diff --git a/test/functional/interface_rest.py b/test/functional/interface_rest.py
index 6aae98525a..e11660793a 100755
--- a/test/functional/interface_rest.py
+++ b/test/functional/interface_rest.py
@@ -1,430 +1,407 @@
 #!/usr/bin/env python3
 # Copyright (c) 2014-2016 The Bitcoin Core developers
 # Distributed under the MIT software license, see the accompanying
 # file COPYING or http://www.opensource.org/licenses/mit-license.php.
 """Test the REST API."""
 
 from codecs import encode
 from decimal import Decimal
 import http.client
 from io import BytesIO
 import json
 from struct import pack, unpack
 import urllib.parse
 
+from test_framework.messages import deser_uint256
 from test_framework.test_framework import BitcoinTestFramework
 from test_framework.util import (
     assert_equal,
     assert_greater_than,
     connect_nodes_bi,
     hex_str_to_bytes,
 )
 
 
-def deser_uint256(f):
-    r = 0
-    for i in range(8):
-        t = unpack(b"<I", f.read(4))[0]
-        r += t << (i * 32)
-    return r
-
-# allows simple http get calls
-
-
 def http_get_call(host, port, path, response_object=0):
+    """Make a simple HTTP GET request."""
     conn = http.client.HTTPConnection(host, port)
     conn.request('GET', path)
 
     if response_object:
         return conn.getresponse()
 
     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):
+    """Make a simple HTTP POST request with a request body."""
     conn = http.client.HTTPConnection(host, port)
     conn.request('POST', path, requestdata)
 
     if response_object:
         return conn.getresponse()
 
     return conn.getresponse().read()
 
 
 class RESTTest (BitcoinTestFramework):
     FORMAT_SEPARATOR = "."
 
     def set_test_params(self):
         self.setup_clean_chain = True
         self.num_nodes = 3
         self.extra_args = [["-rest"]] * self.num_nodes
 
     def setup_network(self, split=False):
         super().setup_network()
         connect_nodes_bi(self.nodes[0], self.nodes[2])
 
     def run_test(self):
         url = urllib.parse.urlparse(self.nodes[0].url)
         self.log.info("Mining blocks...")
 
         self.nodes[0].generate(1)
         self.sync_all()
         self.nodes[2].generate(100)
         self.sync_all()
 
         assert_equal(self.nodes[0].getbalance(), 50)
 
         txid = self.nodes[0].sendtoaddress(self.nodes[1].getnewaddress(), 0.1)
         self.sync_all()
         self.nodes[2].generate(1)
         self.sync_all()
         bb_hash = self.nodes[0].getbestblockhash()
 
+        # Balance now should be 0.1 on node 1
         assert_equal(self.nodes[1].getbalance(), Decimal("0.1"))
-        # balance now should be 0.1 on node 1
 
-        # load the latest 0.1 tx over the REST API
+        # Load the latest 0.1 tx over the REST API
         json_string = http_get_call(
             url.hostname, url.port, '/rest/tx/' + txid + self.FORMAT_SEPARATOR + "json")
         json_obj = json.loads(json_string)
+        # Get the vin to later check for utxo (should be spent by then)
         vintx = json_obj['vin'][0]['txid']
-        # get the vin to later check for utxo (should be spent by then)
-        # get n of 0.1 outpoint
+        # Get n of 0.1 outpoint
         n = 0
         for vout in json_obj['vout']:
             if vout['value'] == 0.1:
                 n = vout['n']
 
         #
         # GETUTXOS: query an unspent outpoint #
         #
         json_request = '/' + txid + '-' + str(n)
         json_string = http_get_call(
             url.hostname, url.port, '/rest/getutxos' + json_request + self.FORMAT_SEPARATOR + 'json')
         json_obj = json.loads(json_string)
 
-        # check chainTip response
+        # Check chainTip response
         assert_equal(json_obj['chaintipHash'], bb_hash)
 
-        # make sure there is one utxo
+        # Make sure there is one utxo
         assert_equal(len(json_obj['utxos']), 1)
         assert_equal(json_obj['utxos'][0]['value'], 0.1)
 
