new_contents: import unittest
  
  from scrubadub import exceptions
  
  
  class ExceptionsTestCase(unittest.TestCase):
      def test_render(self):
          exception = exceptions.ScrubadubException()
          exception.var = 'there'
  
          self.assertEquals(exception.render('test'), 'test')
          self.assertEquals(exception.render('url %(issues_url)s'), 'url ' + exception.issues_url)
          self.assertEquals(exception.render('hello %(var)s'), 'hello there')
  
subject: add an exceptions test to test the render function