harness.check(event.getType(), ListDataEvent.INTERVAL_ADDED);
harness.check(event.getIndex0(), 0);
harness.check(event.getIndex1(), 0);
listener.setListDataEvent(null);
m1.insertElementAt("B", 1);
harness.check(m1.getElementAt(1).equals("B"));
event = listener.getEvent();
harness.check(event.getType(), ListDataEvent.INTERVAL_ADDED);
harness.check(event.getIndex0(), 1);
harness.check(event.getIndex1(), 1);