class_docstr: Test ByteLevelBPE is well-behaved.
class_docstr_tok: ["Test","ByteLevelBPE","is","well-behaved","."]
docstr: Tests a bytelevel bpe tokenizer inside ParlAI.
code: def test_tokenize_prefix_space(self):
      """
      Tests a bytelevel bpe tokenizer inside ParlAI.
      """
      parser = ParlaiParser()
      parser.set_params(
          dict_tokenizer="bytelevelbpe",
          bpe_vocab=DEFAULT_BYTELEVEL_BPE_VOCAB,
          bpe_merge=DEFAULT_BYTELEVEL_BPE_MERGE,
      )
      opt = parser.parse_args([])
      agent = DictionaryAgent(opt)
      self.assertEqual(
          # grinning face emoji
          agent.bytelevelbpe_tokenize("Hello, ParlAI! \U0001f600"),
          ["Ġ"] + BYTELEVEL_BPE_RESULT,
      )
      self.assertEqual(
          agent.vec2txt(
              [agent.tok2ind[w] for w in ["Ġ"] + BYTELEVEL_BPE_RESULT]
          ),
          # grinning face emoji
          "Hello, ParlAI! \U0001f600",
      )
      self.assertEqual(
          agent.txt2vec("Hello, ParlAI! \U0001f600"),
          [agent.tok2ind[w] for w in ["Ġ"] + BYTELEVEL_BPE_RESULT],
      )
  
imports: from parlai.core.build_data import modelzoo_path
  from parlai.core.dict import find_ngrams
  from parlai.core.params import ParlaiParser
  from parlai.core.dict import DictionaryAgent, TokenizationMode
  from parlai.core.opt import Opt
  import parlai.scripts.build_dict
  from parlai.utils.io import PathManager
  import parlai.utils.testing
  import os
  import shutil
  import unittest
  import pytest
label_desc: Use image node_id 1 for calling the TestByteLevelBPE obj's underlying member method code with example usage: obj.test_tokenize_prefix_space() without return types