code: def test_list_dataset_variants_with_configs_no_versions(
      mock_fs: testing.MockFs,
  ):
      data_dir = epath.Path("/a")
      dataset_dir = data_dir / "my_ds"
      configs_and_versions = {
          "x": ["1.0.0", "1.0.1"],
          "y": ["2.0.0"],
      }
      for config, versions in configs_and_versions.items():
          for version in versions:
              mock_fs.add_file(
                  dataset_dir / config / version / "dataset_info.json"
              )
              mock_fs.add_file(
                  dataset_dir / config / version / "features.json"
              )
  
      references = sorted(
          file_utils.list_dataset_variants(
              dataset_dir=dataset_dir, include_versions=False
          )
      )
      assert references == [
          naming.DatasetReference(
              dataset_name="my_ds", config="x", data_dir=data_dir
          ),
          naming.DatasetReference(
              dataset_name="my_ds", config="y", data_dir=data_dir
          ),
      ]
  
file_path: datasets/tensorflow_datasets/core/utils/file_utils_test.py
imports: import os
  import time
  from unittest import mock
  from absl.testing import flagsaver
  from etils import epath
  import pytest
  from tensorflow_datasets import testing
  from tensorflow_datasets.core import naming
  from tensorflow_datasets.core.utils import file_utils
  from tensorflow_datasets.core.utils import read_config
label_desc: Use image node_id 3 for calling a global function with example usage: test_list_dataset_variants_with_configs_no_versions(mock_fs) without return types