Freezing of custom datetime classes

[sliverc]

Custom date times are not frozen when using freeze_time.

Example:

from datetime import datetime
from freezegun import freeze_time

class CustomDatetime(datetime):
  pass

with freeze_time('2018-05-30'):
  print(datetime.now())   # correctly outputs 2018-05-30 00:00:00
  print(CustomDatetime.now())   # invalid output of current timestamp

I have encountered this issue when using faker library which uses a custom datetime.

[spulec]

Ah, I think this may have been a regression caused by https://github.com/spulec/freezegun/pull/175

It looks like we are checking the id of the module variables, but this won't catch subclasses: https://github.com/spulec/freezegun/blob/1a6c8144b1d5424fd140c93b247b564bd762cfdf/freezegun/api.py#L92-L93

[gradybarrett]

@spulec I bumped my version back to 0.3.10, and expected that to fix this based on your above comment and the timeframe that that fix got merged. Alas it didn't fix the issue.

Did I misread that merge timeline or was this use case never supported by freezegun?