(* TEST
files = "foo.ml gen_cached_cmi.ml input.ml"
* setup-ocamlc.byte-build-env
** ocamlc.byte
module = "foo.ml"
*** ocaml with ocamlcommon
ocaml_script_as_argument = "true"
test_file = "gen_cached_cmi.ml"
arguments = "cached_cmi.ml"
**** ocamlc.byte
module = ""
program = "${test_build_directory}/main.exe"
libraries += "ocamlbytecomp ocamltoplevel"
all_modules = "foo.cmo cached_cmi.ml main.ml"
***** run
set OCAMLLIB="${ocamlsrcdir}/stdlib"
arguments = "input.ml"
****** check-program-output
*)

let () =
  (* Make sure it's no longer available on disk *)
  if Sys.file_exists "foo.cmi" then Sys.remove "foo.cmi";
  let module Persistent_signature = Persistent_env.Persistent_signature in
  let old_loader = !Persistent_signature.load in
  Persistent_signature.load := (fun ~unit_name ->
    match unit_name with
    | "Foo" ->
      Some { Persistent_signature.
             filename = Sys.executable_name
           ; cmi      = Marshal.from_string Cached_cmi.foo 0
           }
    | _ -> old_loader unit_name);
  Toploop.add_hook (function
      | Toploop.After_setup ->
          Toploop.toplevel_env :=
            Env.add_persistent_structure (Ident.create_persistent "Foo")
              !Toploop.toplevel_env
      | _ -> ());
  exit (Topmain.main ())