code: def test_list_directory() -> None:
      root = os.path.join(os.path.dirname(__file__), "fixtures")
  
      assert set(storage.StorageManager._list_directory(root)) == {
          "root.txt",
          "nested/",
          "nested/nested.txt",
          "nested/another.txt",
      }
  
imports: import os
  from typing import Optional
  from unittest import mock
  import pytest
  from determined import core
  from determined.common import storage
label_desc: Use image node_id 5 for calling a global function with example usage: test_list_directory() without return types