add pytest to flake

flake.lock

@@ -2,14 +2,18 @@
   "nodes": {
     "nixpkgs": {
       "locked": {
-        "lastModified": 0,
-        "narHash": "sha256-TvODmeR2W7yX/JmOCmP+lAFNkTT7hAxYcF3Kz8SZV3w=",
-        "path": "/nix/store/mzchpp2c3mgdzl6ah0qxwcxg32cnlcfv-source",
-        "type": "path"
+        "lastModified": 1764522689,
+        "narHash": "sha256-SqUuBFjhl/kpDiVaKLQBoD8TLD+/cTUzzgVFoaHrkqY=",
+        "owner": "nixos",
+        "repo": "nixpkgs",
+        "rev": "8bb5646e0bed5dbd3ab08c7a7cc15b75ab4e1d0f",
+        "type": "github"
       },
       "original": {
-        "id": "nixpkgs",
-        "type": "indirect"
+        "owner": "nixos",
+        "ref": "nixos-25.11",
+        "repo": "nixpkgs",
+        "type": "github"
       }
     },
     "root": {

flake.nix

@@ -1,10 +1,11 @@
 {
+  inputs.nixpkgs.url = "github:nixos/nixpkgs/nixos-25.11";
   outputs =
     { nixpkgs, ... }:
     {
       devShells.x86_64-linux =
         let
-          python = pkgs.python312Full;
+          python = pkgs.python312;
           pythonEnv = python.withPackages (
             ps: with ps; [
               pip
@@ -15,6 +16,7 @@
 
               ruff
               jedi-language-server
+              pytest
             ]
           );
           pkgs = import nixpkgs { system = "x86_64-linux"; };