diff --git a/tox.ini b/tox.ini
index e0cdeda..8c08984 100644
--- a/tox.ini
+++ b/tox.ini
@@ -24,7 +24,9 @@ commands = {posargs}
 commands = python setup.py test --coverage --testr-args='{posargs}'
 
 [testenv:docs]
-commands = python setup.py build_sphinx
+commands =
+   rm -rf doc/source/ref
+   python setup.py build_sphinx
 
 [testenv:debug]
 commands = oslo_debug_helper {posargs}