public void testCloning() {
        XYIntervalSeries s1 = new XYIntervalSeries("s1");
        s1.add(1.0, 0.5, 1.5, 2.0, 1.9, 2.01);
        XYIntervalSeries s2 = null;
        try {
            s2 = (XYIntervalSeries) s1.clone();
        }
        catch (CloneNotSupportedException e) {
            e.printStackTrace();
        }
        assertTrue(s1 != s2);
        assertTrue(s1.getClass() == s2.getClass());
        assertTrue(s1.equals(s2));