code: def test_ensure_datalad_remote_unkown_remote():
      with assert_raises(ValueError):
          ensure_datalad_remote("doesn't matter", "unknown")
  
file_path: datalad/datalad/customremotes/tests/test_base.py
imports: from os.path import isabs
  import pytest
  from datalad.api import Dataset, clone
  from datalad.consts import DATALAD_SPECIAL_REMOTE
  from datalad.support.annexrepo import AnnexRepo
  from datalad.tests.utils_pytest import assert_false, assert_in, assert_not_in, assert_raises, known_failure_githubci_win, with_tempfile, with_tree
  from datalad.utils import Path
  from ..archives import ArchiveAnnexCustomRemote
  from ..base import ensure_datalad_remote, init_datalad_remote
label_desc: Use image node_id 2 for calling a global function with example usage: test_ensure_datalad_remote_unkown_remote() without return types