Merge bitcoin/bitcoin#22619: test: refactor: use consistent bytes <-> hex-string conversion in functional test framework

5a1bef60a0 test: refactor: remove binascii from test_framework (Zero-1729)

Pull request description:

  This PR continues the work started in PR #22593, regarding using the `bytes` built-in module. In this PR specifically, instances of `binascii`'s methods `hexlify`, `unhexlify`,  and `a2b_hex` have been replaced with the build-in `bytes` module's `hex` and `fromhex` methods where appropriate to make bytes <-> hex-string conversions consistent across the functional test files and test_framework.

  Additionally, certain changes made are based on the following assumption:

  ```
  bytes.hex(data) == binascii.hexlify(data).decode()
  bytes.hex(data).encode() == binascii.hexlify(data)
  ```

  Ran the functional tests to ensure behaviour is still consistent and changes didn't break existing tests.

  closes #22605

ACKs for top commit:
  theStack:
    Code-review ACK 5a1bef60a0 🔢

Tree-SHA512: 8f28076cf0580a0d02a156f3e1e94c9badd3d41c3fbdfb2b87cd8a761dde2c94faa5f4c448d6747b1ccc9111c3ef1a1d7b42a11c806b241fa0410b7529e2445f

test/functional/interface_rest.py

@@ -4,7 +4,6 @@
 # file COPYING or http://www.opensource.org/licenses/mit-license.php.
 """Test the REST API."""
 
-import binascii
 from decimal import Decimal
 from enum import Enum
 from io import BytesIO
@@ -235,13 +234,13 @@ class RESTTest (BitcoinTestFramework):
         response_hex = self.test_rest_request("/block/{}".format(bb_hash), req_type=ReqType.HEX, ret_type=RetType.OBJ)
         assert_greater_than(int(response_hex.getheader('content-length')), BLOCK_HEADER_SIZE*2)
         response_hex_bytes = response_hex.read().strip(b'\n')
-        assert_equal(binascii.hexlify(response_bytes), response_hex_bytes)
+        assert_equal(response_bytes.hex().encode(), response_hex_bytes)
 
         # Compare with hex block header
         response_header_hex = self.test_rest_request("/headers/1/{}".format(bb_hash), req_type=ReqType.HEX, ret_type=RetType.OBJ)
         assert_greater_than(int(response_header_hex.getheader('content-length')), BLOCK_HEADER_SIZE*2)
         response_header_hex_bytes = response_header_hex.read(BLOCK_HEADER_SIZE*2)
-        assert_equal(binascii.hexlify(response_bytes[:BLOCK_HEADER_SIZE]), response_header_hex_bytes)
+        assert_equal(response_bytes[:BLOCK_HEADER_SIZE].hex().encode(), response_header_hex_bytes)
 
         # Check json format
         block_json_obj = self.test_rest_request("/block/{}".format(bb_hash))

test/functional/rpc_createmultisig.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 multisig RPCs"""
-import binascii
 import decimal
 import itertools
 import json
@@ -66,9 +65,9 @@ class RpcCreateMultiSigTest(BitcoinTestFramework):
 
         # decompress pk2
         pk_obj = ECPubKey()
-        pk_obj.set(binascii.unhexlify(pk2))
+        pk_obj.set(bytes.fromhex(pk2))
         pk_obj.compressed = False
-        pk2 = binascii.hexlify(pk_obj.get_bytes()).decode()
+        pk2 = pk_obj.get_bytes().hex()
 
         node0.createwallet(wallet_name='wmulti0', disable_private_keys=True)
         wmulti0 = node0.get_wallet_rpc('wmulti0')

test/functional/test_framework/bdb.py

@@ -24,7 +24,6 @@ transactions.
 `db_dump -da wallet.dat` is useful to see the data in a wallet.dat BDB file
 """
 
-import binascii
 import struct
 
 # Important constants
@@ -96,7 +95,7 @@ def dump_meta_page(page):
     metadata['key_count'] = key_count
     metadata['record_count'] = record_count
     metadata['flags'] = flags
-    metadata['uid'] = binascii.hexlify(uid)
+    metadata['uid'] = uid.hex().encode()
 
     assert magic == BTREE_MAGIC, 'bdb magic does not match bdb btree magic'
     assert pg_type == BTREE_META, 'Metadata page is not a btree metadata page'
@@ -110,8 +109,9 @@ def dump_meta_page(page):
     metadata['re_pad'] = re_pad
     metadata['root'] = root
     metadata['crypto_magic'] = crypto_magic
-    metadata['iv'] = binascii.hexlify(iv)
-    metadata['chksum'] = binascii.hexlify(chksum)
+    metadata['iv'] = iv.hex().encode()
+    metadata['chksum'] = chksum.hex().encode()
+
     return metadata
 
 # Given the dict from dump_leaf_page, get the key-value pairs and put them into a dict

test/functional/test_framework/blocktools.py

@@ -4,7 +4,6 @@
 # file COPYING or http://www.opensource.org/licenses/mit-license.php.
 """Utilities for manipulating blocks and transactions."""
 
-from binascii import a2b_hex
 import struct
 import time
 import unittest
@@ -74,7 +73,7 @@ def create_block(hashprev=None, coinbase=None, ntime=None, *, version=None, tmpl
     block.nTime = ntime or tmpl.get('curtime') or int(time.time() + 600)
     block.hashPrevBlock = hashprev or int(tmpl['previousblockhash'], 0x10)
     if tmpl and not tmpl.get('bits') is None:
-        block.nBits = struct.unpack('>I', a2b_hex(tmpl['bits']))[0]
+        block.nBits = struct.unpack('>I', bytes.fromhex(tmpl['bits']))[0]
     else:
         block.nBits = 0x207fffff  # difficulty retargeting is disabled in REGTEST chainparams
     if coinbase is None:

test/functional/test_framework/netutil.py

@@ -12,7 +12,6 @@ import socket
 import struct
 import array
 import os
-from binascii import unhexlify
 
 # STATE_ESTABLISHED = '01'
 # STATE_SYN_SENT  = '02'
@@ -44,7 +43,7 @@ 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 = unhexlify(host)
+    host = bytes.fromhex(host)
     host_out = ''
     for x in range(0, len(host) // 4):
         (val,) = struct.unpack('=I', host[x*4:(x+1)*4])