'Expiration has no effect on the dummy cache'

def test_expiration(self):

    self.cache.set(u'expire1', u'very    quickly', 1)
    self.cache.set(u'expire2', u'very    quickly', 1)
    self.cache.set(u'expire3', u'very    quickly', 1)
    time.sleep(2)
    self.assertEqual(self.cache.get(u'expire1'), None)
    self.cache.add(u'expire2', u'newvalue')
    self.assertEqual(self.cache.get(u'expire2'), None)
    self.assertEqual(self.cache.has_key(u'expire3'), False)
