The post_generated
decorator#
The post_generated
decorator wraps a classmethod
into a
PostGenerated
field. This is useful when the post generated field depends
on the current factory, usually its __faker__
and/or __random__
attribute. For example:
from dataclasses import dataclass, field
from datetime import datetime, timedelta
from typing import cast
from polyfactory.decorators import post_generated
from polyfactory.factories import DataclassFactory
@dataclass
class DatetimeRange:
to_dt: datetime
from_dt: datetime = field(default_factory=datetime.now)
class DatetimeRangeFactory(DataclassFactory[DatetimeRange]):
@post_generated
@classmethod
def to_dt(cls, from_dt: datetime) -> datetime:
return from_dt + cast(timedelta, cls.__faker__.time_delta("+3d"))
def test_post_generated() -> None:
date_range_instance = DatetimeRangeFactory.build()
assert date_range_instance.to_dt > date_range_instance.from_dt
assert date_range_instance.to_dt < date_range_instance.from_dt + timedelta(days=3)
All classmethod parameters after cls
must be named as the fields this post generated field depends on.