https://github.com/gsnedders/python-webencodings/issues/32

--- webencodings-0.5.1.orig/tox.ini
+++ webencodings-0.5.1/tox.ini
@@ -0,0 +1,9 @@
+[pytest]
+python_files=test*.py
+
+[tox]
+envlist = py26, py27, py33, py34, py35, py36, pypy
+
+[testenv]
+deps=pytest
+commands=py.test []