockhash(), block.hash)
             self.tip = block.sha256
diff --git a/test/functional/feature_rbf.py b/test/functional/feature_rbf.py
index ff7c2b23bf..274c4922dc 100755
--- a/test/functional/feature_rbf.py
+++ b/test/functional/feature_rbf.py
@@ -9,12 +9,12 @@ from decimal import Decimal
 from test_framework.messages import COIN, COutPoint, CTransaction, CTxIn, CTxOut
 from test_framework.script import CScript, OP_DROP
 from test_framework.test_framework import BitcoinTestFramework
-from test_framework.util import assert_equal, assert_raises_rpc_error, bytes_to_hex_str, satoshi_round
+from test_framework.util import assert_equal, assert_raises_rpc_error, satoshi_round
 
 MAX_REPLACEMENT_LIMIT = 100
 
 def txToHex(tx):
-    return bytes_to_hex_str(tx.serialize())
+    return tx.serialize().hex()
 
 def make_utxo(node, amount, confirmed=True, scriptPubKey=CScript([1])):
     """Create a txout with a given amount and scriptPubKey
diff --git a/test/functional/feature_segwit.py b/test/functional/feature_segwit.py
index 658a8cd75e..c8505f34ab 100755
--- a/test/functional/feature_segwit.py
+++ b/test/functional/feature_segwit.py
@@ -18,7 +18,7 @@ from test_framework.blocktools import witness_script, send_to_witness
 from test_framework.messages import COIN, COutPoint, CTransaction, CTxIn, CTxOut, FromHex, sha256, ToHex
 from test_framework.script import CScript, OP_HASH160, OP_CHECKSIG, OP_0, hash160, OP_EQUAL, OP_DUP, OP_EQUALVERIFY, OP_1, OP_2, OP_CHECKMULTISIG, OP_TRUE, OP_DROP
 from test_framework.test_framework import BitcoinTestFramework
-from test_framework.util import assert_equal, assert_raises_rpc_error, bytes_to_hex_str, connect_nodes, hex_str_to_bytes, sync_blocks, try_rpc
+from test_framework.util import assert_equal, assert_raises_rpc_error, connect_nodes, hex_str_to_bytes, sync_blocks, try_rpc
 
 NODE_0 = 0
 NODE_2 = 2
@@ -181,7 +181,7 @@ class SegWitTest(BitcoinTestFramework):
             assert(self.nodes[1].getrawtransaction(tx_id, False, blockhash) == self.nodes[2].getrawtransaction(tx_id, False, blockhash))
             assert(self.nodes[0].getrawtransaction(tx_id, False, blockhash) != self.nodes[2].gettransaction(tx_id)["hex"])
             assert(self.nodes[1].getrawtransaction(tx_id, False, blockhash) == self.nodes[2].gettransaction(tx_id)["hex"])
-            assert(self.nodes[0].getrawtransaction(tx_id, False, blockhash) == bytes_to_hex_str(tx.serialize_without_witness()))
+            assert(self.nodes[0].getrawtransaction(tx_id, False, blockhash) == tx.serialize_without_witness().hex())
 
         self.log.info("Verify witness txs without witness data are invalid after the fork")
         self.fail_accept(self.nodes[2], 'non-mandatory-script-verify-flag (Witness program hash mismatch) (code 64)', wit_ids[NODE_2][WIT_V0][2], sign=False)
@@ -392,22 +392,22 @@ class SegWitTest(BitcoinTestFramework):
             v = self.nodes[0].getaddressinfo(i)
             if (v['isscript']):
                 bare = hex_str_to_bytes(v['hex'])
-                importlist.append(bytes_to_hex_str(bare))
-                importlist.append(bytes_to_hex_str(CScript([OP_0, sha256(bare)])))
+                importlist.append(bare.hex())
+                importlist.append(CScript([OP_0, sha256(bare)]).hex())
             else:
                 pubkey = hex_str_to_bytes(v['pubkey'])
                 p2pk = CScript([pubkey, OP_CHECKSIG])
                 p2pkh = CScript([OP_DUP, OP_HASH160, hash160(pubkey), OP_EQUALVERIFY, OP_CHECKSIG])
-                importlist.append(bytes_to_hex_str(p2pk))
-                importlist.append(bytes_to_hex_str(p2pkh))
-                importlist.append(bytes_to_hex_str(CScript([OP_0, hash160(pubkey)])))
-                importlist.append(bytes_to_hex_str(CScript([OP_0, sha256(p2pk)])))
-                importlist.append(bytes_to_hex_str(CScript([OP_0, sha256(p2pkh)])))
+                importlist.append(p2pk.hex())
+                importlist.append(p2pkh.hex())
+                importlist.append(CScript([OP_0, hash160(pubkey)]).hex())
+                importlist.append(CScript([OP_0, sha256(p2pk)]).hex())
+                importlist.append(CScript([OP_0, sha256(p2pkh)]).hex())
 
-        importlist.append(bytes_to_hex_str(unsolvablep2pkh))
-        importlist.append(bytes_to_hex_str(unsolvablep2wshp2pkh))
-        importlist.append(bytes_to_hex_str(op1))
-        importlist.append(bytes_to_hex_str(p2wshop1))
+        importlist.append(unsolvablep2pkh.hex())
+        importlist.append(unsolvablep2wshp2pkh.hex())
+        importlist.append(op1.hex())
+        importlist.append(p2wshop1.hex())
 
         for i in importlist:
             # import all generated addresses. The wallet already has the private keys for some of these, so catch JSON RPC
@@ -535,7 +535,7 @@ class SegWitTest(BitcoinTestFramework):
         for i in script_list:
             tx.vout.append(CTxOut(10000000, i))
         tx.rehash()
-        signresults = self.nodes[0].signrawtransactionwithwallet(bytes_to_hex_str(tx.serialize_without_witness()))['hex']
+        signresults = self.nodes[0].signrawtransactionwithwallet(tx.serialize_without_witness().hex())['hex']
         txid = self.nodes[0].sendrawtransaction(signresults, True)
         txs_mined[txid] = self.nodes[0].generate(1)[0]
         sync_blocks(self.nodes)
@@ -587,7 +587,7 @@ class SegWitTest(BitcoinTestFramework):
                 tx.vin.append(CTxIn(COutPoint(int('0x' + i, 0), j)))
         tx.vout.append(CTxOut(0, CScript()))
         tx.rehash()
-        signresults = self.nodes[0].signrawtransactionwithwallet(bytes_to_hex_str(tx.serialize_without_witness()))['hex']
+        signresults = self.nodes[0].signrawtransactionwithwallet(tx.serialize_without_witness().hex())['hex']
         self.nodes[0].sendrawtransaction(signresults, True)
         self.nodes[0].generate(1)
         sync_blocks(self.nodes)
diff --git a/test/functional/interface_rest.py b/test/functional/interface_rest.py
index f33040242c..2844e42f62 100755
--- a/test/functional/interface_rest.py
+++ b/test/functional/interface_rest.py
@@ -152,7 +152,7 @@ class RESTTest (BitcoinTestFramework):
         bin_response = self.test_rest_request("/getutxos", http_method='POST', req_type=ReqType.BIN, body=bin_request, ret_type=RetType.BYTES)
         output = BytesIO(bin_response)
         chain_height, = unpack("i", output.read(4))
-        response_hash = binascii.hexlify(output.read(32)[::-1]).decode('ascii')
+        response_hash = output.read(32)[::-1].hex()
 
         assert_equal(bb_hash, response_hash)  # check if getutxo's chaintip during calculation was fine
         assert_equal(chain_height, 102)  # chain height must be 102
@@ -252,7 +252,7 @@ class RESTTest (BitcoinTestFramework):
         resp_hex = self.test_rest_request("/blockhashbyheight/{}".format(block_json_obj['height']), req_type=ReqType.HEX, ret_type=RetType.OBJ)
         assert_equal(resp_hex.read().decode('utf-8').rstrip(), bb_hash)
         resp_bytes = self.test_rest_request("/blockhashbyheight/{}".format(block_json_obj['height']), req_type=ReqType.BIN, ret_type=RetType.BYTES)
-        blockhash = binascii.hexlify(resp_bytes[::-1]).decode('utf-8')
+        blockhash = resp_bytes[::-1].hex()
         assert_equal(blockhash, bb_hash)
 
