diff --git a/tox.ini b/tox.ini
index 9799e10..a1c7f9d 100644
--- a/tox.ini
+++ b/tox.ini
@@ -1,5 +1,5 @@
 [tox]
-envlist = py3-junit-coverage
+envlist = py3-black-junit-coverage
 toxworkdir = {env:TMPDIR:/tmp}/tox-{env:USER}/combo-plugin-gnm/{env:BRANCH_NAME:}
 
 [testenv]
@@ -28,5 +28,7 @@ deps =
   django>=2.2,<2.3
   https://git.entrouvert.org/debian/django-ckeditor.git/snapshot/django-ckeditor-main.tar.gz
   https://git.entrouvert.org/combo.git/snapshot/combo-main.tar.gz
+  pre-commit
 commands =
   py.test {posargs: {env:JUNIT:} {env:COVERAGE:} tests/}
+  black: pre-commit run black --all-files --show-diff-on-failure