diff --git a/flake.nix b/flake.nix
index 3272d7f..0d630c6 100644
--- a/flake.nix
+++ b/flake.nix
@@ -69,6 +69,7 @@
           nativeBuildInputs = with pkgs; [
             haskellPackages.haskell-language-server
             haskellPackages.fourmolu
+            haskellPackages.hspec-discover
             cabal-install
             ghcid
             nixfmt