         #
         # GETUTXOS: now query an already spent outpoint #
         #
         json_request = '/' + vintx + '-0'
         json_string = http_get_call(
             url.hostname, url.port, '/rest/getutxos' + json_request + self.FORMAT_SEPARATOR + 'json')
         json_obj = json.loads(json_string)
 
-        # check chainTip response
+        # Check chainTip response
         assert_equal(json_obj['chaintipHash'], bb_hash)
 
-        # make sure there is no utox in the response because this oupoint has
+        # Make sure there is no utox in the response because this oupoint has
         # been spent
         assert_equal(len(json_obj['utxos']), 0)
 
-        # check bitmap
+        # Check bitmap
         assert_equal(json_obj['bitmap'], "0")
 
         #
         # GETUTXOS: now check both with the same request #
         #
         json_request = '/' + txid + '-' + str(n) + '/' + vintx + '-0'
         json_string = http_get_call(
             url.hostname, url.port, '/rest/getutxos' + json_request + self.FORMAT_SEPARATOR + 'json')
         json_obj = json.loads(json_string)
         assert_equal(len(json_obj['utxos']), 1)
         assert_equal(json_obj['bitmap'], "10")
 
-        # test binary response
+        # Test binary response
         bb_hash = self.nodes[0].getbestblockhash()
 
-        binaryRequest = b'\x01\x02'
-        binaryRequest += hex_str_to_bytes(txid)
-        binaryRequest += pack("i", n)
-        binaryRequest += hex_str_to_bytes(vintx)
-        binaryRequest += pack("i", 0)
+        bin_request = b'\x01\x02'
+        bin_request += hex_str_to_bytes(txid)
+        bin_request += pack("i", n)
+        bin_request += hex_str_to_bytes(vintx)
+        bin_request += pack("i", 0)
 
         bin_response = http_post_call(
-            url.hostname, url.port, '/rest/getutxos' + self.FORMAT_SEPARATOR + 'bin', binaryRequest)
+            url.hostname, url.port, '/rest/getutxos' + self.FORMAT_SEPARATOR + 'bin', bin_request)
         output = BytesIO()
         output.write(bin_response)
         output.seek(0)
-        chainHeight = unpack("i", output.read(4))[0]
-        hashFromBinResponse = hex(deser_uint256(output))[2:].zfill(64)
+        chain_height = unpack("i", output.read(4))[0]
+        response_hash = hex(deser_uint256(output))[2:].zfill(64)
 
-        assert_equal(bb_hash, hashFromBinResponse)
-        # check if getutxo's chaintip during calculation was fine
-        assert_equal(chainHeight, 102)  # chain height must be 102
+        # Check if getutxo's chaintip during calculation was fine
+        assert_equal(bb_hash, response_hash)
+        # Chain height must be 102
+        assert_equal(chain_height, 102)
 
         #
         # GETUTXOS: mempool checks #
         #
 
-        # do a tx and don't sync
+        # Do a tx and don't sync
         txid = self.nodes[0].sendtoaddress(self.nodes[1].getnewaddress(), 0.1)
         json_string = http_get_call(
             url.hostname, url.port, '/rest/tx/' + txid + self.FORMAT_SEPARATOR + "json")
         json_obj = json.loads(json_string)
-        # get the spent output to later check for utxo (should be spent by then)
+        # Get the spent output to later check for utxo (should be spent by then)
         spent = '{}-{}'.format(json_obj['vin'][0]
                                ['txid'], json_obj['vin'][0]['vout'])
-        # get n of 0.1 outpoint
+        # Get n of 0.1 outpoint
         n = 0
         for vout in json_obj['vout']:
             if vout['value'] == 0.1:
                 n = vout['n']
         spending = '{}-{}'.format(txid, n)
 
         json_request = '/' + spending
         json_string = http_get_call(
             url.hostname, url.port, '/rest/getutxos' + json_request + self.FORMAT_SEPARATOR + 'json')
         json_obj = json.loads(json_string)
-        # there should be no outpoint because it has just added to
+        # There should be no outpoint because it has just added to
         # the mempool
         assert_equal(len(json_obj['utxos']), 0)
 
