'Ensure that Meta.ordering=None works the same as Meta.ordering=[]'

def test_ticket17429(self):

    original_ordering = Tag._meta.ordering
    Tag._meta.ordering = None
    try:
        self.assertQuerysetEqual(Tag.objects.all(), [u'<Tag:    t1>', u'<Tag:    t2>', u'<Tag:    t3>', u'<Tag:    t4>', u'<Tag:    t5>'], ordered=False)
    finally:
        Tag._meta.ordering = original_ordering
