diff --git a/tox.ini b/tox.ini
index 154be0e..ce0a6ae 100644
--- a/tox.ini
+++ b/tox.ini
@@ -13,8 +13,9 @@ commands = pytest {posargs}
 skip_install = True
 deps =
     flake8
+    flake8-black
 commands =
-    flake8
+    flake8 --select BLK
 
 [testenv:black]
 skip_install = True