Reset Polyfactory's random state on each test

CHANGELOG.rst

@@ -2,6 +2,10 @@
 Changelog
 =========
 
+* Reset `Polyfactory <https://polyfactory.litestar.dev/>`__’s default random state at the start of every test, if it is installed.
+
+  Thanks to davidszotten for the request in `Issue #720 <https://github.com/pytest-dev/pytest-randomly/issues/720>`__.
+
 4.1.0 (2026-04-20)
 ------------------
 

README.rst

@@ -64,6 +64,11 @@ All of these features are on by default but can be disabled with flags.
 
     Only its `legacy random state <https://numpy.org/doc/stable/reference/random/legacy.html>`__ is affected.
 
+  * `Polyfactory <https://polyfactory.litestar.dev/>`__
+
+    Only the default random generator is affected. Factories that have called
+    ``seed_random()`` with their own seed are unaffected.
+
 * If additional random generators are used, they can be registered under the
   ``pytest_randomly.random_seeder``
   `entry point <https://packaging.python.org/specifications/entry-points/>`_ and

pyproject.toml

@@ -50,6 +50,7 @@ test = [
   "faker",
   "model-bakery>=1.13",
   "numpy",
+  "polyfactory",
   "pytest>=9",
   "pytest-xdist",
 ]

src/pytest_randomly/__init__.py

@@ -54,6 +54,14 @@
 except ImportError:  # pragma: no cover
     have_numpy = False
 
+# polyfactory
+try:
+    from polyfactory.constants import DEFAULT_RANDOM as polyfactory_random
+
+    have_polyfactory = True
+except ImportError:  # pragma: no cover
+    have_polyfactory = False
+
 
 def make_seed() -> int:
     return random.Random().getrandbits(32)
@@ -157,6 +165,9 @@ def _reseed(config: Config, offset: int = 0) -> int:
     if have_numpy:  # pragma: no branch
         np_random.seed(seed % 2**32)
 
+    if have_polyfactory:  # pragma: no branch
+        polyfactory_random.setstate(random_state)
+
     if entrypoint_reseeds is None:
         eps = entry_points(group="pytest_randomly.random_seeder")
         entrypoint_reseeds = [e.load() for e in eps]

tests/test_pytest_randomly.py

@@ -696,6 +696,50 @@ def test_one():
     out.assert_outcomes(passed=1)
 
 
+def test_polyfactory(ourtester):
+    """
+    Check that Polyfactory's default random generator is reset between tests.
+
+    Uses a Union-typed field so the assertion depends on
+    DEFAULT_RANDOM.choice() picking which type to generate. A plain ``int``
+    field wouldn't do: Polyfactory generates those via its Faker instance,
+    whose random generator pytest-randomly already reseeds separately, so
+    such a test would pass even without resetting DEFAULT_RANDOM.
+    """
+    ourtester.makepyfile(
+        test_one="""
+        from dataclasses import dataclass
+        from typing import Union
+
+        from polyfactory.factories import DataclassFactory
+
+
+        @dataclass
+        class Foo:
+            x: Union[int, str, float, bytes]
+
+
+        class FooFactory(DataclassFactory[Foo]):
+            __model__ = Foo
+
+
+        def test_a():
+            value = FooFactory.build().x
+            assert isinstance(value, str)
+            assert value == 'jKdWckZoDYuPmqHSsjBh'
+
+
+        def test_b():
+            value = FooFactory.build().x
+            assert isinstance(value, int)
+            assert value == 1908
+        """
+    )
+
+    out = ourtester.runpytest("--randomly-seed=1")
+    out.assert_outcomes(passed=2)
+
+
 def test_failing_import(testdir):
     """Test with pytest raising CollectError or ImportError.