public void testCloning_LegendLabelURLGenerator() {
        CustomPieURLGenerator generator = new CustomPieURLGenerator();
        PiePlot p1 = new PiePlot();
        p1.setLegendLabelURLGenerator(generator);
        PiePlot p2 = null;
        try {
            p2 = (PiePlot) p1.clone();
        }
        catch (CloneNotSupportedException e) {
            e.printStackTrace();
        }
        assertTrue(p1 != p2);
        assertTrue(p1.getClass() == p2.getClass());
        assertTrue(p1.equals(p2));
        
        // check that the URL generator has been cloned
        assertTrue(p1.getLegendLabelURLGenerator() 
                != p2.getLegendLabelURLGenerator());