public void testRemove() {
        XIntervalSeries s1 = new XIntervalSeries("Series 1");
        s1.add(1.0, 1.0, 1.0, 2.0);
        s1.add(2.0, 2.0, 2.0, 2.0);
        s1.add(3.0, 3.0, 3.0, 3.0);
        assertEquals(3, s1.getItemCount());

        s1.remove(new Double(2.0));
        assertEquals(new Double(3.0), s1.getX(1));

        s1.remove(new Double(1.0));
        assertEquals(new Double(3.0), s1.getX(0));