code: def test_preprocess_decompress(self, tmp_path, preprocess):
      file_name = "file.txt.gz"
      content = "sentinel"
  
      def download_fn(resource, root):
          file = root / resource.file_name
          with gzip.open(file, "wb") as fh:
              fh.write(content.encode())
          return file
  
      resource = self.DummyResource(
          file_name=file_name,
          preprocess=preprocess,
          download_fn=download_fn,
      )
  
      dp = resource.load(tmp_path)
      data = list(dp)
      assert len(data) == 1
  
      path, buffer = data[0]
      assert path == str(tmp_path / file_name).replace(".gz", "")
      assert buffer.read().decode() == content
  
imports: import gzip
  import pathlib
  import sys
  import numpy
  import pytest
  import torch
  from datasets_utils import make_fake_flo_file, make_tar
  from torchdata.datapipes.iter import FileOpener, TarArchiveLoader
  from torchvision.datasets._optical_flow import _read_flo
  from torchvision.datasets.utils import _decompress
  from torchvision.prototype.datasets.utils import Dataset, GDriveResource, HttpResource, OnlineResource
  from torchvision.prototype.datasets.utils._internal import fromfile, read_flo
label_desc: Use image node_id 10 for calling the TestOnlineResource obj's underlying member method code with example usage: obj.test_preprocess_decompress(tmp_path, preprocess) and returns: file