def test_compute_instance_id(self):
        initial = self.cache.compute_instance_id()
        later = [self.cache.compute_instance_id() for _ in range(10)]
        self.assertEqual(
            (later, self.counting_proxy.num_calls("compute_instance_id")),
            ([initial] * 10, 1))
The result of ``compute_instance_id`` is cached indefinitely.
dataset/ETHPy150Open ClusterHQ/flocker/flocker/node/agents/test/test_blockdevice.py/ProcessLifetimeCacheTests.test_compute_instance_id