         json_request = '/checkmempool/' + spending
         json_string = http_get_call(
             url.hostname, url.port, '/rest/getutxos' + json_request + self.FORMAT_SEPARATOR + 'json')
         json_obj = json.loads(json_string)
-        # there should be an outpoint because it has just added to
+        # There should be an outpoint because it has just added to
         # the mempool
         assert_equal(len(json_obj['utxos']), 1)
 
         json_request = '/' + spent
         json_string = http_get_call(
             url.hostname, url.port, '/rest/getutxos' + json_request + self.FORMAT_SEPARATOR + 'json')
         json_obj = json.loads(json_string)
-        # there should be an outpoint because its spending tx is not confirmed
+        # There should be an outpoint because its spending tx is not confirmed
         assert_equal(len(json_obj['utxos']), 1)
 
         json_request = '/checkmempool/' + spent
         json_string = http_get_call(
             url.hostname, url.port, '/rest/getutxos' + json_request + self.FORMAT_SEPARATOR + 'json')
         json_obj = json.loads(json_string)
-        # there should be no outpoint because it has just spent (by mempool tx)
+        # There should be no outpoint because it has just spent (by mempool tx)
         assert_equal(len(json_obj['utxos']), 0)
 
         self.nodes[0].generate(1)
         self.sync_all()
 
         json_request = '/' + spending
         json_string = http_get_call(
             url.hostname, url.port, '/rest/getutxos' + json_request + self.FORMAT_SEPARATOR + 'json')
         json_obj = json.loads(json_string)
-        # there should be an outpoint because it was mined
+        # There should be an outpoint because it was mined
         assert_equal(len(json_obj['utxos']), 1)
 
         json_request = '/checkmempool/' + spending
         json_string = http_get_call(
             url.hostname, url.port, '/rest/getutxos' + json_request + self.FORMAT_SEPARATOR + 'json')
         json_obj = json.loads(json_string)
-        # there should be an outpoint because it was mined
+        # There should be an outpoint because it was mined
         assert_equal(len(json_obj['utxos']), 1)
 
-        # do some invalid requests
+        # Do some invalid requests
         json_request = '{"checkmempool'
         response = http_post_call(
             url.hostname, url.port, '/rest/getutxos' + self.FORMAT_SEPARATOR + 'json', json_request, True)
-        # must be a 400 because we send an invalid json request
+        # Must be a 400 because we send an invalid json request
         assert_equal(response.status, 400)
 
         json_request = '{"checkmempool'
         response = http_post_call(
             url.hostname, url.port, '/rest/getutxos' + self.FORMAT_SEPARATOR + 'bin', json_request, True)
-        # must be a 400 because we send an invalid bin request
+        # Must be a 400 because we send an invalid bin request
         assert_equal(response.status, 400)
 
         response = http_post_call(
             url.hostname, url.port, '/rest/getutxos/checkmempool' + self.FORMAT_SEPARATOR + 'bin', '', True)
-        # must be a 400 because we send an invalid bin request
+        # Must be a 400 because we send an invalid bin request
         assert_equal(response.status, 400)
 
-        # test limits
+        # Test limits
         json_request = '/checkmempool/'
         for x in range(0, 20):
             json_request += txid + '-' + str(n) + '/'
         json_request = json_request.rstrip("/")
         response = http_post_call(
             url.hostname, url.port, '/rest/getutxos' + json_request + self.FORMAT_SEPARATOR + 'json', '', True)
+        # Must be a 400 because we exceeding the limits
         assert_equal(response.status, 400)
-        # must be a 400 because we exceeding the limits
 
         json_request = '/checkmempool/'
         for x in range(0, 15):
             json_request += txid + '-' + str(n) + '/'
         json_request = json_request.rstrip("/")
         response = http_post_call(
             url.hostname, url.port, '/rest/getutxos' + json_request + self.FORMAT_SEPARATOR + 'json', '', True)
+        # Must be a 200 because we are within the limits
         assert_equal(response.status, 200)
-        # must be a 200 because we are within the limits
 
