{
  perSystem = { pkgs, lib, ... }: {
    # a script that executes all other checks
    packages.impure-checks = pkgs.writeShellScriptBin "impure-checks" ''
      #!${pkgs.bash}/bin/bash
      set -euo pipefail

      export PATH="${lib.makeBinPath [
        pkgs.gitMinimal
        pkgs.nix
        pkgs.rsync # needed to have rsync installed on the dummy ssh server
      ]}"
      ROOT=$(git rev-parse --show-toplevel)
      cd "$ROOT/pkgs/clan-cli"
      nix develop "$ROOT#clan-cli" -c bash -c "TMPDIR=/tmp python -m pytest -s -m impure ./tests $@"
    '';
  };
}
