class_docstr: Unit test class for testing scikit-learn converter.
code: def test_conversion_one_column(self):
      # Fit a single OHE
      scikit_model = OneHotEncoder()
      scikit_model.fit(self.scikit_data)
      spec = sklearn.convert(
          scikit_model, "single_feature", "out"
      ).get_spec()
  
      test_data = [{"single_feature": row} for row in self.scikit_data]
      scikit_output = [
          {"out": row}
          for row in scikit_model.transform(self.scikit_data).toarray()
      ]
      metrics = evaluate_transformer(spec, test_data, scikit_output)
  
      self.assertIsNotNone(spec)
      self.assertIsNotNone(spec.description)
      self.assertEqual(metrics["num_errors"], 0)
  
file_path: coremltools/coremltools/test/sklearn_tests/test_one_hot_encoder.py
imports: import unittest
  from copy import copy
  from distutils.version import StrictVersion
  import numpy
  from coremltools._deps import _HAS_SKLEARN, _SKLEARN_VERSION
  from coremltools.models.utils import _is_macos, _macos_version, evaluate_transformer
label_desc: Use image node_id 2 for calling the OneHotEncoderScikitTest obj's underlying member method code with example usage: obj.test_conversion_one_column() without return types