new_contents: import unittest
  from number_to_words import NumberToWords
  
  
  class TestNumberToWords(unittest.TestCase):
      def setUp(self):
          self.n2w = NumberToWords()
  
      def tearDown(self):
          self.n2w = None
  
  if __name__ == '__main__':
      unittest.main()
  
subject: Set up test case