code: def testConstruction(self):
      spec1 = sparse_tensor.SparseTensorSpec()
      self.assertEqual(spec1.shape.rank, None)
      self.assertEqual(spec1.dtype, dtypes.float32)
  
      spec2 = sparse_tensor.SparseTensorSpec(
          [None, None], dtypes.string
      )
      self.assertEqual(spec2.shape.as_list(), [None, None])
      self.assertEqual(spec2.dtype, dtypes.string)
  
imports: from absl.testing import parameterized
  import numpy
  from tensorflow.core.framework import full_type_pb2
  from tensorflow.python.eager import context
  from tensorflow.python.eager import def_function
  from tensorflow.python.framework import dtypes
  from tensorflow.python.framework import errors
  from tensorflow.python.framework import ops
  from tensorflow.python.framework import sparse_tensor
  from tensorflow.python.framework import tensor
  from tensorflow.python.framework import tensor_shape
  from tensorflow.python.framework import test_util
  from tensorflow.python.framework.type_utils import fulltypes_for_flat_tensors
  from tensorflow.python.ops import array_ops
  from tensorflow.python.ops import math_ops
  from tensorflow.python.ops import sparse_ops
  from tensorflow.python.platform import googletest
label_desc: Use image node_id 2 for calling the SparseTensorSpecTest obj's underlying member method code with example usage: obj.testConstruction() without return types