open! Core

module Make (M : sig
    val am_running_test : bool
  end) =
struct
  type 'a t = 'a [@@deriving bin_io, compare, sexp]

  let sexp_of_t sexp_of_a a =
    if M.am_running_test then Sexp.Atom "<hidden_in_test>" else sexp_of_a a
  ;;

  module With_non_roundtripping_in_test_of_sexp = struct
    type nonrec 'a t = 'a t [@@deriving bin_io, compare, sexp]
  end
end

let%test_module _ =
  (module struct
    module Turned_off = struct
      module Sexp_hidden_in_test_turned_off = Make (struct
          let am_running_test = false
        end)

      type nonrec t = int Sexp_hidden_in_test_turned_off.t [@@deriving sexp_of]
    end

    module Turned_on = struct
      module Sexp_hidden_in_test_turned_on = Make (struct
          let am_running_test = true
        end)

      type nonrec t = int Sexp_hidden_in_test_turned_on.t [@@deriving sexp_of]
    end

    let%expect_test "Turned on" =
      print_s [%sexp (1024 : Turned_on.t)];
      [%expect {| <hidden_in_test> |}]
    ;;

    let%expect_test "Turned off" =
      print_s ([%sexp_of: Turned_off.t] 1024);
      [%expect {| 1024 |}]
    ;;
  end)
;;

include Make (struct
    let am_running_test = am_running_test
  end)
