old_contents: #!/usr/bin/env python
  # -*- coding: utf-8 -*-
  
  import unittest
  
  from spam.preprocess import PreProcess
  from spam.common import params
  
  
  class TestPreProcess(unittest.TestCase):
      """
      Class for testing the preprocces.
      """
      def setUp(self):
          self.preprocess = PreProcess(
              params.DATASET_PATH,
              params.DATASET_SUBDIRS,
          )
  
      def tearDown(self):
          pass
  
      def test_preprocess_instance(self):
          """
          Test if preprocess is creating a instance.
          """
          self.assertIsInstance(self.preprocess, PreProcess)
  
new_contents: #!/usr/bin/env python
  # -*- coding: utf-8 -*-
  
  import unittest
  
  from spam.preprocess import PreProcess
  from spam.common import params
  
  
  class TestPreProcess(unittest.TestCase):
      """
      Class for testing the preprocces.
      """
      def setUp(self):
          self.preprocess = PreProcess(
              params.DATASET_PATH,
              params.DATASET_SUBDIRS,
          )
  
      def tearDown(self):
          pass
  
      def test_preprocess_instance(self):
          """
          Test if preprocess is creating a instance.
          """
          self.assertIsInstance(self.preprocess, PreProcess)
  
      def test_preprocess_open_email(self):
          """
          Test if preprocess can open email from the dataset.
          """
          pass
  
      def test_preprocess_read_email(self):
          """
          Test if preprocess can read email from the dataset.
          """
          pass
  
      def test_preprocess_regex_email(self):
          """
          Test if preprocess regex can remove non-alphanumeric
          characters and the word `Subject:` and replace it with a space.
          """
          pass
  
      def test_preprocess_tokenize_email(self):
          """
          Test if preprocess can tokenize email.
          """
          pass
  
      def test_preprocess_stopwords(self):
          """
          Test if preprocess can remove stopwords.
          """
          pass
  
      def test_preprocess_clean_email(self):
          """
          Test of preprocess can clean a email.
          This involves replacing characters via regex,
          tokenizing, and removing stopwords.
          """
          pass
  
      def test_preprocess_bag_of_words(self):
          """
          Test if preprocess can produces a correct bag-of-words.
          """
          pass
  
subject: Add empty tests with descriptions.