code: def test_normalize(self):
      files = set(self.files)
      others = set()
      for nf in set(["NFC", "NFD", "NFKC", "NFKD"]):
          others |= set(normalize(nf, file) for file in files)
      others -= files
      for name in others:
          self._apply_failure(open, name)
          self._apply_failure(os.stat, name)
          self._apply_failure(os.chdir, name)
          self._apply_failure(os.rmdir, name)
          self._apply_failure(os.remove, name)
          self._apply_failure(os.listdir, name)
  
imports: import os
  import sys
  import unittest
  import warnings
  from unicodedata import normalize
  from test.support import os_helper
  from test import support
label_desc: Use image node_id 6 for calling the UnicodeFileTests obj's underlying member method code with example usage: obj.test_normalize() without return types