code: def test_failures(self):
      # Pass non-existing Unicode filenames all over the place.
      for name in self.files:
          name = "not_" + name
          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 4 for calling the UnicodeFileTests obj's underlying member method code with example usage: obj.test_failures() without return types