code: def test_forward(self, src_backend_config, dst_backend_config):
      self.check_forward(
          dst_backend_config.device,
          src_backend_config.device,
          dst_backend_config.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 4 for calling the CopyTestBase obj's underlying member method code with example usage: obj.test_forward(src_backend_config, dst_backend_config) without return types