diff --git a/.github/workflows/pytest.yml b/.github/workflows/pytest.yml
index 1151780..063a3f5 100644
--- a/.github/workflows/pytest.yml
+++ b/.github/workflows/pytest.yml
@@ -16,4 +16,4 @@ jobs:
     steps:
       - uses: actions/checkout@v4
       - name: Run tests
-        run: pytest tests
+        run: nix develop .#devShells.x86_64-linux.default -c pytest tests
diff --git a/flake.nix b/flake.nix
index bca9eee..efa5cac 100644
--- a/flake.nix
+++ b/flake.nix
@@ -59,6 +59,7 @@
         system:
         import nixpkgs {
           inherit system;
+          overlays = builtins.attrValues outputs.overlays;
           config.allowUnfree = true;
         }
       );
diff --git a/shell.nix b/shell.nix
index 9f42968..b8a7742 100644
--- a/shell.nix
+++ b/shell.nix
@@ -9,6 +9,7 @@
       nix
       home-manager
       git
+      my_python
 
       ssh-to-age
       gnupg