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Reset Polyfactory's default random state on each test (#735)
Polyfactory keeps its own default `random.Random()` instance (`polyfactory.constants.DEFAULT_RANDOM`) separate from Faker's, so it wasn't being reseeded along with the other libraries pytest-randomly already supports. This adds Polyfactory to the same try/except reseed pattern used for factory_boy, Faker, Model Bakery, and NumPy, so factories using the default random generator get deterministic, per-test values under `--randomly-seed`. Factories that call `seed_random()` themselves are unaffected, same as before. Closes #720.
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‎CHANGELOG.rst‎

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@@ -7,6 +7,10 @@ Unreleased
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* Support Python 3.15.
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* Reset `Polyfactory <https://polyfactory.litestar.dev/>`__\’s default random state at the start of every test, if it is installed.
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Thanks to Rahul Kumar in `PR #735 <https://github.com/pytest-dev/pytest-randomly/issues/735>`__.
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* Switch package build backend from setuptools to `uv_build <https://docs.astral.sh/uv/concepts/build-backend/>`__.
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This makes builds with uv about nine times faster, since uv runs the backend natively, without creating a build environment or spawning a Python process.
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Additionally, source distributions no longer include test files, which setuptools previously included incompletely, missing the files needed to actually run them.

‎README.rst‎

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Only its `legacy random state <https://numpy.org/doc/stable/reference/random/legacy.html>`__ is affected.
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* `Polyfactory <https://polyfactory.litestar.dev/>`__
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Only the default random generator is affected.
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Factories that have called ``seed_random()`` with their own seed are unaffected.
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* If additional random generators are used, they can be registered under the
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``pytest_randomly.random_seeder``
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`entry point <https://packaging.python.org/specifications/entry-points/>`_ and

‎pyproject.toml‎

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"faker",
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"model-bakery>=1.13",
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"numpy",
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"polyfactory",
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"pytest>=9",
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"pytest-xdist",
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]

‎src/pytest_randomly/__init__.py‎

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except ImportError: # pragma: no cover
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have_numpy = False
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# polyfactory
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try:
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from polyfactory.constants import DEFAULT_RANDOM as polyfactory_random
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have_polyfactory = True
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except ImportError: # pragma: no cover
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# old versions
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try:
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from polyfactory.factories.base import BaseFactory
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polyfactory_random = BaseFactory.__random__
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have_polyfactory = True
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except ImportError:
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have_polyfactory = False
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def make_seed() -> int:
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return random.Random().getrandbits(32)
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if have_numpy: # pragma: no branch
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np_random.seed(seed % 2**32)
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if have_polyfactory: # pragma: no branch
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polyfactory_random.setstate(random_state)
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if entrypoint_reseeds is None:
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eps = entry_points(group="pytest_randomly.random_seeder")
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entrypoint_reseeds = [e.load() for e in eps]

‎tests/test_pytest_randomly.py‎

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out.assert_outcomes(passed=1)
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def test_polyfactory(ourtester):
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"""
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Check that Polyfactory's default random generator is reset between tests.
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Uses a Union-typed field so the assertion depends on
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DEFAULT_RANDOM.choice() picking which type to generate. A plain ``int``
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field wouldn't do: Polyfactory generates those via its Faker instance,
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whose random generator pytest-randomly already reseeds separately, so
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such a test would pass even without resetting DEFAULT_RANDOM.
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"""
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ourtester.makepyfile(
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test_one="""
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from dataclasses import dataclass
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from typing import Union
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from polyfactory.factories import DataclassFactory
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@dataclass
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class Foo:
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x: Union[int, str, float, bytes]
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class FooFactory(DataclassFactory[Foo]):
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pass
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def test_a():
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value = FooFactory.build().x
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assert isinstance(value, str)
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assert value == 'jKdWckZoDYuPmqHSsjBh'
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def test_b():
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value = FooFactory.build().x
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assert isinstance(value, int)
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assert value == 1908
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"""
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)
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out = ourtester.runpytest("--randomly-seed=1")
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out.assert_outcomes(passed=2)
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def test_failing_import(testdir):
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"""Test with pytest raising CollectError or ImportError.
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‎uv.lock‎

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