### Question:
ActivityLogger { public ActivityLogger() { final ObservableList<ActivityItem> list = FXCollections.observableArrayList(); this.activityItems = FXCollections.synchronizedObservableList(list); } ActivityLogger(); void addActivityItem(final ActivityItem item); ObservableList<ActivityItem> getActivityItems(); void clearActivityItems();  }### Answer:
@Test public void testActivityLogger() { assertNotNull(logger); assertNotNull(logger.getActivityItems()); assertTrue(logger.getActivityItems().isEmpty()); }