Support for nix checks

[bew]

Hello!

I'd like to use neorocks to run tests locally, but without having to play with luarocks.

The goal is to use a flake check derivation and run the tests using nix flake check which will try to build theflake.checks.${system}.default and if that builds successfully it means the test is green.

It would eb nice to show in the README or have example projects that shows how to test a neovim plugin like this

[mrcjkb]

Hi. Thanks for your request. I haven't implemented support for tests in a nix derivation yet.

I have something in mind, like a pkgs.neorocksTest function (which will be a wrapper around pkgs.stdenv.mkDerivation) 😄.

There are some issues I need to work out though:

• With the current design (which I originally intended for use with GitHub Actions) luarocks will try to fetch dependencies defined in the rockspec from luarocks.org. This doesn't work in a mkDerivation's checkPhase, because it's impure. It might work with sandboxing disabled, but I would prefer a sandboxed approach.

• Also, on NixOS, and in a derivation's checkPhase, luarocks won't be able to install packages that depend on dynamic libraries (e.g. busted depends on librt), because it can't find them in the nix store.

So the API for a nix flake check might have to look something like this:

checks.${system}.default = neorocksTest {
  src = self;
  luaPackages = p: with p; [ ... ]; # The plugins listed in the rockspec dependencies
  vimPlugins = p: with p; [ ... ]; # Additional vim plugins not available on luarocks
}

[bew]

That interface looks good, maybe also with a name for the derivation name, this can be useful if making multiple kinds of tests or testing multiple plugins.

Could we also choose which neovim derivation to use?

[mrcjkb]

That's a good idea.
By being able to pass in neovim, there's no need for the vimPlugins argument (since you can just pass in a neovim derivation with all the non-luarocks plugins installed).