         # Check invalid blockhashbyheight requests
diff --git a/test/functional/interface_zmq.py b/test/functional/interface_zmq.py
index 94fea37090..e59c0f32b3 100755
--- a/test/functional/interface_zmq.py
+++ b/test/functional/interface_zmq.py
@@ -10,7 +10,6 @@ from test_framework.test_framework import BitcoinTestFramework
 from test_framework.messages import CTransaction
 from test_framework.util import (
     assert_equal,
-    bytes_to_hex_str,
     hash256,
 )
 from io import BytesIO
@@ -94,17 +93,17 @@ class ZMQTest (BitcoinTestFramework):
             tx = CTransaction()
             tx.deserialize(BytesIO(hex))
             tx.calc_sha256()
-            assert_equal(tx.hash, bytes_to_hex_str(txid))
+            assert_equal(tx.hash, txid.hex())
 
             # Should receive the generated block hash.
-            hash = bytes_to_hex_str(self.hashblock.receive())
+            hash = self.hashblock.receive().hex()
             assert_equal(genhashes[x], hash)
             # The block should only have the coinbase txid.
-            assert_equal([bytes_to_hex_str(txid)], self.nodes[1].getblock(hash)["tx"])
+            assert_equal([txid.hex()], self.nodes[1].getblock(hash)["tx"])
 
             # Should receive the generated raw block.
             block = self.rawblock.receive()
-            assert_equal(genhashes[x], bytes_to_hex_str(hash256(block[:80])))
+            assert_equal(genhashes[x], hash256(block[:80]).hex())
 
         if self.is_wallet_compiled():
             self.log.info("Wait for tx from second node")
@@ -113,11 +112,11 @@ class ZMQTest (BitcoinTestFramework):
 
             # Should receive the broadcasted txid.
             txid = self.hashtx.receive()
-            assert_equal(payment_txid, bytes_to_hex_str(txid))
+            assert_equal(payment_txid, txid.hex())
 
             # Should receive the broadcasted raw transaction.
             hex = self.rawtx.receive()
-            assert_equal(payment_txid, bytes_to_hex_str(hash256(hex)))
+            assert_equal(payment_txid, hash256(hex).hex())
 
 
         self.log.info("Test the getzmqnotifications RPC")
diff --git a/test/functional/mempool_accept.py b/test/functional/mempool_accept.py
index efe720b9b1..f6a17eaf40 100755
--- a/test/functional/mempool_accept.py
+++ b/test/functional/mempool_accept.py
@@ -27,7 +27,6 @@ from test_framework.script import (
 from test_framework.util import (
     assert_equal,
     assert_raises_rpc_error,
-    bytes_to_hex_str,
     hex_str_to_bytes,
 )
 
@@ -101,7 +100,7 @@ class MempoolAcceptanceTest(BitcoinTestFramework):
         tx.deserialize(BytesIO(hex_str_to_bytes(raw_tx_final)))
         self.check_mempool_result(
             result_expected=[{'txid': tx.rehash(), 'allowed': True}],
-            rawtxs=[bytes_to_hex_str(tx.serialize())],
+            rawtxs=[tx.serialize().hex()],
             allowhighfees=True,
         )
         node.sendrawtransaction(hexstring=raw_tx_final, allowhighfees=True)
@@ -119,7 +118,7 @@ class MempoolAcceptanceTest(BitcoinTestFramework):
         tx.deserialize(BytesIO(hex_str_to_bytes(raw_tx_0)))
         tx.vout[0].nValue -= int(fee * COIN)  # Double the fee
         tx.vin[0].nSequence = BIP125_SEQUENCE_NUMBER + 1  # Now, opt out of RBF
-        raw_tx_0 = node.signrawtransactionwithwallet(bytes_to_hex_str(tx.serialize()))['hex']
+        raw_tx_0 = node.signrawtransactionwithwallet(tx.serialize().hex())['hex']
         tx.deserialize(BytesIO(hex_str_to_bytes(raw_tx_0)))
         txid_0 = tx.rehash()
         self.check_mempool_result(
@@ -129,14 +128,14 @@ class MempoolAcceptanceTest(BitcoinTestFramework):
 
         self.log.info('A transaction that conflicts with an unconfirmed tx')
         # Send the transaction that replaces the mempool transaction and opts out of replaceability
-        node.sendrawtransaction(hexstring=bytes_to_hex_str(tx.serialize()), allowhighfees=True)
+        node.sendrawtransaction(hexstring=tx.serialize().hex(), allowhighfees=True)
         # take original raw_tx_0
         tx.deserialize(BytesIO(hex_str_to_bytes(raw_tx_0)))
         tx.vout[0].nValue -= int(4 * fee * COIN)  # Set more fee
         # skip re-signing the tx
         self.check_mempool_result(
             result_expected=[{'txid': tx.rehash(), 'allowed': False, 'reject-reason': '18: txn-mempool-conflict'}],
-            rawtxs=[bytes_to_hex_str(tx.serialize())],
+            rawtxs=[tx.serialize().hex()],
             allowhighfees=True,
         )
 
@@ -146,13 +145,13 @@ class MempoolAcceptanceTest(BitcoinTestFramework):
         # skip re-signing the tx
         self.check_mempool_result(
             result_expected=[{'txid': tx.rehash(), 'allowed': False, 'reject-reason': 'missing-inputs'}],
-            rawtxs=[bytes_to_hex_str(tx.serialize())],
+            rawtxs=[tx.serialize().hex()],
         )
 
         self.log.info('A transaction with missing inputs, that existed once in the past')
         tx.deserialize(BytesIO(hex_str_to_bytes(raw_tx_0)))
         tx.vin[0].prevout.n = 1  # Set vout to 1, to spend the other outpoint (49 coins) of the in-chain-tx we want to double spend
-        raw_tx_1 = node.signrawtransactionwithwallet(bytes_to_hex_str(tx.serialize()))['hex']
+        raw_tx_1 = node.signrawtransactionwithwallet(tx.serialize().hex())['hex']
         txid_1 = node.sendrawtransaction(hexstring=raw_tx_1, allowhighfees=True)
         # Now spend both to "clearly hide" the outputs, ie. remove the coins from the utxo set by spending them
         raw_tx_spend_both = node.signrawtransactionwithwallet(node.createrawtransaction(
@@ -184,17 +183,17 @@ class MempoolAcceptanceTest(BitcoinTestFramework):
         # Reference tx should be valid on itself
         self.check_mempool_result(
             result_expected=[{'txid': tx.rehash(), 'allowed': True}],
-            rawtxs=[bytes_to_hex_str(tx.serialize())],
+            rawtxs=[tx.serialize().hex()],
         )
 
