code: def test_forward_str(self, src_backend_config, dst_backend_config):
      assert dst_backend_config.xp is chainerx
      src_device = src_backend_config.device
      dst_device = dst_backend_config.device
      dst_device_spec = dst_device.device.name
  
      self.check_forward(dst_device_spec, src_device, dst_device)
  
imports: import unittest
  import numpy
  import pytest
  import chainer
  from chainer import backend
  from chainer.backends import _cpu
  from chainer.backends import cuda
  from chainer import functions
  from chainer import testing
  import chainerx
label_desc: Use image node_id 1 for calling the TestCopyToChainerx obj's underlying member method code with example usage: obj.test_forward_str(src_backend_config, dst_backend_config) without return types