diff --git a/.github/workflows/black.yml b/.github/workflows/black.yml
index ff761f1..dbfe36a 100644
--- a/.github/workflows/black.yml
+++ b/.github/workflows/black.yml
@@ -19,3 +19,4 @@ jobs:
             --line-length=120
             --target-version=py36
             --check
+            --diff