### Question:
AddressFormViewModel implements ViewModel { static ObservableList<String> createListWithNothingSelectedMarker(ObservableList<String> source) { final ObservableList<String> result = FXCollections.observableArrayList(); result.add(NOTHING_SELECTED_MARKER); result.addAll(source); source.addListener((ListChangeListener<String>) c -> { result.clear(); result.add(NOTHING_SELECTED_MARKER); result.addAll(source); }); return result; }  void initialize(); void initWithAddress(Address address); ObservableList<String> countriesList(); ObservableList<String> subdivisionsList(); StringProperty streetProperty(); StringProperty cityProperty(); StringProperty postalCodeProperty(); StringProperty selectedCountryProperty(); StringProperty selectedSubdivisionProperty(); ReadOnlyStringProperty subdivisionLabel(); ReadOnlyBooleanProperty loadingInProgressProperty(); ReadOnlyBooleanProperty countryInputDisabledProperty(); ReadOnlyBooleanProperty subdivisionInputDisabledProperty();  }### Answer:
@Test public void testCreateListWithNothingSelectedMarker() { ObservableList<String> sourceList = FXCollections.observableArrayList(); ObservableList<String> target = AddressFormViewModel .createListWithNothingSelectedMarker(sourceList); assertThat(target).hasSize(1).contains(NOTHING_SELECTED_MARKER); sourceList.add("test"); assertThat(target).hasSize(2).containsExactly(NOTHING_SELECTED_MARKER, "test"); sourceList.add("temp"); assertThat(target).hasSize(3).containsExactly(NOTHING_SELECTED_MARKER, "test", "temp"); sourceList.remove("test"); assertThat(target).hasSize(2).containsExactly(NOTHING_SELECTED_MARKER, "temp"); sourceList.clear(); assertThat(target).hasSize(1).contains(NOTHING_SELECTED_MARKER); }