         self.log.info('A transaction with no outputs')
         tx.deserialize(BytesIO(hex_str_to_bytes(raw_tx_reference)))
         tx.vout = []
         # Skip re-signing the transaction for context independent checks from now on
-        # tx.deserialize(BytesIO(hex_str_to_bytes(node.signrawtransactionwithwallet(bytes_to_hex_str(tx.serialize()))['hex'])))
+        # tx.deserialize(BytesIO(hex_str_to_bytes(node.signrawtransactionwithwallet(tx.serialize().hex())['hex'])))
         self.check_mempool_result(
             result_expected=[{'txid': tx.rehash(), 'allowed': False, 'reject-reason': '16: bad-txns-vout-empty'}],
-            rawtxs=[bytes_to_hex_str(tx.serialize())],
+            rawtxs=[tx.serialize().hex()],
         )
 
         self.log.info('A really large transaction')
@@ -202,7 +201,7 @@ class MempoolAcceptanceTest(BitcoinTestFramework):
         tx.vin = [tx.vin[0]] * math.ceil(MAX_BLOCK_BASE_SIZE / len(tx.vin[0].serialize()))
         self.check_mempool_result(
             result_expected=[{'txid': tx.rehash(), 'allowed': False, 'reject-reason': '16: bad-txns-oversize'}],
-            rawtxs=[bytes_to_hex_str(tx.serialize())],
+            rawtxs=[tx.serialize().hex()],
         )
 
         self.log.info('A transaction with negative output value')
@@ -210,7 +209,7 @@ class MempoolAcceptanceTest(BitcoinTestFramework):
         tx.vout[0].nValue *= -1
         self.check_mempool_result(
             result_expected=[{'txid': tx.rehash(), 'allowed': False, 'reject-reason': '16: bad-txns-vout-negative'}],
-            rawtxs=[bytes_to_hex_str(tx.serialize())],
+            rawtxs=[tx.serialize().hex()],
         )
 
         self.log.info('A transaction with too large output value')
@@ -218,7 +217,7 @@ class MempoolAcceptanceTest(BitcoinTestFramework):
         tx.vout[0].nValue = 21000000 * COIN + 1
         self.check_mempool_result(
             result_expected=[{'txid': tx.rehash(), 'allowed': False, 'reject-reason': '16: bad-txns-vout-toolarge'}],
-            rawtxs=[bytes_to_hex_str(tx.serialize())],
+            rawtxs=[tx.serialize().hex()],
         )
 
         self.log.info('A transaction with too large sum of output values')
@@ -227,7 +226,7 @@ class MempoolAcceptanceTest(BitcoinTestFramework):
         tx.vout[0].nValue = 21000000 * COIN
         self.check_mempool_result(
             result_expected=[{'txid': tx.rehash(), 'allowed': False, 'reject-reason': '16: bad-txns-txouttotal-toolarge'}],
-            rawtxs=[bytes_to_hex_str(tx.serialize())],
+            rawtxs=[tx.serialize().hex()],
         )
 
         self.log.info('A transaction with duplicate inputs')
@@ -235,7 +234,7 @@ class MempoolAcceptanceTest(BitcoinTestFramework):
         tx.vin = [tx.vin[0]] * 2
         self.check_mempool_result(
             result_expected=[{'txid': tx.rehash(), 'allowed': False, 'reject-reason': '16: bad-txns-inputs-duplicate'}],
-            rawtxs=[bytes_to_hex_str(tx.serialize())],
+            rawtxs=[tx.serialize().hex()],
         )
 
         self.log.info('A coinbase transaction')
@@ -244,7 +243,7 @@ class MempoolAcceptanceTest(BitcoinTestFramework):
         tx.deserialize(BytesIO(hex_str_to_bytes(raw_tx_coinbase_spent)))
         self.check_mempool_result(
             result_expected=[{'txid': tx.rehash(), 'allowed': False, 'reject-reason': '16: coinbase'}],
-            rawtxs=[bytes_to_hex_str(tx.serialize())],
+            rawtxs=[tx.serialize().hex()],
         )
 
         self.log.info('Some nonstandard transactions')
@@ -252,19 +251,19 @@ class MempoolAcceptanceTest(BitcoinTestFramework):
         tx.nVersion = 3  # A version currently non-standard
         self.check_mempool_result(
             result_expected=[{'txid': tx.rehash(), 'allowed': False, 'reject-reason': '64: version'}],
-            rawtxs=[bytes_to_hex_str(tx.serialize())],
+            rawtxs=[tx.serialize().hex()],
         )
         tx.deserialize(BytesIO(hex_str_to_bytes(raw_tx_reference)))
         tx.vout[0].scriptPubKey = CScript([OP_0])  # Some non-standard script
         self.check_mempool_result(
             result_expected=[{'txid': tx.rehash(), 'allowed': False, 'reject-reason': '64: scriptpubkey'}],
-            rawtxs=[bytes_to_hex_str(tx.serialize())],
+            rawtxs=[tx.serialize().hex()],
         )
         tx.deserialize(BytesIO(hex_str_to_bytes(raw_tx_reference)))
         tx.vin[0].scriptSig = CScript([OP_HASH160])  # Some not-pushonly scriptSig
         self.check_mempool_result(
             result_expected=[{'txid': tx.rehash(), 'allowed': False, 'reject-reason': '64: scriptsig-not-pushonly'}],
-            rawtxs=[bytes_to_hex_str(tx.serialize())],
+            rawtxs=[tx.serialize().hex()],
         )
         tx.deserialize(BytesIO(hex_str_to_bytes(raw_tx_reference)))
         output_p2sh_burn = CTxOut(nValue=540, scriptPubKey=CScript([OP_HASH160, hash160(b'burn'), OP_EQUAL]))
@@ -272,21 +271,21 @@ class MempoolAcceptanceTest(BitcoinTestFramework):
         tx.vout = [output_p2sh_burn] * num_scripts
         self.check_mempool_result(
             result_expected=[{'txid': tx.rehash(), 'allowed': False, 'reject-reason': '64: tx-size'}],
-            rawtxs=[bytes_to_hex_str(tx.serialize())],
+            rawtxs=[tx.serialize().hex()],
         )
         tx.deserialize(BytesIO(hex_str_to_bytes(raw_tx_reference)))
         tx.vout[0] = output_p2sh_burn
         tx.vout[0].nValue -= 1  # Make output smaller, such that it is dust for our policy
         self.check_mempool_result(
             result_expected=[{'txid': tx.rehash(), 'allowed': False, 'reject-reason': '64: dust'}],
-            rawtxs=[bytes_to_hex_str(tx.serialize())],
+            rawtxs=[tx.serialize().hex()],
         )
         tx.deserialize(BytesIO(hex_str_to_bytes(raw_tx_reference)))
         tx.vout[0].scriptPubKey = CScript([OP_RETURN, b'\xff'])
         tx.vout = [tx.vout[0]] * 2
         self.check_mempool_result(
             result_expected=[{'txid': tx.rehash(), 'allowed': False, 'reject-reason': '64: multi-op-return'}],
-            rawtxs=[bytes_to_hex_str(tx.serialize())],
+            rawtxs=[tx.serialize().hex()],
         )
 
         self.log.info('A timelocked transaction')
@@ -295,7 +294,7 @@ class MempoolAcceptanceTest(BitcoinTestFramework):
         tx.nLockTime = node.getblockcount() + 1
         self.check_mempool_result(
             result_expected=[{'txid': tx.rehash(), 'allowed': False, 'reject-reason': '64: non-final'}],
-            rawtxs=[bytes_to_hex_str(tx.serialize())],
+            rawtxs=[tx.serialize().hex()],
         )
 
