diff --git a/tox.ini b/tox.ini
index 4f144197f..6d19a7bd3 100644
--- a/tox.ini
+++ b/tox.ini
@@ -12,7 +12,9 @@ setenv = VIRTUAL_ENV={envdir}
 
 deps = -r{toxinidir}/requirements.txt
        -r{toxinidir}/test-requirements.txt
-commands = python setup.py testr --slowest --testr-args='{posargs}'
+commands = find . -type f -name "*.pyc" -delete
+           python setup.py testr --slowest --testr-args='{posargs}'
+whitelist_externals = find
 
 [testenv:pep8]
 commands =