time_machine.travel doesn't work with Pydantic 2

[MrSampson]

Python Version

3.11.7

pytest Version

7.4.4

Package Version

2.14.1

Description

When using pydantic 2.6.4 Field default values, time machine.travel doesn't seem to have any affect.

import datetime as dt
import time_machine
from pydantic import BaseModel, Field

class Test(BaseModel):

    time: dt.datetime = Field(default=dt.datetime.now(), validate_default=True)

@time_machine.travel(dt.datetime(2020, 1, 10, 10, 30))
def test_init__default():
    result = Test()
    assert result.time == dt.datetime(2020, 1, 10, 10, 30)

After executing the test, the result.time will be the current system time.

[adamchainz]

You’re calling dt.datetime.now() at import time, which provides a set time to Pydantic. There’s no later function call for time-machine to patch. I think you instead want default_factory=dt.datetime.now (docs).

[MrSampson]

Thank you! I didn't even know that existed.