+        # Generate block to not affect upcoming tests
         self.nodes[0].generate(
-            1)  # generate block to not affect upcoming tests
+            1)
         self.sync_all()
 
         #
         # /rest/block/ #
         #
 
-        # check binary format
+        # Check binary format
         response = http_get_call(
             url.hostname, url.port, '/rest/block/' + bb_hash + self.FORMAT_SEPARATOR + "bin", True)
         assert_equal(response.status, 200)
         assert_greater_than(int(response.getheader('content-length')), 80)
         response_str = response.read()
 
-        # compare with block header
+        # Compare with block header
         response_header = http_get_call(
             url.hostname, url.port, '/rest/headers/1/' + bb_hash + self.FORMAT_SEPARATOR + "bin", True)
         assert_equal(response_header.status, 200)
         assert_equal(int(response_header.getheader('content-length')), 80)
         response_header_str = response_header.read()
         assert_equal(response_str[0:80], response_header_str)
 
-        # check block hex format
+        # Check block hex format
         response_hex = http_get_call(
             url.hostname, url.port, '/rest/block/' + bb_hash + self.FORMAT_SEPARATOR + "hex", True)
         assert_equal(response_hex.status, 200)
         assert_greater_than(int(response_hex.getheader('content-length')), 160)
         response_hex_str = response_hex.read()
         assert_equal(
             encode(response_str, "hex_codec")[0:160], response_hex_str[0:160])
 
-        # compare with hex block header
+        # 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)
         assert_equal(response_header_hex.status, 200)
         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(encode(response_header_str, "hex_codec")[
                      0:160], response_header_hex_str[0:160])
 
-        # check json format
+        # Check json format
         block_json_string = http_get_call(
             url.hostname, url.port, '/rest/block/' + bb_hash + self.FORMAT_SEPARATOR + 'json')
         block_json_obj = json.loads(block_json_string)
         assert_equal(block_json_obj['hash'], bb_hash)
 
-        # compare with json block header
+        # 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().decode('utf-8')
         json_obj = json.loads(response_header_json_str, parse_float=Decimal)
+        # Ensure that there is one header in the json response
         assert_equal(len(json_obj), 1)
-        # ensure that there is one header in the json response
+        # Request/response hash should be the same
         assert_equal(json_obj[0]['hash'], bb_hash)
-        # request/response hash should be the same
 
-        # compare with normal RPC block response
+        # Compare with normal RPC block response
         rpc_block_json = self.nodes[0].getblock(bb_hash)
-        assert_equal(json_obj[0]['hash'],               rpc_block_json['hash'])
-        assert_equal(
-            json_obj[0]['confirmations'],      rpc_block_json['confirmations'])
-        assert_equal(
-            json_obj[0]['height'],             rpc_block_json['height'])
-        assert_equal(
-            json_obj[0]['version'],            rpc_block_json['version'])
-        assert_equal(
-            json_obj[0]['merkleroot'],         rpc_block_json['merkleroot'])
-        assert_equal(json_obj[0]['time'],               rpc_block_json['time'])
-        assert_equal(
-            json_obj[0]['nonce'],              rpc_block_json['nonce'])
-        assert_equal(json_obj[0]['bits'],               rpc_block_json['bits'])
-        assert_equal(
-            json_obj[0]['difficulty'],         rpc_block_json['difficulty'])
-        assert_equal(
-            json_obj[0]['chainwork'],          rpc_block_json['chainwork'])
-        assert_equal(
-            json_obj[0]['previousblockhash'],  rpc_block_json['previousblockhash'])
+        for key in ['hash', 'confirmations', 'height', 'version', 'merkleroot', 'time', 'nonce', 'bits', 'difficulty', 'chainwork', 'previousblockhash']:
+            assert_equal(json_obj[0][key], rpc_block_json[key])
 
