docstr: Make sure the test dir exists and is empty.
docstr_tok: ["Make","sure","the","test","dir","exists","and","is","empty","."]
code: def setUpClass(cls):
      """Make sure the test dir exists and is empty."""
      cls.test_temp_dir = os.path.join(
          tf.test.get_temp_dir(), "encoder_test"
      )
      shutil.rmtree(cls.test_temp_dir, ignore_errors=True)
      tf.gfile.MakeDirs(cls.test_temp_dir)
  
imports: from __future__ import absolute_import
  from __future__ import division
  from __future__ import print_function
  from __future__ import unicode_literals
  import collections
  import io
  import os
  import random
  import shutil
  import string
  import mock
  import six
  from six.moves import range
  from tensor2tensor.data_generators import text_encoder
  import tensorflow.compat.v1
label_desc: Use image node_id 1 for calling the SubwordTextEncoderTest obj's underlying member method code with example usage: obj.setUpClass(cls) without return types