chore: Add py3kwarn to tox

Closes #127

falcon/bench/bench.py

@@ -1,18 +1,20 @@
 #!/usr/bin/env python
 # -*- coding: utf-8 -*-
 
-import sys
+from __future__ import print_function
+
+import argparse
+from collections import defaultdict
+from decimal import Decimal
 import gc
 import random
-import argparse
+import sys
 import timeit
-from decimal import Decimal
-from collections import defaultdict
-
-import create  # NOQA
 
 import falcon.testing as helpers
 
+from falcon.bench import create  # NOQA
+
 
 def avg(array):
     return sum(array) / len(array)

tox.ini

@@ -5,6 +5,10 @@ envlist = py26,py27,py33,pypy,flake8
 deps = -r{toxinidir}/tools/test-requires
 commands = nosetests {posargs}
 
+[testenv:py3kwarn]
+deps = py3kwarn
+commands = py3kwarn falcon
+
 [testenv:flake8]
 commands = flake8 \
            --max-complexity=12 \