docstr: Calling clear_session_refs/remove_orphaned_files in an empty manager
  is a no-op.
docstr_tok: ["Calling","clear_session_refs\/remove_orphaned_files","in","an","empty","manager","is","a","no-op","."]
code: def test_remove_orphaned_files_in_empty_manager(self):
      """Calling clear_session_refs/remove_orphaned_files in an empty manager
      is a no-op.
      """
      storage_delete_spy = MagicMock(
          side_effect=self.storage.delete_file
      )
      self.storage.delete_file = storage_delete_spy
  
      self.assertEqual(len(self.media_file_manager._file_metadata), 0)
      self.assertEqual(
          len(self.media_file_manager._files_by_session_and_coord), 0
      )
  
      self.media_file_manager.clear_session_refs()
      self.media_file_manager.remove_orphaned_files()
  
      self.assertEqual(len(self.media_file_manager._file_metadata), 0)
      self.assertEqual(
          len(self.media_file_manager._files_by_session_and_coord), 0
      )
  
      # MediaFileStorage.delete_file should not have been called, because
      # no files were actually deleted.
      storage_delete_spy.assert_not_called()
  
imports: import random
  import unittest
  from typing import Optional
  from unittest import TestCase, mock
  from unittest.mock import MagicMock, call, mock_open
  from streamlit.runtime.media_file_manager import MediaFileManager
  from streamlit.runtime.media_file_storage import MediaFileKind
  from streamlit.runtime.memory_media_file_storage import MemoryFile, MemoryMediaFileStorage, _calculate_file_id
  from tests.exception_capturing_thread import call_on_threads
label_desc: Use image node_id 10 for calling the MediaFileManagerTest obj's underlying member method code with example usage: obj.test_remove_orphaned_files_in_empty_manager() without return types