public void testCloning() {
        XYLine3DRenderer r1 = new XYLine3DRenderer();
        r1.setWallPaint(new GradientPaint(1.0f, 2.0f, Color.red, 3.0f, 4.0f,
                Color.blue));
        XYLine3DRenderer r2 = null;
        try {
            r2 = (XYLine3DRenderer) r1.clone();
        }
        catch (CloneNotSupportedException e) {
            e.printStackTrace();
        }
        assertTrue(r1 != r2);
        assertTrue(r1.getClass() == r2.getClass());
        assertTrue(r1.equals(r2));