diff --git a/tox.ini b/tox.ini
index 0f274506c..8d6ea7067 100644
--- a/tox.ini
+++ b/tox.ini
@@ -8,5 +8,7 @@ envlist = py26, py27, py32, py33
 
 [testenv]
 commands =
+    {envpython} setup.py clean
+    {envpython} setup.py build_ext --inplace
     {envpython} selftest.py
     {envpython} Tests/run.py --installed