'Confirm evacuate scenario does not update host.'

def test_rebuild_with_wrong_shared_storage(self):

    with mock.patch.object(self.compute.driver, 'instance_on_disk', side_effect=(lambda x: True)) as mock_inst:
        self.assertRaises(exception.InvalidSharedStorage, (lambda : self._rebuild(on_shared_storage=False)))
        instance = db.instance_get(self.context, self.inst.id)
        self.assertEqual(instance['host'], 'fake_host_2')
        self.assertTrue(mock_inst.called)
