old_contents: 
  # -*- coding: utf-8 -*-
  from __future__ import (absolute_import, division, print_function,
                          unicode_literals)
  
  import unittest
  from grako.tool import genmodel
  
  
  class DiagramTests(unittest.TestCase):
  
      def test_dot(self):
          try:
              from grako.diagrams import draw
          except ImportError:
              return
  
          grammar = '''
              start = "foo\\nbar" $;
          '''
          m = genmodel('Diagram', grammar)
          draw('tmp/diagram.png', m)
  
  
  def suite():
      return unittest.TestLoader().loadTestsFromTestCase(DiagramTests)
  
  
  def main():
      unittest.TextTestRunner(verbosity=2).run(suite())
  
  if __name__ == '__main__':
      main()
  
new_contents: 
  # -*- coding: utf-8 -*-
  from __future__ import (absolute_import, division, print_function,
                          unicode_literals)
  
  import unittest
  from grako.tool import genmodel
  
  
  class DiagramTests(unittest.TestCase):
  
      def test_dot(self):
          grammar = '''
              start = "foo\\nbar" $;
          '''
          try:
              from grako.diagrams import draw
          except ImportError:
              return
  
          m = genmodel('Diagram', grammar)
          draw('tmp/diagram.png', m)
  
  
  def suite():
      return unittest.TestLoader().loadTestsFromTestCase(DiagramTests)
  
  
  def main():
      unittest.TextTestRunner(verbosity=2).run(suite())
  
  if __name__ == '__main__':
      main()
  
subject: Reorder unit test code.