diff --git a/shell.nix b/shell.nix
index b7f96c4..16a2420 100644
--- a/shell.nix
+++ b/shell.nix
@@ -15,6 +15,7 @@ pkgs.mkShell {
   buildInputs = with pkgs; [
     zstd
     openssl
+    (python3.withPackages (ps: with ps; [ pytest ]))
   ];
 
   NIX_ENFORCE_PURITY = 0;