         self.log.info('A transaction that is locked by BIP68 sequence logic')
@@ -304,7 +303,7 @@ class MempoolAcceptanceTest(BitcoinTestFramework):
         # Can skip re-signing the tx because of early rejection
         self.check_mempool_result(
             result_expected=[{'txid': tx.rehash(), 'allowed': False, 'reject-reason': '64: non-BIP68-final'}],
-            rawtxs=[bytes_to_hex_str(tx.serialize())],
+            rawtxs=[tx.serialize().hex()],
             allowhighfees=True,
         )
 
diff --git a/test/functional/mining_basic.py b/test/functional/mining_basic.py
index d0bef48cb6..788aabc192 100755
--- a/test/functional/mining_basic.py
+++ b/test/functional/mining_basic.py
@@ -27,7 +27,6 @@ from test_framework.test_framework import BitcoinTestFramework
 from test_framework.util import (
     assert_equal,
     assert_raises_rpc_error,
-    bytes_to_hex_str as b2x,
     connect_nodes_bi,
 )
 from test_framework.script import CScriptNum
@@ -36,7 +35,7 @@ from test_framework.script import CScriptNum
 def assert_template(node, block, expect, rehash=True):
     if rehash:
         block.hashMerkleRoot = block.calc_merkle_root()
-    rsp = node.getblocktemplate(template_request={'data': b2x(block.serialize()), 'mode': 'proposal', 'rules': ['segwit']})
+    rsp = node.getblocktemplate(template_request={'data': block.serialize().hex(), 'mode': 'proposal', 'rules': ['segwit']})
     assert_equal(rsp, expect)
 
 
@@ -64,8 +63,8 @@ class MiningTest(BitcoinTestFramework):
         def assert_submitblock(block, result_str_1, result_str_2=None):
             block.solve()
             result_str_2 = result_str_2 or 'duplicate-invalid'
-            assert_equal(result_str_1, node.submitblock(hexdata=b2x(block.serialize())))
-            assert_equal(result_str_2, node.submitblock(hexdata=b2x(block.serialize())))
+            assert_equal(result_str_1, node.submitblock(hexdata=block.serialize().hex()))
+            assert_equal(result_str_2, node.submitblock(hexdata=block.serialize().hex()))
 
         self.log.info('getmininginfo')
         mining_info = node.getmininginfo()
@@ -112,7 +111,7 @@ class MiningTest(BitcoinTestFramework):
         assert_template(node, block, None)
 
         self.log.info("submitblock: Test block decode failure")
-        assert_raises_rpc_error(-22, "Block decode failed", node.submitblock, b2x(block.serialize()[:-15]))
+        assert_raises_rpc_error(-22, "Block decode failed", node.submitblock, block.serialize()[:-15].hex())
 
         self.log.info("getblocktemplate: Test bad input hash for coinbase transaction")
         bad_block = copy.deepcopy(block)
@@ -121,10 +120,10 @@ class MiningTest(BitcoinTestFramework):
         assert_template(node, bad_block, 'bad-cb-missing')
 
         self.log.info("submitblock: Test invalid coinbase transaction")
-        assert_raises_rpc_error(-22, "Block does not start with a coinbase", node.submitblock, b2x(bad_block.serialize()))
+        assert_raises_rpc_error(-22, "Block does not start with a coinbase", node.submitblock, bad_block.serialize().hex())
 
         self.log.info("getblocktemplate: Test truncated final transaction")
-        assert_raises_rpc_error(-22, "Block decode failed", node.getblocktemplate, {'data': b2x(block.serialize()[:-1]), 'mode': 'proposal', 'rules': ['segwit']})
+        assert_raises_rpc_error(-22, "Block decode failed", node.getblocktemplate, {'data': block.serialize()[:-1].hex(), 'mode': 'proposal', 'rules': ['segwit']})
 
         self.log.info("getblocktemplate: Test duplicate transaction")
         bad_block = copy.deepcopy(block)
@@ -153,7 +152,7 @@ class MiningTest(BitcoinTestFramework):
         bad_block_sn = bytearray(block.serialize())
         assert_equal(bad_block_sn[BLOCK_HEADER_SIZE], 1)
         bad_block_sn[BLOCK_HEADER_SIZE] += 1
-        assert_raises_rpc_error(-22, "Block decode failed", node.getblocktemplate, {'data': b2x(bad_block_sn), 'mode': 'proposal', 'rules': ['segwit']})
+        assert_raises_rpc_error(-22, "Block decode failed", node.getblocktemplate, {'data': bad_block_sn.hex(), 'mode': 'proposal', 'rules': ['segwit']})
 
         self.log.info("getblocktemplate: Test bad bits")
         bad_block = copy.deepcopy(block)
@@ -184,7 +183,7 @@ class MiningTest(BitcoinTestFramework):
         self.log.info('submitheader tests')
         assert_raises_rpc_error(-22, 'Block header decode failed', lambda: node.submitheader(hexdata='xx' * BLOCK_HEADER_SIZE))
         assert_raises_rpc_error(-22, 'Block header decode failed', lambda: node.submitheader(hexdata='ff' * (BLOCK_HEADER_SIZE-2)))
-        assert_raises_rpc_error(-25, 'Must submit previous header', lambda: node.submitheader(hexdata=b2x(super(CBlock, bad_block).serialize())))
+        assert_raises_rpc_error(-25, 'Must submit previous header', lambda: node.submitheader(hexdata=super(CBlock, bad_block).serialize().hex()))
 
         block.nTime += 1
         block.solve()
@@ -193,23 +192,23 @@ class MiningTest(BitcoinTestFramework):
             return {'hash': b_hash, 'height': 202, 'branchlen': branchlen, 'status': status}
 
         assert chain_tip(block.hash) not in node.getchaintips()
-        node.submitheader(hexdata=b2x(block.serialize()))
+        node.submitheader(hexdata=block.serialize().hex())
         assert chain_tip(block.hash) in node.getchaintips()
-        node.submitheader(hexdata=b2x(CBlockHeader(block).serialize()))  # Noop
+        node.submitheader(hexdata=CBlockHeader(block).serialize().hex())  # Noop
         assert chain_tip(block.hash) in node.getchaintips()
 
         bad_block_root = copy.deepcopy(block)
         bad_block_root.hashMerkleRoot += 2
         bad_block_root.solve()
         assert chain_tip(bad_block_root.hash) not in node.getchaintips()
-        node.submitheader(hexdata=b2x(CBlockHeader(bad_block_root).serialize()))
+        node.submitheader(hexdata=CBlockHeader(bad_block_root).serialize().hex())
         assert chain_tip(bad_block_root.hash) in node.getchaintips()
         # Should still reject invalid blocks, even if we have the header:
-        assert_equal(node.submitblock(hexdata=b2x(bad_block_root.serialize())), 'bad-txnmrklroot')
-        assert_equal(node.submitblock(hexdata=b2x(bad_block_root.serialize())), 'bad-txnmrklroot')
+        assert_equal(node.submitblock(hexdata=bad_block_root.serialize().hex()), 'bad-txnmrklroot')
+        assert_equal(node.submitblock(hexdata=bad_block_root.serialize().hex()), 'bad-txnmrklroot')
         assert chain_tip(bad_block_root.hash) in node.getchaintips()
         # We know the header for this invalid block, so should just return early without error:
-        node.submitheader(hexdata=b2x(CBlockHeader(bad_block_root).serialize()))
+        node.submitheader(hexdata=CBlockHeader(bad_block_root).serialize().hex())
         assert chain_tip(bad_block_root.hash) in node.getchaintips()
 
