public void testCloning() {
        TickUnits t1 = (TickUnits) NumberAxis.createIntegerTickUnits();
        TickUnits t2 = null;
        try {
            t2 = (TickUnits) t1.clone();
        }
        catch (CloneNotSupportedException e) {
            e.printStackTrace();
        }
        assertTrue(t1 != t2);
        assertTrue(t1.getClass() == t2.getClass());
        assertTrue(t1.equals(t2));