code: def test_ops_blocksize(dir_server):
      root = "http://localhost:8999/"
      fn = files[0]
      f = open_files(root + fn, block_size=2)[0]
      with open(os.path.join(dir_server, fn), "rb") as expected:
          expected = expected.read()
          with f as f:
              # it's OK to read the whole file
              assert f.read() == expected
              # and now the file magically has a size
              assert f.size == len(expected)
  
          # note that if we reuse f from above, because it is tokenized, we get
          # the same open file - where is this cached?
          fn = files[1]
          f = open_files(root + fn, block_size=2)[0]
          with f as f:
              if parse_version(fsspec.__version__) < parse_version(
                  "2021.11.1"
              ):
                  # fails because we want only 12 bytes
                  with pytest.raises(ValueError):
                      assert f.read(10) == expected[:10]
              else:
                  # fixed in https://github.com/fsspec/filesystem_spec/pull/830
                  assert f.read(10) == expected[:10]
  
imports: from __future__ import annotations
  import os
  import subprocess
  import sys
  import time
  import fsspec
  import pytest
  from fsspec.core import open_files
  from packaging.version import parse
  import dask.bag
  from dask.utils import tmpdir
label_desc: Use image node_id 6 for calling a global function with example usage: test_ops_blocksize(dir_server) without return types