class_docstr: Test class for custom learner tests.
class_docstr_tok: ["Test","class","for","custom","learner","tests","."]
code: def test_custom_learner_api_bad_extension(self):
      with self.assertRaises(ValueError):
          _ = Learner(
              "_CustomLogisticRegressionWrapper",
              custom_learner_path=str(other_dir / "custom_learner.txt"),
          )
  
file_path: skll/tests/test_custom_learner.py
imports: import csv
  import unittest
  from itertools import chain
  import numpy
  from numpy.testing import assert_array_equal
  from skll.data import NDJWriter
  from skll.experiments import run_configuration
  from skll.learner import Learner
  from skll.utils.testing import config_dir, fill_in_config_paths, make_classification_data, other_dir, output_dir, test_dir, train_dir, unlink
label_desc: Use image node_id 8 for calling the TestCustomLearner obj's underlying member method code with example usage: obj.test_custom_learner_api_bad_extension() without return types