let () =
  let id s = s |> B32.encode |> B32.decode |> Result.get_ok in
  let f s =
    let s' = id s in
    match s' = s with
    | false ->
        Fmt.failwith "b32 round trip failure: @\nin :`%S`@\nout:`%S`" s' s
    | true -> ()
  in
  let s = String.init 0xff Char.chr in
  let s_l = List.init 0x0f (fun i -> String.init i Char.chr) in
  f s;
  List.iter f s_l;

  ()