@Test
@SuppressWarnings("LocalVariableName")
public void testCombineListsListeners() {

  ObservableList<String> a = FXCollections.observableArrayList("a");
  ObservableList<String> b = FXCollections.observableArrayList("b");
  ObservableList<String> combine = PropertyUtils.combineLists(a, b);
  a.add("A");
  assertEquals(3, combine.size());
  b.add("B");
  assertEquals(4, combine.size());
  assertEquals(a.get(1), combine.get(2));
  assertEquals(b.get(1), combine.get(3));
  a.clear();
  b.clear();
  assertEquals(0, combine.size());
}