'Objects are updated by first filtering the candidates into a queryset
and then calling the update() method. It executes immediately and
returns nothing.'

def test_update(self):

    resp = DataPoint.objects.filter(value=u'apple').update(name=u'd1')
    self.assertEqual(resp, 1)
    resp = DataPoint.objects.filter(value=u'apple')
    self.assertEqual(list(resp), [self.d0])
