diff --git a/tox.ini b/tox.ini
index cdf47bb00c9..74cec50a26e 100644
--- a/tox.ini
+++ b/tox.ini
@@ -20,7 +20,9 @@ basepython = python3
 
 [testenv]
 usedevelop = true
-passenv = DJANGO_SETTINGS_MODULE
+passenv = DJANGO_SETTINGS_MODULE PYTHONPATH HOME DISPLAY
+setenv =
+    PYTHONDONTWRITEBYTECODE=1
 deps =
     py{2,27}: -rtests/requirements/py2.txt
     py{3,34,35}: -rtests/requirements/py3.txt