code: def setUpClass(cls) -> None:
      cls._tmpdir = tempfile.mkdtemp()
      with open(os.path.join(cls._tmpdir, "test.txt"), "w") as f:
          cls._tmpfile = f.name
          f.write(cls._tmpfile_contents)
          f.flush()
  
file_path: fairseq/tests/test_file_io.py
imports: import os
  import shutil
  import sys
  import tempfile
  import unittest
  from typing import Optional
  from unittest.mock import MagicMock
label_desc: Use image node_id 1 for calling the TestFileIO obj's underlying member method code with example usage: obj.setUpClass(cls) without return types