code: def test_zero_length(self):
      model = conformer_wav2vec2_base()
      model.eval()
  
      batch_size, num_frames, in_features = 3, 1024, 64
      features = torch.randn(batch_size, num_frames, in_features)
      input_lengths = torch.zeros(batch_size)
      _, output_lengths = model(features, input_lengths)
      self.assertEqual(torch.zeros_like(output_lengths), output_lengths)
  
      _, output_lengths = model.extract_features(
          features, input_lengths
      )
      self.assertEqual(torch.zeros_like(output_lengths), output_lengths)
  
file_path: audio/test/torchaudio_unittest/prototype/conformer_wav2vec2_test.py
imports: import torch
  from parameterized import parameterized
  from torchaudio.prototype.models import conformer_wav2vec2_base, conformer_wav2vec2_pretrain_base, conformer_wav2vec2_pretrain_large
  from torchaudio_unittest.common_utils import disabledInCI, nested_params, skipIfNoCuda, torch_script, TorchaudioTestCase
label_desc: Use image node_id 7 for calling the TestConformerWav2Vec2 obj's underlying member method code with example usage: obj.test_zero_length() without return types