code: def testReadWriteBytes(self):
      file_path = os.path.join(self._base_dir, "test_file")
      content = b"testing read/write"
      io_utils.write_bytes_file(file_path, content)
      read_content = io_utils.read_bytes_file(file_path)
      self.assertEqual(content, read_content)
  
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 21 for calling the IoUtilsTest obj's underlying member method code with example usage: obj.testReadWriteBytes() without return types