nitpicks

respdiff/dbhelper.py

 from abc import ABC
 from contextlib import contextmanager
-import logging
 import os
 import struct
 import sys
@@ -160,6 +159,8 @@ class DNSReply:
     def __eq__(self, other) -> bool:
         if self.timeout and other.timeout:
             return True
+        # float equality comparison: use 10^-7 tolerance since it's less than available
+        # resoltuion from the time_int integer value (which is 10^-6)
         return self.wire == other.wire and \
             abs(self.time - other.time) < 10 ** -7
 
@@ -169,13 +170,14 @@ class DNSReply:
             return self.TIMEOUT_INT
         value = round(self.time * (10 ** 6))
         if value > self.TIMEOUT_INT:
-            raise ValueError('Maximum time value exceeded')
+            raise ValueError(
+                'Maximum time value exceeded: (value: "{}", max: {})'.format(
+                    value, self.TIMEOUT_INT))
         return value
 
     @property
     def binary(self) -> bytes:
         length = len(self.wire)
-        assert length < 2**(self.SIZEOF_SHORT*8), 'Maximum wire format length exceeded'
         return struct.pack('<I', self.time_int) + struct.pack('<H', length) + self.wire
 
     @classmethod
@@ -215,10 +217,12 @@ class DNSRepliesFactory:
             reply, buff = DNSReply.from_binary(buff)
             replies[server] = reply
         if buff:
-            logging.warning('Trailing data in buffer')
+            raise ValueError('Trailing data in buffer')
         return replies
 
     def serialize(self, replies: Mapping[ResolverID, DNSReply]) -> bytes:
+        if len(replies) > len(self.servers):
+            raise ValueError('Extra unexpected data to serialize!')
         data = []
         for server in self.servers:
             try:
@@ -227,8 +231,6 @@ class DNSRepliesFactory:
                 raise ValueError('Missing reply for server "{}"!'.format(server))
             else:
                 data.append(reply.binary)
-        if len(replies) > len(self.servers):
-            raise ValueError('Extra unexpected data to serialize!')
         return b''.join(data)
 
 

respdiff/histogram.py

 #!/usr/bin/env python3
 
+# NOTE: Due to a weird bug, numpy is detected as a 3rd party module, while lmdb
+#       is not and pylint complains about wrong-import-order.
+#       Since these checks have to be disabled for matplotlib imports anyway, they
+#       were moved a bit higher up to avoid the issue.
 # pylint: disable=wrong-import-order,wrong-import-position
 import argparse
 import logging

respdiff/msgdiff.py

@@ -259,7 +259,8 @@ def export_json(filename: str, report: DiffReport):
                     for field, mismatch in diff.items():
                         report.target_disagreements.add_mismatch(field, mismatch, qid)
 
-    # it doesn't make sense to use existing report.json
+    # NOTE: msgdiff is the first tool in the toolchain to generate report.json
+    #       thus it doesn't make sense to re-use existing report.json file
     if os.path.exists(filename):
         backup_filename = filename + '.bak'
         os.rename(filename, backup_filename)
@@ -321,9 +322,10 @@ def main():
         qid_stream = lmdb.key_stream(LMDB.ANSWERS)
 
         dnsreplies_factory = DNSRepliesFactory(servers)
-        func = partial(compare_lmdb_wrapper, criteria, target, dnsreplies_factory)
+        compare_func = partial(
+            compare_lmdb_wrapper, criteria, target, dnsreplies_factory)
         with pool.Pool() as p:
-            for _ in p.imap_unordered(func, qid_stream, chunksize=10):
+            for _ in p.imap_unordered(compare_func, qid_stream, chunksize=10):
                 pass
         export_json(datafile, report)
 

tests/test_dbhelper.py

@@ -46,7 +46,7 @@ def test_dns_reply_time_int(time, time_int):
     assert reply.time_int == time_int
 
 
-DR_TIMEOUT = DNSReply(None, None)
+DR_TIMEOUT = DNSReply(None)
 DR_TIMEOUT_BIN = b'\xff\xff\xff\xff\x00\x00'
 DR_EMPTY_0 = DNSReply(b'')
 DR_EMPTY_0_BIN = b'\x00\x00\x00\x00\x00\x00'