         bad_block_lock = copy.deepcopy(block)
@@ -217,19 +216,19 @@ class MiningTest(BitcoinTestFramework):
         bad_block_lock.vtx[0].rehash()
         bad_block_lock.hashMerkleRoot = bad_block_lock.calc_merkle_root()
         bad_block_lock.solve()
-        assert_equal(node.submitblock(hexdata=b2x(bad_block_lock.serialize())), 'bad-txns-nonfinal')
-        assert_equal(node.submitblock(hexdata=b2x(bad_block_lock.serialize())), 'duplicate-invalid')
+        assert_equal(node.submitblock(hexdata=bad_block_lock.serialize().hex()), 'bad-txns-nonfinal')
+        assert_equal(node.submitblock(hexdata=bad_block_lock.serialize().hex()), 'duplicate-invalid')
         # Build a "good" block on top of the submitted bad block
         bad_block2 = copy.deepcopy(block)
         bad_block2.hashPrevBlock = bad_block_lock.sha256
         bad_block2.solve()
-        assert_raises_rpc_error(-25, 'bad-prevblk', lambda: node.submitheader(hexdata=b2x(CBlockHeader(bad_block2).serialize())))
+        assert_raises_rpc_error(-25, 'bad-prevblk', lambda: node.submitheader(hexdata=CBlockHeader(bad_block2).serialize().hex()))
 
         # Should reject invalid header right away
         bad_block_time = copy.deepcopy(block)
         bad_block_time.nTime = 1
         bad_block_time.solve()
-        assert_raises_rpc_error(-25, 'time-too-old', lambda: node.submitheader(hexdata=b2x(CBlockHeader(bad_block_time).serialize())))
+        assert_raises_rpc_error(-25, 'time-too-old', lambda: node.submitheader(hexdata=CBlockHeader(bad_block_time).serialize().hex()))
 
         # Should ask for the block from a p2p node, if they announce the header as well:
         node.add_p2p_connection(P2PDataStore())
@@ -240,11 +239,11 @@ class MiningTest(BitcoinTestFramework):
 
         # Building a few blocks should give the same results
         node.generatetoaddress(10, node.get_deterministic_priv_key().address)
-        assert_raises_rpc_error(-25, 'time-too-old', lambda: node.submitheader(hexdata=b2x(CBlockHeader(bad_block_time).serialize())))
-        assert_raises_rpc_error(-25, 'bad-prevblk', lambda: node.submitheader(hexdata=b2x(CBlockHeader(bad_block2).serialize())))
-        node.submitheader(hexdata=b2x(CBlockHeader(block).serialize()))
-        node.submitheader(hexdata=b2x(CBlockHeader(bad_block_root).serialize()))
-        assert_equal(node.submitblock(hexdata=b2x(block.serialize())), 'duplicate')  # valid
+        assert_raises_rpc_error(-25, 'time-too-old', lambda: node.submitheader(hexdata=CBlockHeader(bad_block_time).serialize().hex()))
+        assert_raises_rpc_error(-25, 'bad-prevblk', lambda: node.submitheader(hexdata=CBlockHeader(bad_block2).serialize().hex()))
+        node.submitheader(hexdata=CBlockHeader(block).serialize().hex())
+        node.submitheader(hexdata=CBlockHeader(bad_block_root).serialize().hex())
+        assert_equal(node.submitblock(hexdata=block.serialize().hex()), 'duplicate')  # valid
 
 
 if __name__ == '__main__':
diff --git a/test/functional/p2p_segwit.py b/test/functional/p2p_segwit.py
index 8f8e89cf15..14ebd297fc 100755
--- a/test/functional/p2p_segwit.py
+++ b/test/functional/p2p_segwit.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.
 """Test segwit transactions and blocks on P2P network."""
-from binascii import hexlify
 import math
 import random
 import struct
@@ -74,7 +73,6 @@ from test_framework.script import (
 from test_framework.test_framework import BitcoinTestFramework
 from test_framework.util import (
     assert_equal,
-    bytes_to_hex_str,
     connect_nodes,
     disconnect_nodes,
     get_bip9_status,
@@ -566,7 +564,7 @@ class SegWitTest(BitcoinTestFramework):
                 witness_root = CBlock.get_merkle_root([ser_uint256(0),
                                                        ser_uint256(txid)])
                 script = get_witness_script(witness_root, 0)
-                assert_equal(witness_commitment, bytes_to_hex_str(script))
+                assert_equal(witness_commitment, script.hex())
 
     @subtest
     def advance_to_segwit_lockin(self):
@@ -686,13 +684,13 @@ class SegWitTest(BitcoinTestFramework):
         if self.segwit_status != 'active':
             # Just check mempool acceptance, but don't add the transaction to the mempool, since witness is disallowed
             # in blocks and the tx is impossible to mine right now.
-            assert_equal(self.nodes[0].testmempoolaccept([bytes_to_hex_str(tx3.serialize_with_witness())]), [{'txid': tx3.hash, 'allowed': True}])
+            assert_equal(self.nodes[0].testmempoolaccept([tx3.serialize_with_witness().hex()]), [{'txid': tx3.hash, 'allowed': True}])
             # Create the same output as tx3, but by replacing tx
             tx3_out = tx3.vout[0]
             tx3 = tx
             tx3.vout = [tx3_out]
             tx3.rehash()
-            assert_equal(self.nodes[0].testmempoolaccept([bytes_to_hex_str(tx3.serialize_with_witness())]), [{'txid': tx3.hash, 'allowed': True}])
+            assert_equal(self.nodes[0].testmempoolaccept([tx3.serialize_with_witness().hex()]), [{'txid': tx3.hash, 'allowed': True}])
         test_transaction_acceptance(self.nodes[0], self.test_node, tx3, with_witness=True, accepted=True)
 
         self.nodes[0].generate(1)
@@ -885,13 +883,13 @@ class SegWitTest(BitcoinTestFramework):
 
         # We can't send over the p2p network, because this is too big to relay
         # TODO: repeat this test with a block that can be relayed
-        self.nodes[0].submitblock(bytes_to_hex_str(block.serialize(True)))
+        self.nodes[0].submitblock(block.serialize(True).hex())
 
         assert(self.nodes[0].getbestblockhash() != block.hash)
 
         block.vtx[0].wit.vtxinwit[0].scriptWitness.stack.pop()
         assert(get_virtual_size(block) < MAX_BLOCK_BASE_SIZE)
-        self.nodes[0].submitblock(bytes_to_hex_str(block.serialize(True)))
+        self.nodes[0].submitblock(block.serialize(True).hex())
 
         assert(self.nodes[0].getbestblockhash() == block.hash)
 
@@ -998,14 +996,14 @@ class SegWitTest(BitcoinTestFramework):
         add_witness_commitment(block, nonce=1)
         block.vtx[0].wit = CTxWitness()  # drop the nonce
         block.solve()
-        self.nodes[0].submitblock(bytes_to_hex_str(block.serialize(True)))
+        self.nodes[0].submitblock(block.serialize(True).hex())
         assert(self.nodes[0].getbestblockhash() != block.hash)
 
         # Now redo commitment with the standard nonce, but let bitcoind fill it in.
         add_witness_commitment(block, nonce=0)
         block.vtx[0].wit = CTxWitness()
         block.solve()
-        self.nodes[0].submitblock(bytes_to_hex_str(block.serialize(True)))
+        self.nodes[0].submitblock(block.serialize(True).hex())
         assert_equal(self.nodes[0].getbestblockhash(), block.hash)
 
