docstr: MP3 file without extension can be loaded
  
  Originally, we added `format` argument for this case, but now we use FFmpeg
  for MP3 decoding, which works even without `format` argument.
  https://github.com/pytorch/audio/issues/1040
  
  The file was generated with the following command
      ffmpeg -f lavfi -i "sine=frequency=1000:duration=5" -ar 16000 -f mp3 test_noext
code: def test_mp3(self):
      """MP3 file without extension can be loaded
  
      Originally, we added `format` argument for this case, but now we use FFmpeg
      for MP3 decoding, which works even without `format` argument.
      https://github.com/pytorch/audio/issues/1040
  
      The file was generated with the following command
          ffmpeg -f lavfi -i "sine=frequency=1000:duration=5" -ar 16000 -f mp3 test_noext
      """
      path = get_asset_path("mp3_without_ext")
      sinfo = self._info(path)
      assert sinfo.sample_rate == 16000
      assert sinfo.num_frames == 80000
      assert sinfo.num_channels == 1
      assert (
          sinfo.bits_per_sample == 0
      )  # bit_per_sample is irrelevant for compressed formats
      assert sinfo.encoding == "MP3"
  
      with open(path, "rb") as fileobj:
          sinfo = self._info(fileobj, format="mp3")
      assert sinfo.sample_rate == 16000
      assert sinfo.num_frames == 80000
      assert sinfo.num_channels == 1
      assert sinfo.bits_per_sample == 0
      assert sinfo.encoding == "MP3"
  
imports: import io
  import itertools
  import os
  import pathlib
  import tarfile
  from contextlib import contextmanager
  from functools import partial
  from parameterized import parameterized
  from torchaudio._backend.utils import get_info_func
  from torchaudio._internal import module_utils
  from torchaudio.utils.sox_utils import get_buffer_size, set_buffer_size
  from torchaudio_unittest.backend.common import get_bits_per_sample, get_encoding
  from torchaudio_unittest.backend.dispatcher.sox.common import name_func
  from torchaudio_unittest.common_utils import get_asset_path, get_wav_data, HttpServerMixin, PytorchTestCase, save_wav, skipIfNoExec, skipIfNoFFmpeg, skipIfNoModule, sox_utils, TempDirMixin
label_desc: Use image node_id 1 for calling the TestLoadWithoutExtension obj's underlying member method code with example usage: obj.test_mp3() without return types