feat(nix): use test suite as base for devShell

.envrc

@@ -1 +1 @@
-use flake -Lv
+use flake . -Lv

CONTRIBUTING.md

@@ -13,18 +13,12 @@ This project uses
 ## Development
 
 I use [`nix`](https://nixos.org/download.html#download-nix)
-for development and testing.
+(with flakes enabled) for development and testing.
 
 Formatting is done with [`stylua`](https://github.com/JohnnyMorganz/StyLua).
 
 To enter a development shell:
 
-```console
-nix-shell
-```
-
-or (with flakes enabled)
-
 ```console
 nix develop
 ```
@@ -40,33 +34,43 @@ just run `direnv allow` and you will be dropped in this devShell.
 
 ## Tests
 
-To run tests locally
+### Running tests
 
-```console
-nix-build -A ci
-```
+I use [`busted`](https://lunarmodules.github.io/busted/) for testing,
+but with Neovim as the Lua interpreter.
 
-or (with flakes enabled)
+The easiest way to run tests is with Nix (see below).
 
-```console
-nix build .#checks.<your-system>.ci --print-build-logs
-```
+If you do not use Nix, you can also run the test suite using `luarocks test`.
+For more information on how to set up Neovim as a Lua interpreter, see
 
-For formatting:
+- The [neorocks tutorial](https://github.com/nvim-neorocks/neorocks#without-neolua).
+
+Or
+
+- [`nlua`](https://github.com/mfussenegger/nlua).
+
+> [!NOTE]
+>
+> The Nix devShell sets up `luarocks test` to use Neovim as the interpreter.
+
+### Running tests and checks with Nix
+
+If you just want to run all checks that are available,
+run:
 
 ```console
-nix-build -A formatting
+nix flake check --print-build-logs
 ```
 
-or (with flakes enabled)
+To run tests locally
 
 ```console
-nix build .#checks.<your-system>.formatting --print-build-logs
+nix build .#checks.<your-system>.ci --print-build-logs
 ```
 
-If you have flakes enabled and just want to run all checks that are available,
-run:
+For formatting:
 
 ```console
-nix flake check --print-build-logs
+nix build .#checks.<your-system>.formatting --print-build-logs
 ```

flake.nix

@@ -104,13 +104,20 @@
           };
         };
 
-        devShell = pkgs.mkShell {
+        devShell = pkgs.nvim-nightly-tests.overrideAttrs (oa: {
           name = "devShell"; # TODO: Choose a name
           inherit (pre-commit-check) shellHook;
-          buildInputs = with pkgs; [
-            zlib
-          ];
-        };
+          buildInputs = with pre-commit-hooks.packages.${system};
+            [
+              alejandra
+              lua-language-server
+              stylua
+              luacheck
+              editorconfig-checker
+              markdownlint-cli
+            ]
+            ++ oa.buildInputs;
+        });
       in {
         devShells = {
           default = devShell;