def test_get_redis_cache(self, redis_cache_mock, fallback_cache_mock):
"""Test that redis_cache is used by default."""
client = RedisCacheWithFallback(None, {})
client.get("irrelevent")
redis_cache_mock.assert_called_once()
fallback_cache_mock.assert_not_called()
def test_get_fallback_cache(self, redis_cache_mock, fallback_cache_mock,
logger_mock):
"""
Test case when redis_cache raises an exception,
logger logs the exception then fallback_cache takes over
"""
client = RedisCacheWithFallback(None, {})
client.get("irrelevent")
redis_cache_mock.assert_called_once()
fallback_cache_mock.assert_not_called()
redis_cache_mock.side_effect = Exception()
client.get("irrelevent")
logger_mock.warning.assert_called_with(
"[DEGRADED CACHE MODE] - Switch to fallback cache")
logger_mock.exception.assert_called_once()
fallback_cache_mock.assert_called_once()
def test_invalidate_fallback_cache(self, redis_cache_mock, delete_mock):
"""
Test that fallback_cache is invalidated every 60 seconds
when Redis is up
"""
now = datetime.datetime.now()
client = RedisCacheWithFallback(None, {})
client.get("round_0")
redis_cache_mock.reset_mock()
delete_mock.reset_mock()
# A second cache access should not delete the fallback cache again
client.get("round_1")
redis_cache_mock.assert_called_once()
delete_mock.assert_not_called()
redis_cache_mock.reset_mock()
delete_mock.reset_mock()
# Another call to Redis cache 120 seconds later
# should delete the fallback cache again
read_time = now + datetime.timedelta(seconds=120)
with mock.patch("base.utils.datetime") as mock_datetime:
mock_datetime.now.return_value = read_time
client.get("round_2")
redis_cache_mock.assert_called_once()
delete_mock.assert_called_once()
redis_cache_mock.reset_mock()
delete_mock.reset_mock()
# Another call to Redis cache 30 seconds later (<1 minute)
# should not delete the fallback cache again
read_time += datetime.timedelta(seconds=30)
with mock.patch("base.utils.datetime") as mock_datetime:
mock_datetime.now.return_value = read_time
client.get("round_3")
redis_cache_mock.assert_called_once()
delete_mock.assert_not_called()
redis_cache_mock.reset_mock()
delete_mock.reset_mock()
# Another call to Redis cache exactly 1 minute after
# the latest call should not delete the fallback cache again
read_time += datetime.timedelta(seconds=30)
with mock.patch("base.utils.datetime") as mock_datetime:
mock_datetime.now.return_value = read_time
client.get("round_4")
redis_cache_mock.assert_called_once()
delete_mock.assert_not_called()
redis_cache_mock.reset_mock()
delete_mock.reset_mock()
# Another call to Redis cache exactly 1 minute and 1 second after
# the latest call should delete the fallback cache again
read_time += datetime.timedelta(seconds=1)
with mock.patch("base.utils.datetime") as mock_datetime:
mock_datetime.now.return_value = read_time
client.get("round_5")
redis_cache_mock.assert_called_once()
delete_mock.assert_called_once()
redis_cache_mock.reset_mock()
delete_mock.reset_mock()
def test_client(self):
"""Test class instance of caches"""
client = RedisCacheWithFallback(None, {})
self.assertIs(type(client), RedisCacheWithFallback)
self.assertIs(type(client._redis_cache), RedisCache)
self.assertIs(type(client._fallback_cache), DummyCache)