code: @Test public void should_mark_dirty_on_element_add() throws Exception {
    List<Object> target=new ArrayList<>();
    ListWrapper wrapper=prepareListWrapper(target);
    when(proxifier.removeProxy("a")).thenReturn("a");
    wrapper.add("a");
    assertThat(target).containsExactly("a");
    DirtyChecker dirtyChecker=dirtyMap.get(setter);
    assertThat(dirtyChecker.getPropertyMeta()).isEqualTo(propertyMeta);
    DirtyCheckChangeSet changeSet=dirtyChecker.getChangeSets().get(0);
    assertThat(changeSet.getChangeType()).isEqualTo(APPEND_TO_LIST);
    assertThat(changeSet.getPropertyMeta()).isEqualTo(propertyMeta);
    assertThat(changeSet.getRawListChanges()).containsExactly("a");
  }
  