code: def _test_zero_length(self, model):
      model.eval()
      batch_size = 3
      waveforms = torch.randn(batch_size, 1024)
      input_lengths = torch.zeros(batch_size)
      _, output_lengths = model(waveforms, input_lengths)
      self.assertEqual(torch.zeros_like(output_lengths), output_lengths)
      _, output_lengths = model.extract_features(
          waveforms, input_lengths
      )
      self.assertEqual(torch.zeros_like(output_lengths), output_lengths)
  
imports: import math
  import os
  from typing import Tuple
  import torch
  import torch.nn.functional
  from parameterized import parameterized
  from torchaudio.models.wav2vec2 import hubert_base, hubert_large, hubert_pretrain_base, hubert_pretrain_large, hubert_pretrain_xlarge, hubert_xlarge, wav2vec2_base, wav2vec2_large, wav2vec2_large_lv60k, wavlm_base, wavlm_large
  from torchaudio_unittest.common_utils import skipIfNoCuda, skipIfNoQengine, torch_script, TorchaudioTestCase
label_desc: Use image node_id 9 for calling the TestWav2Vec2Model obj's underlying member method code with example usage: obj._test_zero_length(model) without return types