Does not mock time for TTLCache

[irusland]

Hey, I've recently encountered the problem with freezing the time in TTLCache

Steps to reproduce

import time
from datetime import timedelta

from cachetools import TTLCache
from freezegun import freeze_time

with freeze_time() as frozen_datetime:
    ttl = TTLCache(
        maxsize=10, ttl=1,
        # timer=time.monotonic,  # uncomment this to pass assertion
    )
    ttl.update({'1': 1})
    assert ttl.keys()
    frozen_datetime.tick(timedelta(seconds=10000))
    assert not ttl.keys()

The problem with that is when use reference as a function parameter it caches timer=time.monotonic in defaults so freeze gun does not override it

Is there a way to overcome this?

Ive come up with the solution as overriding the standard ttlcache like so

import time

from cachetools import TTLCache as TTLCacheBase


class TTLCache(TTLCacheBase):
    def __init__(self, maxsize, ttl, timer=None, getsizeof=None):
        if timer is None:
            timer = time.monotonic
        super().__init__(maxsize=maxsize, ttl=ttl, timer=timer, getsizeof=getsizeof)

[POD666]

Same:

In [1]: from freezegun import freeze_time
In [2]: from datetime import datetime, timedelta
In [3]: from cachetools.func import ttl_cache
In [4]: @ttl_cache(ttl=100)
   ...: def now():
   ...:     return datetime.now()
In [5]: import time
In [6]: timer = time.monotonic
In [7]: print(timer())
   ...: print(now())
   ...: with freeze_time(timedelta(days=4), tick=True):
   ...:     print(timer())
   ...:     print(now())
   ...:     print(timer())
61.09706311
2022-11-17 12:51:30.917532
1669027890.946961
2022-11-17 12:51:30.917532
1669027890.947039

[ylhan]

+1 I'm running into this too. It's making ttl_cache impossible to test elegantly.

[RonnyPfannschmidt]

to solve this cachetools would have to stop memoizing pre-patching time functions in the factories

https://github.com/tkem/cachetools/blob/d991ac71b4eb6394be5ec572b835434081393215/src/cachetools/func.py#L107