code: def testCopyFile(self):
      self.createFiles({"file1.txt": "testing"})
      io_utils.copy_file(
          self.relpath("file1.txt"), self.relpath("file2.txt")
      )
      self.assertDirectoryEqual(
          self._base_dir,
          {"file1.txt": "testing", "file2.txt": "testing"},
      )
  
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 10 for calling the IoUtilsTest obj's underlying member method code with example usage: obj.testCopyFile() without return types