message: removed test_util based parent class
diff: @@ -35,7 +35,6 @@ from tensorflow.python.framework import ops
  from tensorflow.python.framework import sparse_tensor
  from tensorflow.python.framework import tensor_shape
  from tensorflow.python.framework import tensor_spec
  -from tensorflow.python.framework import test_util
  from tensorflow.python.ops import array_ops
  from tensorflow.python.ops import tensor_array_ops
  from tensorflow.python.ops import variables
  @@ -51,8 +50,7 @@ from tensorflow.python.util.compat import collections_abc
  # has been set up.
  #
  # TODO(jsimsa): Add tests for OptionalStructure and DatasetStructure.
  -class StructureTest(test_base.DatasetTestBase, parameterized.TestCase,
  - test_util.TensorFlowTestCase):
  +class StructureTest(test_base.DatasetTestBase, parameterized.TestCase):
  # pylint: disable=g-long-lambda,protected-access
  @parameterized.named_parameters(
  