use makefile instead of script in flake.nix

flake.lock

@@ -1,40 +1,6 @@
 {
   "nodes": {
-    "flake-utils": {
-      "locked": {
-        "lastModified": 1667395993,
-        "narHash": "sha256-nuEHfE/LcWyuSWnS8t12N1wc105Qtau+/OdUAjtQ0rA=",
-        "owner": "numtide",
-        "repo": "flake-utils",
-        "rev": "5aed5285a952e0b949eb3ba02c12fa4fcfef535f",
-        "type": "github"
-      },
-      "original": {
-        "owner": "numtide",
-        "repo": "flake-utils",
-        "type": "github"
-      }
-    },
-    "nixpkgs": {
-      "locked": {
-        "lastModified": 1669045945,
-        "narHash": "sha256-BQxzijvZpLQ7R+KuQzCPcFgIS6OK0Onb29pYFe2pzJo=",
-        "owner": "NixOS",
-        "repo": "nixpkgs",
-        "rev": "6b5019a48f876f3288efc626fa8b70ad0c64eb46",
-        "type": "github"
-      },
-      "original": {
-        "id": "nixpkgs",
-        "type": "indirect"
-      }
-    },
-    "root": {
-      "inputs": {
-        "flake-utils": "flake-utils",
-        "nixpkgs": "nixpkgs"
-      }
-    }
+    "root": {}
   },
   "root": "root",
   "version": 7

flake.nix

@@ -1,24 +1,5 @@
 {
-  inputs = {
-    flake-utils.url = "github:numtide/flake-utils";
-  };
+  inputs = { };
 
-  outputs = { self, nixpkgs, flake-utils }:
-    {
-      lib = import ./lib.nix;
-    }
-    // flake-utils.lib.eachDefaultSystem (system:
-      let
-        pkgs = import nixpkgs { inherit system; };
-
-        runTests = pkgs.writeShellScript "runTests" ''
-          nix eval --impure --expr 'import ./lib.test.nix {}'
-        '';
-      in
-      {
-        apps.tests = {
-          type = "app";
-          program = toString runTests;
-        };
-      });
+  outputs = { ... }: { lib = import ./lib.nix; };
 }

makefile

@@ -0,0 +1,5 @@
+
+# Run all tests
+test:
+	nix eval --impure --expr 'import ./lib.test.nix {}'
+