ok1(idtree_remove(idtree, INT_MAX-1) == true);
ok1(idtree_add_above(idtree, &i, INT_MAX-1, INT_MAX) == INT_MAX-1);
ok1(idtree_add_above(idtree, &i, INT_MAX-1, INT_MAX) == -1);
ok1(idtree_remove(idtree, INT_MAX-1) == true);
ok1(idtree_add_above(idtree, &i, INT_MAX-1, INT_MAX) == INT_MAX-1);
ok1(idtree_add_above(idtree, &i, INT_MAX-1, INT_MAX) == -1);