         # This time, add a tx with non-empty witness, but don't supply
@@ -1020,7 +1018,7 @@ class SegWitTest(BitcoinTestFramework):
         block_2.vtx[0].vout.pop()
         block_2.vtx[0].wit = CTxWitness()
 
-        self.nodes[0].submitblock(bytes_to_hex_str(block_2.serialize(True)))
+        self.nodes[0].submitblock(block_2.serialize(True).hex())
         # Tip should not advance!
         assert(self.nodes[0].getbestblockhash() != block_2.hash)
 
@@ -1347,7 +1345,7 @@ class SegWitTest(BitcoinTestFramework):
         assert_equal(raw_tx["vsize"], vsize)
         assert_equal(raw_tx["weight"], weight)
         assert_equal(len(raw_tx["vin"][0]["txinwitness"]), 1)
-        assert_equal(raw_tx["vin"][0]["txinwitness"][0], hexlify(witness_program).decode('ascii'))
+        assert_equal(raw_tx["vin"][0]["txinwitness"][0], witness_program.hex())
         assert(vsize != raw_tx["size"])
 
         # Cleanup: mine the transactions and update utxo for next test
diff --git a/test/functional/rpc_decodescript.py b/test/functional/rpc_decodescript.py
index 940386eee7..fbd273ab00 100755
--- a/test/functional/rpc_decodescript.py
+++ b/test/functional/rpc_decodescript.py
@@ -6,7 +6,7 @@
 
 from test_framework.messages import CTransaction, sha256
 from test_framework.test_framework import BitcoinTestFramework
-from test_framework.util import assert_equal, bytes_to_hex_str, hex_str_to_bytes
+from test_framework.util import assert_equal, hex_str_to_bytes
 
 from io import BytesIO
 
@@ -81,7 +81,7 @@ class DecodeScriptTest(BitcoinTestFramework):
         rpc_result = self.nodes[0].decodescript(multisig_script)
         assert_equal('2 ' + public_key + ' ' + public_key + ' ' + public_key +  ' 3 OP_CHECKMULTISIG', rpc_result['asm'])
         # multisig in P2WSH
-        multisig_script_hash = bytes_to_hex_str(sha256(hex_str_to_bytes(multisig_script)))
+        multisig_script_hash = sha256(hex_str_to_bytes(multisig_script)).hex()
         assert_equal('0 ' + multisig_script_hash, rpc_result['segwit']['asm'])
 
         # 4) P2SH scriptPubKey
@@ -119,7 +119,7 @@ class DecodeScriptTest(BitcoinTestFramework):
         rpc_result = self.nodes[0].decodescript(cltv_script)
         assert_equal('OP_IF ' + public_key + ' OP_CHECKSIGVERIFY OP_ELSE 500000 OP_CHECKLOCKTIMEVERIFY OP_DROP OP_ENDIF ' + public_key + ' OP_CHECKSIG', rpc_result['asm'])
         # CLTV script in P2WSH
-        cltv_script_hash = bytes_to_hex_str(sha256(hex_str_to_bytes(cltv_script)))
+        cltv_script_hash = sha256(hex_str_to_bytes(cltv_script)).hex()
         assert_equal('0 ' + cltv_script_hash, rpc_result['segwit']['asm'])
 
         # 7) P2PK scriptPubKey
@@ -196,7 +196,7 @@ 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 = bytes_to_hex_str(txSave.vin[0].scriptSig)[2:(0x48*2+4)]
+        push_signature = txSave.vin[0].scriptSig.hex()[2:(0x48*2+4)]
         signature = push_signature[2:]
         der_signature = signature[:-2]
         signature_sighash_decoded = der_signature + '[ALL]'
@@ -206,23 +206,23 @@ class DecodeScriptTest(BitcoinTestFramework):
 
         # 1) P2PK scriptSig
         txSave.vin[0].scriptSig = hex_str_to_bytes(push_signature)
-        rpc_result = self.nodes[0].decoderawtransaction(bytes_to_hex_str(txSave.serialize()))
+        rpc_result = self.nodes[0].decoderawtransaction(txSave.serialize().hex())
         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 = hex_str_to_bytes(push_signature_2)
-        rpc_result = self.nodes[0].decoderawtransaction(bytes_to_hex_str(txSave.serialize()))
+        rpc_result = self.nodes[0].decoderawtransaction(txSave.serialize().hex())
         assert_equal(signature_2_sighash_decoded, rpc_result['vin'][0]['scriptSig']['asm'])
 
         # 2) multisig scriptSig
         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()))
+        rpc_result = self.nodes[0].decoderawtransaction(txSave.serialize().hex())
         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 = hex_str_to_bytes('6a143011020701010101010101020601010101010101')
-        rpc_result = self.nodes[0].decoderawtransaction(bytes_to_hex_str(txSave.serialize()))
+        rpc_result = self.nodes[0].decoderawtransaction(txSave.serialize().hex())
         assert_equal('OP_RETURN 3011020701010101010101020601010101010101', rpc_result['vin'][0]['scriptSig']['asm'])
 
     def run_test(self):
diff --git a/test/functional/rpc_rawtransaction.py b/test/functional/rpc_rawtransaction.py
index c793cf00de..5f9bdb4703 100755
--- a/test/functional/rpc_rawtransaction.py
+++ b/test/functional/rpc_rawtransaction.py
@@ -17,7 +17,7 @@ from decimal import Decimal
 from io import BytesIO
 from test_framework.messages import CTransaction, ToHex
 from test_framework.test_framework import BitcoinTestFramework
-from test_framework.util import assert_equal, assert_raises_rpc_error, bytes_to_hex_str, connect_nodes_bi, hex_str_to_bytes
+from test_framework.util import assert_equal, assert_raises_rpc_error, connect_nodes_bi, hex_str_to_bytes
 
 class multidict(dict):
     """Dictionary that allows duplicate keys.
@@ -119,21 +119,21 @@ class RawTransactionsTest(BitcoinTestFramework):
         tx.deserialize(BytesIO(hex_str_to_bytes(self.nodes[2].createrawtransaction(inputs=[{'txid': txid, 'vout': 9}], outputs={address: 99}))))
         assert_equal(len(tx.vout), 1)
         assert_equal(
-            bytes_to_hex_str(tx.serialize()),
+            tx.serialize().hex(),
             self.nodes[2].createrawtransaction(inputs=[{'txid': txid, 'vout': 9}], outputs=[{address: 99}]),
         )
         # Two outputs
         tx.deserialize(BytesIO(hex_str_to_bytes(self.nodes[2].createrawtransaction(inputs=[{'txid': txid, 'vout': 9}], outputs=OrderedDict([(address, 99), (address2, 99)])))))
         assert_equal(len(tx.vout), 2)
         assert_equal(
-            bytes_to_hex_str(tx.serialize()),
+            tx.serialize().hex(),
             self.nodes[2].createrawtransaction(inputs=[{'txid': txid, 'vout': 9}], outputs=[{address: 99}, {address2: 99}]),
         )
         # Multiple mixed outputs
         tx.deserialize(BytesIO(hex_str_to_bytes(self.nodes[2].createrawtransaction(inputs=[{'txid': txid, 'vout': 9}], outputs=multidict([(address, 99), (address2, 99), ('data', '99')])))))
         assert_equal(len(tx.vout), 3)
         assert_equal(
-            bytes_to_hex_str(tx.serialize()),
+            tx.serialize().hex(),
             self.nodes[2].createrawtransaction(inputs=[{'txid': txid, 'vout': 9}], outputs=[{address: 99}, {address2: 99}, {'data': '99'}]),
         )
 
diff --git a/test/functional/rpc_signrawtransaction.py b/test/functional/rpc_signrawtransaction.py
index 56e2c73a90..e603b5cb4f 100755
--- a/test/functional/rpc_signrawtransaction.py
+++ b/test/functional/rpc_signrawtransaction.py
@@ -5,7 +5,7 @@
 """Test transaction signing using the signrawtransaction* RPCs."""
 
