docstr: Tests generator calculation with a string domain having no vocab.
docstr_tok: ["Tests","generator","calculation","with","a","string","domain","having","no","vocab","."]
code: def test_nl_generator_string_feature_no_vocab(self):
      """Tests generator calculation with a string domain having no vocab."""
      input_batches = [pa.array([[b"Foo"], None, [b"Baz"]])]
      generator = nlsg.NLStatsGenerator(self._schema, None, 0, 0, 0)
      expected_reported_sequences = [["Baz"], ["Foo"]] * 2
      self.assertCombinerOutputEqual(
          input_batches,
          generator,
          self._create_expected_feature_name_statistics(
              feature_coverage=0.5,
              avg_token_length=3,
              min_sequence_length=1,
              max_sequence_length=1,
              reported_sequences=expected_reported_sequences,
          ),
          self._string_nlp_feature_no_vocab_path,
      )
  
imports: from __future__ import absolute_import
  from __future__ import division
  from __future__ import print_function
  import tempfile
  from absl.testing import absltest
  import pyarrow
  from tensorflow_data_validation import types
  from tensorflow_data_validation.statistics.generators import natural_language_stats_generator
  from tensorflow_data_validation.utils import test_util
  from google.protobuf import text_format
  from tensorflow_metadata.proto.v0 import schema_pb2
  from tensorflow_metadata.proto.v0 import statistics_pb2
label_desc: Use image node_id 8 for calling the NaturalLanguageStatsGeneratorTest obj's underlying member method code with example usage: obj.test_nl_generator_string_feature_no_vocab() without return types