diff --git a/.github/workflows/testing.yml b/.github/workflows/testing.yml
index 9c282e9b..cf101dd7 100644
--- a/.github/workflows/testing.yml
+++ b/.github/workflows/testing.yml
@@ -17,7 +17,7 @@ jobs:
 
     strategy:
       matrix:
-        os: ubuntu-latest
+        os: ["ubuntu-latest"]
         python-version: ["3.8", "3.9", "3.10", "3.11", "3.12"]
         include:
           # only test with Python 3.10 on Windows