diff --git a/.github/workflows/test.yml b/.github/workflows/test.yml
index 9a34352..0e9b85c 100644
--- a/.github/workflows/test.yml
+++ b/.github/workflows/test.yml
@@ -31,7 +31,7 @@ jobs:
           git config --global init.defaultBranch master
           git config --global user.name  scm_breeze@scm_breeze
           git config --global user.email "SCM Breeze"
-      - run: nix-shell -p bash zsh --run ./run_tests.sh
+      - run: nix-shell -p ruby bash zsh --run ./run_tests.sh
       # - run: nix-shell -p shunit2 -i ./run_tests.sh
       # - run: nix build
       # - run: nix flake check