{ lib, formats, stdenvNoCC, writeText, ... }:
let
  libconfig = formats.libconfig { };

  include_expr = {
    val = 1;
  };

  include_file = writeText "libconfig-test-include" ''
    val=1;
  '';

  expression = {
    simple_top_level_attr = "1.0";
    nested.attrset.has.a.integer.value = 100;
    some_floaty = 29.95;
    ## Same syntax here on these two, but they should get serialized differently:
    # > A list may have zero or more elements, each of which can be a scalar value, an array, a group, or another list.
    list1d = libconfig.lib.mkList [ 1 "mixed!" 5 2 ];
    # You might also omit the mkList, as a list will be a list (in contrast to an array) by default.
    list2d = [ 1 [ 1 1.2 "foo" ] [ "bar" 1.2 1 ] ];
    # > An array may have zero or more elements, but the elements must all be scalar values of the same type.
    array1d = libconfig.lib.mkArray [ 1 5 2 ];
    array2d = [
      (libconfig.lib.mkArray [ 1 2 ])
      (libconfig.lib.mkArray [ 2 1 ])
    ];
    nasty_string = "\"@\n\\\t^*\b\f\n\0\";'''$";

    weirderTypes = {
      _includes = [ include_file ];
      pi = 3.141592654;
      bigint = 9223372036854775807;
      hex = libconfig.lib.mkHex "0x1FC3";
      octal = libconfig.lib.mkOctal "0027";
      float = libconfig.lib.mkFloat "1.2E-3";
      array_of_ints = libconfig.lib.mkArray [
        (libconfig.lib.mkOctal "0732")
        (libconfig.lib.mkHex "0xA3")
        1234
      ];
      list_of_weird_types = [
        3.141592654
        9223372036854775807
        (libconfig.lib.mkHex "0x1FC3")
        (libconfig.lib.mkOctal "0027")
        (libconfig.lib.mkFloat "1.2E-32")
        (libconfig.lib.mkFloat "1")
      ];
    };
  };

  libconfig-test-cfg = libconfig.generate "libconfig-test.cfg" expression;
in
  stdenvNoCC.mkDerivation {
    name = "pkgs.formats.libconfig-test-comprehensive";

    dontUnpack = true;
    dontBuild = true;

    doCheck = true;
    checkPhase = ''
      cp ${./expected.txt} expected.txt
      substituteInPlace expected.txt \
          --subst-var-by include_file "${include_file}"
      diff -U3 ./expected.txt ${libconfig-test-cfg}
    '';

    installPhase = ''
      mkdir $out
      cp expected.txt $out
      cp ${libconfig-test-cfg} $out/libconfig-test.cfg
      cp ${libconfig-test-cfg.passthru.json} $out/libconfig-test.json
    '';
  }

