text: #!/usr/bin/env python
  
  import sklearn.feature_extraction as fe
  
  import pandas_ml as pdml
  import pandas_ml.util.testing as tm
  
  
  class TestFeatureExtraction(tm.TestCase):
  
      def test_objectmapper(self):
          df = pdml.ModelFrame([])
          self.assertIs(df.feature_extraction.DictVectorizer, fe.DictVectorizer)
          self.assertIs(df.feature_extraction.FeatureHasher, fe.FeatureHasher)
  
          self.assertIs(df.feature_extraction.image.img_to_graph, fe.image.img_to_graph)
          self.assertIs(df.feature_extraction.image.grid_to_graph, fe.image.grid_to_graph)
          self.assertIs(df.feature_extraction.image.extract_patches_2d, fe.image.extract_patches_2d)
          self.assertIs(df.feature_extraction.image.reconstruct_from_patches_2d,
                        fe.image.reconstruct_from_patches_2d)
          self.assertIs(df.feature_extraction.image.PatchExtractor, fe.image.PatchExtractor)
  
          self.assertIs(df.feature_extraction.text.CountVectorizer, fe.text.CountVectorizer)
          self.assertIs(df.feature_extraction.text.HashingVectorizer, fe.text.HashingVectorizer)
          self.assertIs(df.feature_extraction.text.TfidfTransformer, fe.text.TfidfTransformer)
          self.assertIs(df.feature_extraction.text.TfidfVectorizer, fe.text.TfidfVectorizer)
  