public void testCloning_QuadrantPaint() {
        XYPlot p1 = new XYPlot();
        p1.setQuadrantPaint(3, new GradientPaint(1.0f, 2.0f, Color.red, 
                3.0f, 4.0f, Color.blue));
        XYPlot p2 = null;
        try {
            p2 = (XYPlot) p1.clone();
        }
        catch (CloneNotSupportedException e) {
            e.printStackTrace();
        }
        assertTrue(p1 != p2);
        assertTrue(p1.getClass() == p2.getClass());
        assertTrue(p1.equals(p2));
        
        // check for independence
        p1.setQuadrantPaint(1, Color.red);
        assertFalse(p1.equals(p2));
        p2.setQuadrantPaint(1, Color.red);
        assertTrue(p1.equals(p2));