diff --git a/.github/workflows/test-all.yml b/.github/workflows/test-all.yml
index 1d71b0858..05452f837 100644
--- a/.github/workflows/test-all.yml
+++ b/.github/workflows/test-all.yml
@@ -15,6 +15,7 @@ jobs:
     env:
       PRODUCTION: false
     runs-on: ubuntu-latest
+    container: python:3.9-slim-buster
     services:
       postgres:
         image: postgres