@Test
public void testUpdateAge() throws
        Exception {

    final MultiMapChangeHandler changeHandler = mock(MultiMapChangeHandler.class);
    ((ChangeHandledMultiMap) map.get(AGE)).addChangeListener(changeHandler);
    toni.setAge(10);
    final MultiMap<Value, Person, List<Person>> age = map.get(AGE);
    assertFalse(age.get(new Value(20))
                        .contains(toni));
    assertTrue(age.get(new Value(10))
                       .contains(toni));
}