def METHOD_NAME(self):
    backend = RedisBackend(capacity=2, truncation_chance=1.0)
    records = [Record(f"record:{i}", "value", time.time()) for i in range(4)]
    for record in records:
        backend.add("timeline", record)
    with backend.digest("timeline", 0) as records:
        assert set(records) == set(records[-2:])