### Question:
FolderTreeItem extends TreeItem<BoxObject> implements Observer { @Override public boolean isLeaf() { return isLeaf; } FolderTreeItem(BoxFolder folder, ReadableBoxNavigation navigation); BoxPath getPath(); boolean isLoading(); ReadableBoxNavigation getNavigation(); @Override ObservableList<TreeItem<BoxObject>> getChildren(); @Override boolean isLeaf(); StringProperty getNameProperty(); void setUpToDate(Boolean upToDate); @Override void update(Observable o, Object arg); @Override String toString();  }### Answer:
@Test(timeout = 1000) public void isLeafWithoutFiles() { navigation = new FakeBoxNavigation(); item = new FolderTreeItem(createSomeFolder(), navigation); load(); waitUntil(() -> item.isLeaf()); }