 from test_framework.test_framework import BitcoinTestFramework
-from test_framework.util import assert_equal, assert_raises_rpc_error, bytes_to_hex_str, hex_str_to_bytes
+from test_framework.util import assert_equal, assert_raises_rpc_error, hex_str_to_bytes
 from test_framework.messages import sha256
 from test_framework.script import CScript, OP_0
 
@@ -161,7 +161,7 @@ class SignRawTransactionsTest(BitcoinTestFramework):
         unspent_output = self.nodes[1].listunspent(0, 999999, [p2sh_p2wsh_address["address"]])[0]
         assert_equal(unspent_output["witnessScript"], p2sh_p2wsh_address["redeemScript"])
         p2sh_redeemScript = CScript([OP_0, sha256(hex_str_to_bytes(p2sh_p2wsh_address["redeemScript"]))])
-        assert_equal(unspent_output["redeemScript"], bytes_to_hex_str(p2sh_redeemScript))
+        assert_equal(unspent_output["redeemScript"], p2sh_redeemScript.hex())
         # Now create and sign a transaction spending that output on node[0], which doesn't know the scripts or keys
         spending_tx = self.nodes[0].createrawtransaction([unspent_output], {self.nodes[1].getnewaddress(): Decimal("49.998")})
         spending_tx_signed = self.nodes[0].signrawtransactionwithkey(spending_tx, [embedded_privkey], [unspent_output])
diff --git a/test/functional/test_framework/address.py b/test/functional/test_framework/address.py
index 456d43aa2e..0ebc5efb7e 100644
--- a/test/functional/test_framework/address.py
+++ b/test/functional/test_framework/address.py
@@ -5,7 +5,7 @@
 """Encode and decode BASE58, P2PKH and P2SH addresses."""
 
 from .script import hash256, hash160, sha256, CScript, OP_0
-from .util import bytes_to_hex_str, hex_str_to_bytes
+from .util import hex_str_to_bytes
 
 from . import segwit_addr
 
@@ -16,9 +16,9 @@ chars = '123456789ABCDEFGHJKLMNPQRSTUVWXYZabcdefghijkmnopqrstuvwxyz'
 
 def byte_to_base58(b, version):
     result = ''
-    str = bytes_to_hex_str(b)
-    str = bytes_to_hex_str(chr(version).encode('latin-1')) + str
-    checksum = bytes_to_hex_str(hash256(hex_str_to_bytes(str)))
+    str = b.hex()
+    str = chr(version).encode('latin-1').hex() + str
+    checksum = hash256(hex_str_to_bytes(str)).hex()
     str += checksum[:8]
     value = int('0x'+str,0)
     while value > 0:
diff --git a/test/functional/test_framework/blocktools.py b/test/functional/test_framework/blocktools.py
index 15f4502994..9d7b4b2702 100644
--- a/test/functional/test_framework/blocktools.py
+++ b/test/functional/test_framework/blocktools.py
@@ -20,7 +20,6 @@ from .messages import (
     CTxOut,
     FromHex,
     ToHex,
-    bytes_to_hex_str,
     hash256,
     hex_str_to_bytes,
     ser_string,
@@ -190,7 +189,7 @@ def witness_script(use_p2wsh, pubkey):
         witness_program = CScript([OP_1, hex_str_to_bytes(pubkey), OP_1, OP_CHECKMULTISIG])
         scripthash = sha256(witness_program)
         pkscript = CScript([OP_0, scripthash])
-    return bytes_to_hex_str(pkscript)
+    return pkscript.hex()
 
 def create_witness_tx(node, use_p2wsh, utxo, pubkey, encode_p2sh, amount):
     """Return a transaction (in hex) that spends the given utxo to a segwit output.
diff --git a/test/functional/test_framework/messages.py b/test/functional/test_framework/messages.py
index 4bd58519c5..3413a94f7e 100755
--- a/test/functional/test_framework/messages.py
+++ b/test/functional/test_framework/messages.py
@@ -28,7 +28,7 @@ import struct
 import time
 
 from test_framework.siphash import siphash256
-from test_framework.util import hex_str_to_bytes, bytes_to_hex_str, assert_equal
+from test_framework.util import hex_str_to_bytes, assert_equal
 
 MIN_VERSION_SUPPORTED = 60001
 MY_VERSION = 70014  # past bip-31 for ping/pong
@@ -181,7 +181,7 @@ def FromHex(obj, hex_string):
 
 # Convert a binary-serializable object to hex (eg for submission via RPC)
 def ToHex(obj):
-    return bytes_to_hex_str(obj.serialize())
+    return obj.serialize().hex()
 
 # Objects that map to bitcoind objects, which can be serialized/deserialized
 
@@ -319,7 +319,7 @@ class CTxIn:
 
     def __repr__(self):
         return "CTxIn(prevout=%s scriptSig=%s nSequence=%i)" \
-            % (repr(self.prevout), bytes_to_hex_str(self.scriptSig),
+            % (repr(self.prevout), self.scriptSig.hex(),
                self.nSequence)
 
 
@@ -343,7 +343,7 @@ class CTxOut:
     def __repr__(self):
         return "CTxOut(nValue=%i.%08i scriptPubKey=%s)" \
             % (self.nValue // COIN, self.nValue % COIN,
-               bytes_to_hex_str(self.scriptPubKey))
+               self.scriptPubKey.hex())
 
 
 class CScriptWitness:
@@ -355,7 +355,7 @@ class CScriptWitness:
 
     def __repr__(self):
         return "CScriptWitness(%s)" % \
-               (",".join([bytes_to_hex_str(x) for x in self.stack]))
+               (",".join([x.hex() for x in self.stack]))
 
     def is_null(self):
         if self.stack:
diff --git a/test/functional/test_framework/netutil.py b/test/functional/test_framework/netutil.py
index 45c182f630..1a3efcd1ac 100644
--- a/test/functional/test_framework/netutil.py
+++ b/test/functional/test_framework/netutil.py
@@ -12,7 +12,7 @@ import socket
 import struct
 import array
 import os
-from binascii import unhexlify, hexlify
+from binascii import unhexlify
 
 # STATE_ESTABLISHED = '01'
 # STATE_SYN_SENT  = '02'
@@ -139,7 +139,7 @@ def addr_to_hex(addr):
         addr = sub[0] + ([0] * nullbytes) + sub[1]
     else:
         raise ValueError('Could not parse address %s' % addr)
-    return hexlify(bytearray(addr)).decode('ascii')
+    return bytearray(addr).hex()
 
 def test_ipv6_local():
     '''
diff --git a/test/functional/test_framework/script.py b/test/functional/test_framework/script.py
index 012c80a1be..f7df7d23f5 100644
--- a/test/functional/test_framework/script.py
+++ b/test/functional/test_framework/script.py
@@ -9,7 +9,6 @@ This file is modified from python-bitcoinlib.
 
 from .messages import CTransaction, CTxOut, sha256, hash256, uint256_from_str, ser_uint256, ser_string
 
-from binascii import hexlify
 import hashlib
 import struct
 
@@ -452,7 +451,7 @@ class CScript(bytes):
 
