nix-community.nixvim/tests/test-derivation.nix

{
  pkgs,
  makeNixvim,
  makeNixvimWithModule,
}:
let
  # Create a nix derivation from a nixvim executable.
  # The build phase simply consists in running the provided nvim binary.
  mkTestDerivationFromNvim =
    {
      name,
      nvim,
      dontRun ? false,
      ...
    }:
    pkgs.stdenv.mkDerivation {
      inherit name;

      nativeBuildInputs = [
        nvim
        pkgs.docker-client
      ];

      dontUnpack = true;
      # We need to set HOME because neovim will try to create some files
      #
      # Because neovim does not return an exitcode when quitting we need to check if there are
      # errors on stderr
      buildPhase =
        if !dontRun then
          ''
            mkdir -p .cache/nvim

            output=$(HOME=$(realpath .) nvim -mn --headless "+q" 2>&1 >/dev/null)
            if [[ -n $output ]]; then
            	echo "ERROR: $output"
              exit 1
            fi
          ''
        else
          '''';

      # If we don't do this nix is not happy
      installPhase = ''
        mkdir $out
      '';
    };

  mkTestDerivationFromNixvimModule =
    {
      name ? "nixvim-check",
      pkgs,
      module,
      extraSpecialArgs ? { },
    }:
    let
      nvim = makeNixvimWithModule {
        inherit pkgs module extraSpecialArgs;
        _nixvimTests = true;
      };
    in
    mkTestDerivationFromNvim { inherit name nvim; };

  # Create a nix derivation from a nixvim configuration.
  # The build phase simply consists in running neovim with the given configuration.
  mkTestDerivation =
    name: config:
    let
      testAttributes = if builtins.hasAttr "tests" config then config.tests else { dontRun = false; };
      nvim = makeNixvim (pkgs.lib.attrsets.filterAttrs (n: _: n != "tests") config);
    in
    mkTestDerivationFromNvim {
      inherit name nvim;
      inherit (testAttributes) dontRun;
    };
in
{
  inherit mkTestDerivation mkTestDerivationFromNvim mkTestDerivationFromNixvimModule;
}