code: def inject_backend_tests():
      decorator = backend.inject_backend_tests(
          None,
          # CPU tests
          testing.product(
              {
                  "use_cuda": [False],
                  "use_ideep": ["never", "always"],
              }
          )
          # GPU tests
          + [{"use_cuda": True}]
          # ChainerX tests
          + [
              {"use_chainerx": True, "chainerx_device": "native:0"},
              {"use_chainerx": True, "chainerx_device": "cuda:0"},
              {"use_chainerx": True, "chainerx_device": "cuda:1"},
          ],
      )
      return decorator
  
imports: import unittest
  import numpy
  import six
  import chainer
  from chainer import functions
  from chainer import testing
  from chainer.testing import backend
label_desc: Use image node_id 1 for calling a global function with example usage: inject_backend_tests() and returns: decorator