diff --git a/tox.ini b/tox.ini
index cd2ff443a8..f86a0be99a 100644
--- a/tox.ini
+++ b/tox.ini
@@ -12,7 +12,8 @@ deps = -r{toxinidir}/requirements.txt
        -r{toxinidir}/test-requirements.txt
 commands =
   find . -type f -name "*.py[c|o]" -delete
-  ostestr {posargs}
+  stestr run '{posargs}'
+  stestr slowest
 
 [testenv:releasenotes]
 deps =