new_contents: import string
  import random
  import collections
  
  from django.test import TestCase                         
  
  import comment_client
  import django.http
  import django_comment_client.middleware as middleware
  
  class AjaxExceptionTestCase(TestCase):
  
  # TODO: check whether the correct error message is produced. 
  # The error message should be the same as the argument to CommentClientError
  	def setUp(self):
  		self.a = middleware.AjaxExceptionMiddleware()
  		self.request1 = django.http.HttpRequest()
  		self.request0 = django.http.HttpRequest()
  		self.exception1 = comment_client.CommentClientError('{}')
  		self.exception0 = ValueError()
  		self.request1.META['HTTP_X_REQUESTED_WITH'] = "XMLHttpRequest"
  		self.request0.META['HTTP_X_REQUESTED_WITH'] = "SHADOWFAX"
  		
  	def test_process_exception(self):
  		self.assertIsInstance(self.a.process_exception(self.request1, self.exception1), middleware.JsonError)
  		self.assertIsNone(self.a.process_exception(self.request1, self.exception0))
  		self.assertIsNone(self.a.process_exception(self.request0, self.exception1))
  		self.assertIsNone(self.a.process_exception(self.request0, self.exception0))
  
subject: Add tests for diango-comment-client middleware