'The result of ``get_device_path`` is cached after an ``attach_device``.'

def test_get_device_path_cached_after_attach(self):

    (attached_id1, attached_id2) = self.attached_volumes()
    path1 = self.cache.get_device_path(attached_id1)
    path2 = self.cache.get_device_path(attached_id2)
    path1again = self.cache.get_device_path(attached_id1)
    path2again = self.cache.get_device_path(attached_id2)
    self.assertEqual((path1again, path2again, (path1 == path2), self.counting_proxy.num_calls('get_device_path', attached_id1), self.counting_proxy.num_calls('get_device_path', attached_id2)), (path1, path2, False, 1, 1))
