diff --git a/.github/workflows/test.yml b/.github/workflows/test.yml
index 2f7d682..3356ebe 100644
--- a/.github/workflows/test.yml
+++ b/.github/workflows/test.yml
@@ -27,4 +27,4 @@ jobs:
       - name: install tox
         run: pip3 install tox
       - name: tox
-        run: tox -c 'check out'
+        run: tox -c 'check out' -- -W error