@Test
    public void testRemoveAdjacent() {
        ObservableList<Integer> original = FXCollections.observableArrayList(
                1, 2, 3, 4 ,5, 6, 7, 8
                );
        SortedList<Integer> sorted = new SortedList<Integer>(original);
        original.removeAll(Arrays.asList(original.get(0), original.get(1)));
        original.removeAll(Arrays.asList(original.get(0), original.get(1)));
    }