docstr: `info` can check opus file correcty
code: def test_opus(self, bitrate, num_channels, compression_level):
      """`info` can check opus file correcty"""
      path = get_asset_path(
          "io", f"{bitrate}_{compression_level}_{num_channels}ch.opus"
      )
      info = self._info(path)
      assert info.sample_rate == 48000
      assert info.num_frames == 32768
      assert info.num_channels == num_channels
      assert (
          info.bits_per_sample == 0
      )  # bit_per_sample is irrelevant for compressed formats
      assert info.encoding == "OPUS"
  
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 TestInfoOpus obj's underlying member method code with example usage: obj.test_opus(bitrate, num_channels, compression_level) without return types