update project build tooling

flake.nix

@@ -1,29 +1,36 @@
 {
   inputs = {
-    nixpkgs.url = "github:NixOS/nixpkgs/nixos-unstable";
     flake-utils.url = "github:numtide/flake-utils";
   };
 
   outputs = { self, nixpkgs, flake-utils, ... }:
-    flake-utils.lib.eachDefaultSystem(system:
-    let
-      pkgs = import nixpkgs { inherit system; };
-    in rec {
-      devShell = pkgs.mkShell {
-        buildInputs = with pkgs; [
-          poetry
-          (python3.withPackages (ps:
-            with ps; [
-              black
-              isort
-              pylint
-              bandit
-            ]))
-          bashInteractive
-        ];
-        # shellHook = ''
-        #   PYTHONPATH=$PYTHONPATH:$(pwd)
-        # '';
-      };
-    });
+    flake-utils.lib.eachDefaultSystem (system:
+      let
+        pkgs = import nixpkgs { inherit system; };
+      in
+      rec {
+        packages = {
+          pyrad3 = with pkgs; with pkgs.python3Packages; callPackage ./default.nix { };
+        };
+        devShell = pkgs.mkShell
+          {
+            buildInputs = with pkgs;
+              [
+                (python3.withPackages (ps: with ps; [
+                  bandit
+                  black
+                  flake8
+                  flit
+                  isort
+                  pylint
+                  pytest
+                ]))
+                bashInteractive
+              ];
+
+            shellHook = ''
+              export PYTHONPATH=''${PYTHONPATH:+''${PYTHONPATH}:}''$(pwd)/src/
+            '';
+          };
+      });
 }