code: def testCopyDir(self):
      self.createFiles(
          {
              "old": {
                  "file1.txt": "testing",
                  "dir1": {"dir2": {"file2.txt": "testing2"}},
              }
          }
      )
      io_utils.copy_dir(self.relpath("old"), self.relpath("new"))
      self.assertDirectoryEqual(
          self.relpath("new"),
          {
              "file1.txt": "testing",
              "dir1": {"dir2": {"file2.txt": "testing2"}},
          },
      )
  
imports: import os
  from unittest import mock
  import tensorflow
  from tfx.dsl.io import fileio
  from tfx.utils import io_utils
  from tensorflow.python.lib.io import file_io
label_desc: Use image node_id 11 for calling the IoUtilsTest obj's underlying member method code with example usage: obj.testCopyDir() without return types