-        # see if we can get 5 headers in one response
+        # See if we can get 5 headers in one response
         self.nodes[1].generate(5)
         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().decode('utf-8')
         json_obj = json.loads(response_header_json_str)
-        assert_equal(len(json_obj), 5)  # now we should have 5 header objects
+        # Now we should have 5 header objects
+        assert_equal(len(json_obj), 5)
 
-        # do tx test
+        # Do tx test
         tx_hash = block_json_obj['tx'][0]['txid']
         json_string = http_get_call(
             url.hostname, url.port, '/rest/tx/' + tx_hash + self.FORMAT_SEPARATOR + "json")
         json_obj = json.loads(json_string)
         assert_equal(json_obj['txid'], tx_hash)
 
-        # check hex format response
+        # Check hex format response
         hex_string = http_get_call(
             url.hostname, url.port, '/rest/tx/' + tx_hash + self.FORMAT_SEPARATOR + "hex", True)
         assert_equal(hex_string.status, 200)
         assert_greater_than(int(response.getheader('content-length')), 10)
 
-        # check block tx details
-        # let's make 3 tx and mine them on node 1
+        # Check block tx details
+        # Let's make 3 tx and mine them on node 1
         txs = []
         txs.append(self.nodes[0].sendtoaddress(
             self.nodes[2].getnewaddress(), 11))
         txs.append(self.nodes[0].sendtoaddress(
             self.nodes[2].getnewaddress(), 11))
         txs.append(self.nodes[0].sendtoaddress(
             self.nodes[2].getnewaddress(), 11))
         self.sync_all()
 
-        # check that there are exactly 3 transactions in the TX memory pool
+        # Check that there are exactly 3 transactions in the TX memory pool
         # before generating the block
         json_string = http_get_call(
             url.hostname, url.port, '/rest/mempool/info' + self.FORMAT_SEPARATOR + 'json')
         json_obj = json.loads(json_string)
         assert_equal(json_obj['size'], 3)
-        # the size of the memory pool should be greater than 3x ~100 bytes
+        # The size of the memory pool should be greater than 3x ~100 bytes
         assert_greater_than(json_obj['bytes'], 300)
 
-        # check that there are our submitted transactions in the TX memory pool
+        # Check that there are our submitted transactions in the TX memory pool
         json_string = http_get_call(
             url.hostname, url.port, '/rest/mempool/contents' + self.FORMAT_SEPARATOR + 'json')
         json_obj = json.loads(json_string)
         for i, tx in enumerate(txs):
             assert_equal(tx in json_obj, True)
             assert_equal(json_obj[tx]['spentby'], txs[i + 1:i + 2])
             assert_equal(json_obj[tx]['depends'], txs[i - 1:i])
 
-        # now mine the transactions
+        # Now mine the transactions
         newblockhash = self.nodes[1].generate(1)
         self.sync_all()
 
-        # check if the 3 tx show up in the new block
+        # Check if the 3 tx show up in the new block
         json_string = http_get_call(
             url.hostname, url.port, '/rest/block/' + newblockhash[0] + self.FORMAT_SEPARATOR + 'json')
         json_obj = json.loads(json_string)
         for tx in json_obj['tx']:
             if not 'coinbase' in tx['vin'][0]:  # exclude coinbase
                 assert_equal(tx['txid'] in txs, True)
 
-        # check the same but without tx details
+        # Check the same but without tx details
         json_string = http_get_call(
             url.hostname, url.port, '/rest/block/notxdetails/' + newblockhash[0] + self.FORMAT_SEPARATOR + 'json')
         json_obj = json.loads(json_string)
         for tx in txs:
             assert_equal(tx in json_obj['tx'], True)
 
-        # test rest bestblock
+        # Test rest bestblock
         bb_hash = self.nodes[0].getbestblockhash()
 
         json_string = http_get_call(
             url.hostname, url.port, '/rest/chaininfo.json')
         json_obj = json.loads(json_string)
         assert_equal(json_obj['bestblockhash'], bb_hash)
 
 
 if __name__ == '__main__':
     RESTTest().main()