code: def test_as_tensor_handles_characters(self):
      field = TextField(
          [Token(t) for t in ["This", "is", "a", "sentence", "."]],
          token_indexers={
              "characters": TokenCharactersIndexer("characters")
          },
      )
      field.index(self.vocab)
      padding_lengths = field.get_padding_lengths()
      tensor_dict = field.as_tensor(padding_lengths)
      expected_character_array = numpy.array(
          [
              [1, 1, 1, 3, 0, 0, 0, 0],
              [1, 3, 0, 0, 0, 0, 0, 0],
              [1, 0, 0, 0, 0, 0, 0, 0],
              [3, 4, 5, 6, 4, 5, 7, 4],
              [1, 0, 0, 0, 0, 0, 0, 0],
          ]
      )
      numpy.testing.assert_array_almost_equal(
          tensor_dict["characters"].detach().cpu().numpy(),
          expected_character_array,
      )
  
imports: from __future__ import with_statement
  from __future__ import absolute_import
  from __future__ import print_function
  from collections import defaultdict
  import pytest
  import numpy
  from allennlp.data import Token, Vocabulary
  from allennlp.data.fields import TextField
  from allennlp.data.token_indexers import SingleIdTokenIndexer, TokenCharactersIndexer, TokenIndexer
  from allennlp.common.testing import AllenNlpTestCase
  from allennlp.common.checks import ConfigurationError
  from allennlp.common.util import pad_sequence_to_length
label_desc: Use image node_id 8 for calling the TestTextField obj's underlying member method code with example usage: obj.test_as_tensor_handles_characters() without return types