code: def test_encode_decode(self):
      tokenizer = XLNetTokenizer.load(self.tmp_dir.name)
  
      input_text = "This is a test"
      output_text = "This is a test"
  
      tokens = tokenizer.map_text_to_token(input_text)
      ids = tokenizer.map_token_to_id(tokens)
      ids_2 = tokenizer.map_text_to_id(input_text)
      self.assertListEqual(ids, ids_2)
  
      tokens_2 = tokenizer.map_id_to_token(ids)
      text_2 = tokenizer.map_id_to_text(ids)
  
      self.assertEqual(text_2, output_text)
  
      self.assertNotEqual(len(tokens_2), 0)
      self.assertIsInstance(text_2, str)
  
imports: import os
  import pickle
  import tempfile
  import tensorflow
  from texar.tf.data.data_utils import maybe_download
  from texar.tf.data.tokenizers.xlnet_tokenizer import XLNetTokenizer, SPIECE_UNDERLINE
  from texar.tf.utils.test import pretrained_test
label_desc: Use image node_id 8 for calling the XLNetTokenizerTest obj's underlying member method code with example usage: obj.test_encode_decode() without return types