code: def testPrepareDataIndex(self):
      tmp_dir = self.get_temp_dir()
      self._saveWavFolders(tmp_dir, ["a", "b", "c"], 100)
      audio_processor = input_data.AudioProcessor(
          "",
          tmp_dir,
          10,
          10,
          ["a", "b"],
          10,
          10,
          self._model_settings(),
          tmp_dir,
      )
      self.assertLess(0, audio_processor.set_size("training"))
      self.assertIn("training", audio_processor.data_index)
      self.assertIn("validation", audio_processor.data_index)
      self.assertIn("testing", audio_processor.data_index)
      self.assertEqual(
          input_data.UNKNOWN_WORD_INDEX,
          audio_processor.word_to_index["c"],
      )
  
imports: import os
  import numpy
  import tensorflow
  from tensorflow.examples.speech_commands import input_data
  from tensorflow.examples.speech_commands import models
  from tensorflow.python.framework import test_util
  from tensorflow.python.platform import test
label_desc: Use image node_id 8 for calling the InputDataTest obj's underlying member method code with example usage: obj.testPrepareDataIndex() without return types