code: def test_conversion(self):
      stop = True
      is_valid_data_type = True
      is_paired_dataset = True
      is_new_epoch = True
      current_position = 0
      msg = _build_ctrl_msg(
          stop,
          is_valid_data_type,
          is_paired_dataset,
          is_new_epoch,
          current_position,
      )
      np.testing.assert_array_equal(
          msg, _build_ctrl_msg(*_parse_ctrl_msg(msg))
      )
  
imports: import chainer
  import chainer.testing
  import chainer.testing.attr
  import chainermn
  from chainermn.iterators.multi_node_iterator import _build_ctrl_msg
  from chainermn.iterators.multi_node_iterator import _parse_ctrl_msg
  import numpy
  import platform
  import pytest
  from six.moves import range
  import unittest
label_desc: Use image node_id 1 for calling the TestCntrlMessageConversion obj's underlying member method code with example usage: obj.test_conversion() without return types