def test_cache_purges_after_ttl():
mockdatetime = MockDatetime(datetime(2019, 4, 1, 10))
cache = ReadthroughTTLCache(timedelta(hours=2), lambda x: "payload")
with patch("datetime.datetime", mockdatetime):
cache.get("key_a", force_store=True)
# after one hour
mockdatetime.set_now(datetime(2019, 4, 1, 11))
cache.purge_expired_entries()
assert "key_a" in cache
# after two hours one minute
mockdatetime.set_now(datetime(2019, 4, 1, 12, 1))
cache.purge_expired_entries()
assert "key_a" not in cache
def test_doesnt_cache_unless_accessed_within_ttl():
mockdatetime = MockDatetime(datetime(2019, 4, 1, 10))
cache = ReadthroughTTLCache(timedelta(hours=4), lambda x: "payload")
with patch("datetime.datetime", mockdatetime):
cache.get("key_a")
# after one hour
mockdatetime.set_now(datetime(2019, 4, 1, 11))
assert "key_a" not in cache
# after two hours
mockdatetime.set_now(datetime(2019, 4, 1, 12))
cache.get("key_a")
# after three hours
mockdatetime.set_now(datetime(2019, 4, 1, 13))
assert "key_a" in cache
