let
  lib = import ./../default.nix;
in
{
  "extend" = {
    "lib is extensible" =
      let
        result = lib.extend (
          final: prev:
          prev
          // {
            __injected__ = true;

            fp = prev.fp // {
              __injected__ = true;
            };
          }
        );
      in
      result ? __injected__ && result.fp ? __injected__ && result.fp ? const;
  };
}