(** The bounded FIFO cache: hits, misses, eviction order, and no-op re-adds. *)

let test_find_and_add () =
  let cache = Ogit.Cache.create ~capacity:4 in
  Alcotest.(check (option int)) "miss" None (Ogit.Cache.find cache "a");
  Ogit.Cache.add cache "a" 1;
  Alcotest.(check (option int)) "hit" (Some 1) (Ogit.Cache.find cache "a")

let test_eviction () =
  let cache = Ogit.Cache.create ~capacity:2 in
  Ogit.Cache.add cache "a" 1;
  Ogit.Cache.add cache "b" 2;
  Ogit.Cache.add cache "c" 3;
  Alcotest.(check (option int)) "oldest evicted" None (Ogit.Cache.find cache "a");
  Alcotest.(check (option int)) "second kept" (Some 2) (Ogit.Cache.find cache "b");
  Alcotest.(check (option int)) "newest kept" (Some 3) (Ogit.Cache.find cache "c")

let test_readd_is_noop () =
  let cache = Ogit.Cache.create ~capacity:2 in
  Ogit.Cache.add cache "a" 1;
  Ogit.Cache.add cache "a" 9;
  Alcotest.(check (option int))
    "value unchanged" (Some 1) (Ogit.Cache.find cache "a")

let suite =
  ( "cache",
    [
      Alcotest.test_case "find and add" `Quick test_find_and_add;
      Alcotest.test_case "eviction" `Quick test_eviction;
      Alcotest.test_case "re-add is a no-op" `Quick test_readd_is_noop;
    ] )