import tensorflow as tf

                                         validate_args=True)
      self.assertFalse(tensor_util.constant_value(mvn.is_scalar_event))
      self.assertFalse(tensor_util.constant_value(mvn.is_scalar_batch))

      # We now test every codepath within the underlying is_scalar_helper
      # function.

      # Test case 1, 2.
      x = tf.placeholder(dtype=tf.int32, shape=[])
      # None would fire an exception were it actually executed.
      self.assertTrue(normal._is_scalar_helper(x.get_shape, lambda: None))
      self.assertTrue(normal._is_scalar_helper(lambda: tf.TensorShape(None),
                                               lambda: tf.shape(x)))

      x = tf.placeholder(dtype=tf.int32, shape=[1])
      # None would fire an exception were it actually executed.
