* @param harness the test harness (<code>null</code> not permitted).
*/
public void test(TestHarness harness)
{
DefaultComboBoxModel m = new DefaultComboBoxModel();
m.addListDataListener(this);
m.insertElementAt("A", 0);
harness.check(m.getSize(), 1);
harness.check(m.getElementAt(0), "A");
harness.check(m.getSelectedItem(), null);