module Test = (val Containers_testlib.make ~__FILE__())
open Test

type elt = {
  x: string;
  mutable rank: int;
  mutable idx: int;
}
module Elt = struct
  type t = elt
  let idx x = x.idx
  let set_idx x i = x.idx <- i
  let lt a b =
    if a.rank = b.rank then a.x < b.x else a.rank < b.rank
end
module H = CCMutHeap.Make(Elt);;

t @@ fun () ->
  let h = H.create() in
  let x1 = {x="a"; rank=10; idx= -1} in
  let x2 = {x="b"; rank=10; idx= -1} in
  let x3 = {x="c"; rank=10; idx= -1} in
  H.insert h x1;
  assert (H.in_heap x1);
  assert (not (H.in_heap x2));
  assert (not (H.in_heap x3));
  H.insert h x2;
  H.insert h x3;

  assert (Elt.lt x1 x2);
  assert (Elt.lt x2 x3);

  let x = H.remove_min h in
  assert (x == x1);

  let x = H.remove_min h in
  assert (x == x2);

  let x = H.remove_min h in
  assert (x == x3);

  assert (try ignore (H.remove_min h); false with Not_found -> true);
  true;;

t @@ fun () ->
  let h = H.create() in
  let x1 = {x="a"; rank=10; idx= -1} in
  let x2 = {x="b"; rank=10; idx= -1} in
  let x3 = {x="c"; rank=10; idx= -1} in
  H.insert h x1;
  H.insert h x2;
  H.insert h x3;

  x3.rank <- 2;
  H.decrease h x3;

  assert (Elt.lt x3 x1);
  assert (Elt.lt x3 x2);

  let x = H.remove_min h in
  assert (x == x3);

  x1.rank <- 20;
  H.increase h x1;

  let x = H.remove_min h in
  assert (x == x2);

  let x = H.remove_min h in
  assert (x == x1);

  assert (try ignore (H.remove_min h); false with Not_found -> true);
  true;;