code: def test_ctor_with_datafile():
      from cugraph.datasets import karate
  
      karate_csv = RAPIDS_DATASET_ROOT_DIR_PATH / "karate.csv"
  
      # test that only a metadata file or csv can be specified, not both
      with pytest.raises(ValueError):
          datasets.Dataset(
              metadata_yaml_file="metadata_file", csv_file=karate_csv
          )
  
      # ensure at least one arg is provided
      with pytest.raises(ValueError):
          datasets.Dataset()
  
      # ensure csv file has all other required args (col names and col dtypes)
      with pytest.raises(ValueError):
          datasets.Dataset(csv_file=karate_csv)
  
      with pytest.raises(ValueError):
          datasets.Dataset(
              csv_file=karate_csv, csv_col_names=["src", "dst", "wgt"]
          )
  
      # test with file that DNE
      with pytest.raises(FileNotFoundError):
          datasets.Dataset(
              csv_file="/some/file/that/does/not/exist",
              csv_col_names=["src", "dst", "wgt"],
              csv_col_dtypes=["int32", "int32", "float32"],
          )
  
      expected_karate_edgelist = karate.get_edgelist(download=True)
  
      # test with file path as string, ensure download=True does not break
      ds = datasets.Dataset(
          csv_file=karate_csv.as_posix(),
          csv_col_names=["src", "dst", "wgt"],
          csv_col_dtypes=["int32", "int32", "float32"],
      )
      # cudf.testing.testing.assert_frame_equal() would be good to use to
      # compare, but for some reason it seems to be holding a reference to a
      # dataframe and gc.collect() does not free everything
      el = ds.get_edgelist()
      assert len(el) == len(expected_karate_edgelist)
      assert str(ds) == "karate"
      assert ds.get_path() == karate_csv
  
      # test with file path as Path object
      ds = datasets.Dataset(
          csv_file=karate_csv,
          csv_col_names=["src", "dst", "wgt"],
          csv_col_dtypes=["int32", "int32", "float32"],
      )
      el = ds.get_edgelist()
      assert len(el) == len(expected_karate_edgelist)
      assert str(ds) == "karate"
      assert ds.get_path() == karate_csv
  
imports: import os
  import gc
  from pathlib import Path
  from tempfile import TemporaryDirectory
  import pandas
  import pytest
  import cudf
  import dask_cudf
  from cugraph.structure import Graph
  from cugraph.testing import RAPIDS_DATASET_ROOT_DIR_PATH, ALL_DATASETS, WEIGHTED_DATASETS, SMALL_DATASETS, BENCHMARKING_DATASETS
  from cugraph import datasets
  from cugraph.dask.common.mg_utils import is_single_gpu
label_desc: Use image node_id 22 for calling a global function with example usage: test_ctor_with_datafile() without return types