code: def testSimpleGpu(self):
      if not test_util.is_gpu_available():
          self.skipTest("No GPU available")
  
      np.random.seed(7)
      with test_util.force_gpu():
          for shape in (2,), (3,), (2, 3), (3, 2), (4, 3, 2):
              rank = len(shape)
              for axis in range(-rank, rank):
                  for dtype in [
                      np.bool_,
                      np.float16,
                      np.float32,
                      np.float64,
                      np.uint8,
                      np.int32,
                      np.int64,
                  ]:
                      data = self.randn(shape, dtype)
                      # Convert data to a single tensorflow tensor
                      x = constant_op.constant(data)
                      # Unstack into a list of tensors
                      ref = self.unstackReference(data, axis)
                      cs = array_ops_stack.unstack(x, axis=axis)
                      self.assertEqual(type(cs), list)
                      self.assertEqual(len(cs), shape[axis])
                      for k, c in enumerate(cs):
                          # Give error with loop context
                          with self.subTest(
                              shape=shape, k=k, axis=axis, dtype=dtype
                          ):
                              self.assertAllEqual(
                                  ref[k], self.evaluate(c)
                              )
  
imports: import numpy
  from tensorflow.python.framework import constant_op
  from tensorflow.python.framework import dtypes
  from tensorflow.python.framework import ops
  from tensorflow.python.framework import test_util
  from tensorflow.python.ops import array_ops
  from tensorflow.python.ops import array_ops_stack
  from tensorflow.python.ops import gradient_checker_v2
  from tensorflow.python.platform import test
label_desc: Use image node_id 4 for calling the UnstackOpTest obj's underlying member method code with example usage: obj.testSimpleGpu() without return types