code: def test_ops(dir_server, block_size):
      root = "http://localhost:8999/"
      fn = files[0]
      f = open_files(root + fn)[0]
      with open(os.path.join(dir_server, fn), "rb") as expected:
          expected = expected.read()
          with f as f:
              # these pass because the default
              assert f.read(10) == expected[:10]
              f.seek(0)
              assert f.read(10) == expected[:10]
              assert f.read(10) == expected[10:20]
              f.seek(-10, 2)
              assert f.read() == 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 5 for calling a global function with example usage: test_ops(dir_server, block_size) without return types