message: Unittest Added to reproduce the bug
diff: @@ -148,6 +148,8 @@ class PrefetchToDeviceTest(test_base.DatasetTestBase, parameterized.TestCase):
  device_dataset = host_dataset.apply(
  prefetching_ops.prefetch_to_device("/gpu:0"))
  + self.assertEqual(device_dataset._variant_tensor.device, '/device:GPU:0')
  +
  iterator = dataset_ops.make_initializable_iterator(device_dataset)
  next_element = iterator.get_next()
  @@ -196,6 +198,8 @@ class PrefetchToDeviceTest(test_base.DatasetTestBase, parameterized.TestCase):
  device_dataset = host_dataset.apply(
  prefetching_ops.prefetch_to_device("/gpu:0"))
  + self.assertEqual(device_dataset._variant_tensor.device, '/device:GPU:0')
  +
  iterator = dataset_ops.make_initializable_iterator(device_dataset)
  next_element = iterator.get_next()
  