code: def test_listdir(self):
      sf0 = set(self.files)
      with warnings.catch_warnings():
          warnings.simplefilter("ignore", DeprecationWarning)
          f1 = os.listdir(
              os_helper.TESTFN.encode(sys.getfilesystemencoding())
          )
      f2 = os.listdir(os_helper.TESTFN)
      sf2 = set(os.path.join(os_helper.TESTFN, f) for f in f2)
      self.assertEqual(sf0, sf2, "%a != %a" % (sf0, sf2))
      self.assertEqual(len(f1), len(f2))
  
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 7 for calling the UnicodeFileTests obj's underlying member method code with example usage: obj.test_listdir() without return types