### Question:
DetailViewModel implements ViewModel { public ReadOnlyStringProperty roleDepartmentLabelTextProperty() { return roleDepartment.getReadOnlyProperty(); }  void initialize(); Command getEditCommand(); Command getRemoveCommand(); Command getEmailLinkCommand(); ReadOnlyStringProperty nameLabelTextProperty(); ReadOnlyStringProperty birthdayLabelTextProperty(); ReadOnlyStringProperty roleDepartmentLabelTextProperty(); ReadOnlyStringProperty emailLabelTextProperty(); ReadOnlyStringProperty phoneLabelTextProperty(); ReadOnlyStringProperty mobileLabelTextProperty(); ReadOnlyStringProperty cityPostalcodeLabelTextProperty(); ReadOnlyStringProperty streetLabelTextProperty(); ReadOnlyStringProperty countrySubdivisionLabelTextProperty(); static final String OPEN_EDIT_CONTACT_DIALOG; }### Answer:
@Test public void testRoleDepartmentLabelText() { luke.setRole("Pilot"); luke.setDepartment("Rebel Alliance"); obi.setRole("Jedi"); obi.setDepartment(null); selectedContact.set(null); assertThat(viewModel.roleDepartmentLabelTextProperty()).hasValue(""); selectedContact.set(luke); assertThat(viewModel.roleDepartmentLabelTextProperty()).hasValue("Pilot / Rebel Alliance"); selectedContact.set(obi); assertThat(viewModel.roleDepartmentLabelTextProperty()).hasValue("Jedi"); luke.setRole(null); selectedContact.set(luke); assertThat(viewModel.roleDepartmentLabelTextProperty()).hasValue("Rebel Alliance"); obi.setRole(""); obi.setDepartment(""); selectedContact.set(obi); assertThat(viewModel.roleDepartmentLabelTextProperty()).hasValue(""); }