new_contents: #!/usr/bin/env python
  
  import os
  import unittest
  
  def suite():
      suite = unittest.TestSuite()
      for _, _, files in os.walk('.'):
          for name in filter(is_test, files):
              tests = unittest.defaultTestLoader.loadTestsFromName(name[:-3])
              suite.addTests(tests)
      return suite
  
  def is_test(filename):
      return filename.startswith('test_') and filename.endswith('.py')
  
  if __name__ == "__main__":
      unittest.main(defaultTest="suite")
  
subject: Add test_all script