class_docstr: Test class for cross-validation tests.
class_docstr_tok: ["Test","class","for","cross-validation","tests","."]
docstr: Create necessary directories for testing.
docstr_tok: ["Create","necessary","directories","for","testing","."]
code: def setUpClass(cls):
      """Create necessary directories for testing."""
      for dir_path in [train_dir, output_dir]:
          dir_path.mkdir(exist_ok=True)
  
      # create jsonlines feature files
      create_jsonlines_feature_files(train_dir)
  
imports: import csv
  import itertools
  import json
  import re
  import unittest
  import numpy
  from numpy.testing import assert_almost_equal
  from sklearn.datasets import make_classification
  from sklearn.feature_extraction import FeatureHasher
  from skll.config import load_cv_folds
  from skll.data import FeatureSet
  from skll.experiments import load_featureset, run_configuration
  from skll.learner import Learner
  from skll.utils.testing import compute_expected_folds_for_cv_testing, config_dir, create_jsonlines_feature_files, fill_in_config_paths_for_single_file, other_dir, output_dir, remove_jsonlines_feature_files, train_dir, unlink
label_desc: Use image node_id 1 for calling the TestCrossValidation obj's underlying member method code with example usage: obj.setUpClass(cls) without return types