'Ensure is_null is handled correctly.'

def testIsNullLookups(self):

    Article.objects.create(title='I    Could    Go    Anywhere', content='Versatile', date=datetime.datetime.now())
    response = self.client.get(('/test_admin/%s/admin_views/article/' % self.urlbit))
    self.assertTrue(('4    articles' in response.content), '"4    articles"    missing    from    response')
    response = self.client.get(('/test_admin/%s/admin_views/article/' % self.urlbit), {'section__isnull': 'false'})
    self.assertTrue(('3    articles' in response.content), '"3    articles"    missing    from    response')
    response = self.client.get(('/test_admin/%s/admin_views/article/' % self.urlbit), {'section__isnull': 'true'})
    self.assertTrue(('1    article' in response.content), '"1    article"    missing    from    response')
