code: def test_get_requirements_file():
      """Unit test for _PathHelper.get_requirements_file."""
      with tempfile.TemporaryDirectory() as tmpdir:
          path_helper = _PathHelper()
  
          # If pip_list is None, we should return the internal pip filename.
          assert path_helper.get_requirements_file(
              tmpdir, pip_list=None
          ) == os.path.join(tmpdir, INTERNAL_PIP_FILENAME)
  
          # If the internal pip filename is not in pip_list, we should return the internal
          # pip filename.
          assert path_helper.get_requirements_file(
              tmpdir, pip_list=["foo", "bar"]
          ) == os.path.join(tmpdir, INTERNAL_PIP_FILENAME)
  
          # If the internal pip filename is in pip_list, we should append numbers to the
          # end of the filename until we find one that doesn't conflict.
          assert path_helper.get_requirements_file(
              tmpdir,
              pip_list=["foo", "bar", f"-r {INTERNAL_PIP_FILENAME}"],
          ) == os.path.join(tmpdir, f"{INTERNAL_PIP_FILENAME}.1")
          assert path_helper.get_requirements_file(
              tmpdir,
              pip_list=[
                  "foo",
                  "bar",
                  f"{INTERNAL_PIP_FILENAME}.1",
                  f"{INTERNAL_PIP_FILENAME}.2",
              ],
          ) == os.path.join(tmpdir, f"{INTERNAL_PIP_FILENAME}.3")
  
          # If we can't find a valid filename, we should raise an error.
          with pytest.raises(RuntimeError) as excinfo:
              path_helper.get_requirements_file(
                  tmpdir,
                  pip_list=[
                      "foo",
                      "bar",
                      *[
                          f"{INTERNAL_PIP_FILENAME}.{i}"
                          for i in range(
                              MAX_INTERNAL_PIP_FILENAME_TRIES
                          )
                      ],
                  ],
              )
          assert (
              "Could not find a valid filename for the internal "
              in str(excinfo.value)
          )
  
imports: import os
  import pytest
  import sys
  import platform
  import time
  from ray._private.test_utils import wait_for_condition, chdir, check_local_files_gced, generate_runtime_env_dict
  from ray._private.runtime_env.conda import _get_conda_dict_with_ray_inserted
  from ray._private.runtime_env.pip import INTERNAL_PIP_FILENAME, MAX_INTERNAL_PIP_FILENAME_TRIES, _PathHelper
  from ray.runtime_env import RuntimeEnv
  import yaml
  import tempfile
  from pathlib import Path
  import subprocess
  import ray
label_desc: Use image node_id 5 for calling a global function with example usage: test_get_requirements_file() without return types