code: def test_load_audio(self, test_data_dir):
      sample_rate = 22050
      test_data_dir = Path(test_data_dir)
      audio_filepath_rel = Path("tts/mini_ljspeech/wavs/LJ003-0182.wav")
      audio_filepath = test_data_dir / audio_filepath_rel
      manifest_entry = {"audio_filepath": str(audio_filepath_rel)}
  
      expected_audio, _ = librosa.load(
          path=audio_filepath, sr=sample_rate
      )
      audio, _, _ = load_audio(
          manifest_entry=manifest_entry,
          audio_dir=test_data_dir,
          sample_rate=sample_rate,
      )
  
      np.testing.assert_array_almost_equal(audio, expected_audio)
  
imports: from pathlib import Path
  import librosa
  import numpy
  import pytest
  import torch
  from nemo.collections.tts.parts.utils.tts_dataset_utils import filter_dataset_by_duration, get_abs_rel_paths, get_audio_filepaths, load_audio, normalize_volume, stack_tensors
label_desc: Use image node_id 4 for calling the TestTTSDatasetUtils obj's underlying member method code with example usage: obj.test_load_audio(test_data_dir) without return types