public void testCloning() {
        RingPlot p1 = new RingPlot(null);
        GradientPaint gp = new GradientPaint(1.0f, 2.0f, Color.yellow,
                3.0f, 4.0f, Color.red);
        p1.setSeparatorPaint(gp);
        RingPlot p2 = null;
        try {
            p2 = (RingPlot) p1.clone();
        }
        catch (CloneNotSupportedException e) {
            e.printStackTrace();
        }
        assertTrue(p1 != p2);
        assertTrue(p1.getClass() == p2.getClass());
        assertTrue(p1.equals(p2));