'Ensure is_null is handled correctly.'

def testIsNullLookups(self):

    Article.objects.create(title=u'I    Could    Go    Anywhere', content=u'Versatile', date=datetime.datetime.now())
    response = self.client.get((u'/test_admin/%s/admin_views/article/' % self.urlbit))
    self.assertContains(response, u'4    articles')
    response = self.client.get((u'/test_admin/%s/admin_views/article/' % self.urlbit), {u'section__isnull': u'false'})
    self.assertContains(response, u'3    articles')
    response = self.client.get((u'/test_admin/%s/admin_views/article/' % self.urlbit), {u'section__isnull': u'0'})
    self.assertContains(response, u'3    articles')
    response = self.client.get((u'/test_admin/%s/admin_views/article/' % self.urlbit), {u'section__isnull': u'true'})
    self.assertContains(response, u'1    article')
    response = self.client.get((u'/test_admin/%s/admin_views/article/' % self.urlbit), {u'section__isnull': u'1'})
    self.assertContains(response, u'1    article')
