### Question:
NotificationsContainer extends VBox { void addStickyNotification(String title, Node message) { Platform.runLater(() -> { Notification toAdd = doAddNotification(title, message); fadeIn(toAdd, null); }); } NotificationsContainer();   }### Answer:
@Test public void addStickyNotification() { NotificationsContainer victim = new NotificationsContainer(); Label node = new Label("Chuck"); node.setId("chuck"); victim.addStickyNotification("myTitle", node); WaitForAsyncUtils.waitForAsyncFx(2000, () -> assertNotNull(victim.lookup("#chuck"))); }