/** Some basic checks for the clone() method. */
 public void testCloning() {
   MultiplePiePlot p1 = new MultiplePiePlot();
   MultiplePiePlot p2 = null;
   try {
     p2 = (MultiplePiePlot) p1.clone();
   } catch (CloneNotSupportedException e) {
     e.printStackTrace();
     System.err.println("Failed to clone.");
   }
   assertTrue(p1 != p2);
   assertTrue(p1.getClass() == p2.getClass());
   assertTrue(p1.equals(p2));
 }