Add non-regression test for previous commit.

testsuite/tests/lib-hashtbl/htbl.ml

@@ -250,3 +250,14 @@ let _ =
   TWSL.test (list_data d);
   printf "-- Weak Kn -- Arrays of strings\n%!";
   TWSA.test (Array.map (fun (l,i) -> (Array.of_list l,i)) (list_data d))
+
+
+let () =
+  let h = Hashtbl.create 16 in
+  for i = 1 to 1000 do Hashtbl.add h i (i * 2) done;
+  Printf.printf "%i elements\n" (Hashtbl.length h);
+  Hashtbl.filter_map_inplace (fun k v -> if k mod 100 = 0 then ((*Hashtbl.add h v v;*) Some (v / 100)) else None) h;
+  let l = Hashtbl.fold (fun k v acc -> (k, v) :: acc) h [] in
+  let l = List.sort compare l in
+  List.iter (fun (k, v) -> Printf.printf "%i,%i\n" k v) l;
+  Printf.printf "%i elements\n" (Hashtbl.length h)

testsuite/tests/lib-hashtbl/htbl.reference

@@ -42,3 +42,15 @@ Removal: passed
 Insertion: passed
 Insertion: passed
 Removal: passed
+1000 elements
+100,2
+200,4
+300,6
+400,8
+500,10
+600,12
+700,14
+800,16
+900,18
+1000,20
+10 elements