     # Python 3.4 compatibility
     def hex(self):
-        return hexlify(self).decode('ascii')
+        return self.hex()
 
     def __new__(cls, value=b''):
         if isinstance(value, bytes) or isinstance(value, bytearray):
@@ -545,7 +544,7 @@ class CScript(bytes):
     def __repr__(self):
         def _repr(o):
             if isinstance(o, bytes):
-                return "x('%s')" % hexlify(o).decode('ascii')
+                return "x('%s')" % o.hex()
             else:
                 return repr(o)
 
diff --git a/test/functional/test_framework/util.py b/test/functional/test_framework/util.py
index fef9982412..fb2ee8e90c 100644
--- a/test/functional/test_framework/util.py
+++ b/test/functional/test_framework/util.py
@@ -5,7 +5,7 @@
 """Helpful routines for regression testing."""
 
 from base64 import b64encode
-from binascii import hexlify, unhexlify
+from binascii import unhexlify
 from decimal import Decimal, ROUND_DOWN
 import hashlib
 import inspect
@@ -182,8 +182,8 @@ 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 b_2_x(byte_str):
+    return byte_str.hex()
 
 def hash256(byte_str):
     sha256 = hashlib.sha256()
diff --git a/test/functional/wallet_bumpfee.py b/test/functional/wallet_bumpfee.py
index 7d3d9b61e2..67af495023 100755
--- a/test/functional/wallet_bumpfee.py
+++ b/test/functional/wallet_bumpfee.py
@@ -19,7 +19,7 @@ import io
 from test_framework.blocktools import add_witness_commitment, create_block, create_coinbase, send_to_witness
 from test_framework.messages import BIP125_SEQUENCE_NUMBER, CTransaction
 from test_framework.test_framework import BitcoinTestFramework
-from test_framework.util import assert_equal, assert_greater_than, assert_raises_rpc_error, bytes_to_hex_str, connect_nodes_bi, hex_str_to_bytes, sync_mempools
+from test_framework.util import assert_equal, assert_greater_than, assert_raises_rpc_error, connect_nodes_bi, hex_str_to_bytes, sync_mempools
 
 WALLET_PASSPHRASE = "test"
 WALLET_PASSPHRASE_TIMEOUT = 3600
@@ -298,7 +298,7 @@ def submit_block_with_tx(node, tx):
     block.hashMerkleRoot = block.calc_merkle_root()
     add_witness_commitment(block)
     block.solve()
-    node.submitblock(bytes_to_hex_str(block.serialize(True)))
+    node.submitblock(block.serialize(True).hex())
     return block
 
 
diff --git a/test/functional/wallet_importmulti.py b/test/functional/wallet_importmulti.py
index c6d0425f22..e6c01e99e9 100755
--- a/test/functional/wallet_importmulti.py
+++ b/test/functional/wallet_importmulti.py
@@ -25,7 +25,6 @@ from test_framework.util import (
     assert_equal,
     assert_greater_than,
     assert_raises_rpc_error,
-    bytes_to_hex_str,
 )
 from test_framework.wallet_util import (
     get_key,
@@ -127,7 +126,7 @@ class ImportMultiTest(BitcoinTestFramework):
 
         # Nonstandard scriptPubKey + !internal
         self.log.info("Should not import a nonstandard scriptPubKey without internal flag")
-        nonstandardScriptPubKey = key.p2pkh_script + bytes_to_hex_str(CScript([OP_NOP]))
+        nonstandardScriptPubKey = key.p2pkh_script + CScript([OP_NOP]).hex()
         key = get_key(self.nodes[0])
         self.test_importmulti({"scriptPubKey": nonstandardScriptPubKey,
                                "timestamp": "now"},
diff --git a/test/functional/wallet_listtransactions.py b/test/functional/wallet_listtransactions.py
index 17f044bf65..ce76d06d2b 100755
--- a/test/functional/wallet_listtransactions.py
+++ b/test/functional/wallet_listtransactions.py
@@ -11,7 +11,6 @@ from test_framework.test_framework import BitcoinTestFramework
 from test_framework.util import (
     assert_array_result,
     assert_equal,
-    bytes_to_hex_str,
     hex_str_to_bytes,
     sync_mempools,
 )
@@ -158,7 +157,7 @@ class ListTransactionsTest(BitcoinTestFramework):
         tx3 = self.nodes[0].createrawtransaction(inputs, outputs)
         tx3_modified = tx_from_hex(tx3)
         tx3_modified.vin[0].nSequence = 0
-        tx3 = bytes_to_hex_str(tx3_modified.serialize())
+        tx3 = tx3_modified.serialize().hex()
         tx3_signed = self.nodes[0].signrawtransactionwithwallet(tx3)['hex']
         txid_3 = self.nodes[0].sendrawtransaction(tx3_signed)
 
@@ -184,7 +183,7 @@ class ListTransactionsTest(BitcoinTestFramework):
         # Replace tx3, and check that tx4 becomes unknown
         tx3_b = tx3_modified
         tx3_b.vout[0].nValue -= int(Decimal("0.004") * COIN)  # bump the fee
-        tx3_b = bytes_to_hex_str(tx3_b.serialize())
+        tx3_b = tx3_b.serialize().hex()
         tx3_b_signed = self.nodes[0].signrawtransactionwithwallet(tx3_b)['hex']
         txid_3b = self.nodes[0].sendrawtransaction(tx3_b_signed, True)
         assert(is_opt_in(self.nodes[0], txid_3b))
diff --git a/test/functional/wallet_txn_clone.py b/test/functional/wallet_txn_clone.py
index a0a35bf43d..2f927502ff 100755
--- a/test/functional/wallet_txn_clone.py
+++ b/test/functional/wallet_txn_clone.py
@@ -8,7 +8,6 @@ import io
 from test_framework.test_framework import BitcoinTestFramework
 from test_framework.util import (
     assert_equal,
-    bytes_to_hex_str as b2x,
     connect_nodes,
     disconnect_nodes,
     sync_blocks,
@@ -82,7 +81,7 @@ class TxnMallTest(BitcoinTestFramework):
 
         # Use a different signature hash type to sign.  This creates an equivalent but malleated clone.
         # Don't send the clone anywhere yet
-        tx1_clone = self.nodes[0].signrawtransactionwithwallet(b2x(clone_tx.serialize()), None, "ALL|ANYONECANPAY")
+        tx1_clone = self.nodes[0].signrawtransactionwithwallet(clone_tx.serialize().hex(), None, "ALL|ANYONECANPAY")
         assert_equal(tx1_clone["complete"], True)
 
         # Have node0 mine a block, if requested:
diff --git a/test/lint/lint-python-dead-code.sh b/test/lint/lint-python-dead-code.sh
index 863caa9d5c..2ec7574718 100755
--- a/test/lint/lint-python-dead-code.sh
+++ b/test/lint/lint-python-dead-code.sh
@@ -15,5 +15,5 @@ fi
 
 vulture \
     --min-confidence 60 \
-    --ignore-names "argtypes,connection_lost,connection_made,converter,data_received,daemon,errcheck,get_ecdh_key,get_privkey,is_compressed,is_fullyvalid,msg_generic,on_*,optionxform,restype,set_privkey,profile_with_perf" \
+    --ignore-names "b_2_x,argtypes,connection_lost,connection_made,converter,data_received,daemon,errcheck,get_ecdh_key,get_privkey,is_compressed,is_fullyvalid,msg_generic,on_*,optionxform,restype,set_privkey,profile_with_perf" \
     $(git ls-files -- "*.py" ":(exclude)contrib/" ":(exclude)test/functional/data/invalid_txs.py")