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Remove deprecated event_loop_policy fixture #1517

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a57d76a
feat!: Remove deprecated event_loop_policy fixture.
seifertm Jul 21, 2026
2ac8576
refactor: Simplify and rename _temporary_event_loop_policy.
seifertm Jul 21, 2026
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1 change: 1 addition & 0 deletions changelog.d/1517.removed.rst
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@@ -0,0 +1 @@
Deprecated *event_loop_policy* fixture
1 change: 0 additions & 1 deletion docs/how-to-guides/index.rst
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Expand Up @@ -16,7 +16,6 @@ How-To Guides
run_class_tests_in_same_loop
run_module_tests_in_same_loop
run_package_tests_in_same_loop
multiple_loops
parametrize_with_asyncio
uvloop
test_item_is_async
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14 changes: 0 additions & 14 deletions docs/how-to-guides/multiple_loops.rst
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29 changes: 0 additions & 29 deletions docs/how-to-guides/multiple_loops_example.py
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21 changes: 0 additions & 21 deletions docs/how-to-guides/uvloop.rst
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Expand Up @@ -18,24 +18,3 @@ Define a ``pytest_asyncio_loop_factories`` hook in your *conftest.py* that maps

:doc:`custom_loop_factory`
More details on the ``pytest_asyncio_loop_factories`` hook, including per-test factory selection and multiple factory parametrization.

Using the event_loop_policy fixture
-----------------------------------

.. note::

``asyncio.AbstractEventLoopPolicy`` is deprecated as of Python 3.14 (removal planned for 3.16), and ``uvloop.EventLoopPolicy`` will be removed alongside it. Overriding the *event_loop_policy* fixture is also deprecated in pytest-asyncio. Prefer the hook approach above.

For older versions of Python and uvloop, you can override the *event_loop_policy* fixture in your *conftest.py:*

.. code-block:: python

import pytest
import uvloop


@pytest.fixture(scope="session")
def event_loop_policy():
return uvloop.EventLoopPolicy()

You may choose to limit the scope of the fixture to *package,* *module,* or *class,* if you only want a subset of your tests to run with uvloop.
23 changes: 0 additions & 23 deletions docs/reference/fixtures/event_loop_policy_example.py
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28 changes: 0 additions & 28 deletions docs/reference/fixtures/event_loop_policy_parametrized_example.py
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23 changes: 0 additions & 23 deletions docs/reference/fixtures/index.rst
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Expand Up @@ -2,29 +2,6 @@
Fixtures
========

event_loop_policy
=================

.. warning::

Overriding the *event_loop_policy* fixture is deprecated and will be removed in a future version of pytest-asyncio. Use the ``pytest_asyncio_loop_factories`` hook instead. See :doc:`../hooks` for details.

Returns the event loop policy used to create asyncio event loops.
The default return value is *asyncio.get_event_loop_policy().*

This fixture can be overridden when a different event loop policy should be used.

.. include:: event_loop_policy_example.py
:code: python

Multiple policies can be provided via fixture parameters.
The fixture is automatically applied to all pytest-asyncio tests.
Therefore, all tests managed by pytest-asyncio are run once for each fixture parameter.
The following example runs the test with different event loop policies.

.. include:: event_loop_policy_parametrized_example.py
:code: python

unused_tcp_port
===============
Finds and yields a single unused TCP port on the localhost interface. Useful for
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28 changes: 2 additions & 26 deletions pytest_asyncio/plugin.py
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Expand Up @@ -805,11 +805,8 @@ def _temporary_event_loop(loop: AbstractEventLoop) -> Iterator[None]:


@contextlib.contextmanager
def _temporary_event_loop_policy(
policy: AbstractEventLoopPolicy,
) -> Iterator[None]:
def _restore_event_loop_policy() -> Iterator[None]:

@edgarrmondragon edgarrmondragon Aug 14, 2026 •
edited
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Should this context manager be outright removed? It still calls deprecated/removed APIs and all tests under Python 3.14 and 3.16 pass when I don't use it in _create_scoped_runner_fixture.

@tjkuson tjkuson Aug 14, 2026 •
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We discussed this offline at the pytest sprint. I think there are merits to either approach.

The idea was that code under test might apply an event loop policy which will need to be restored between tests even if we remove support for configuring the policy via the pytest-asyncio fixture. If we remove policy restoration context manager, users who depend on event loop policy being reset between tests could see confusing errors when upgrading to this new version (independent of the deprecated loop policy fixture being removed).

However, getting a warning about the deprecated API even after we ostensibly remove support for it is also a bad user experience. It might be strong enough reason to remove the support for event loop policies entirely.

If we remove both the fixture and the feature of the plugin that reset the policy between tests, then we'd need to communicate to users that both the fixture and support for testing code that sets an event loop policy are unsupported in v2.

@edgarrmondragon edgarrmondragon Aug 14, 2026 •
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Thanks for the context! So perhaps there is a compromise where the current policy is guarded and restored only on Python < 3.16, since users won't presumably be able to apply any policies on 3.16+ anyway. But perhaps that's thinking way too ahead of time.

old_loop_policy = _get_event_loop_policy()
_set_event_loop_policy(policy)
try:
yield
finally:
Expand Down Expand Up @@ -910,13 +907,6 @@ def inner(*args, **kwargs):

@pytest.hookimpl(wrapper=True)
def pytest_fixture_setup(fixturedef: FixtureDef, request) -> object | None:
if (
fixturedef.argname == "event_loop_policy"
and fixturedef.func.__module__ != __name__
):
warnings.warn(
PytestDeprecationWarning(_EVENT_LOOP_POLICY_FIXTURE_DEPRECATION_WARNING),
)
asyncio_mode = _get_asyncio_mode(request.config)
if not _is_asyncio_fixture_function(fixturedef.func):
if asyncio_mode == Mode.STRICT:
Expand Down Expand Up @@ -960,12 +950,6 @@ def pytest_fixture_setup(fixturedef: FixtureDef, request) -> object | None:
mark.asyncio 'loop_factories' must be a non-empty sequence of strings.
"""

_EVENT_LOOP_POLICY_FIXTURE_DEPRECATION_WARNING = """\
Overriding the "event_loop_policy" fixture is deprecated \
and will be removed in a future version of pytest-asyncio. \
Use the "pytest_asyncio_loop_factories" hook to customize event loop creation.\
"""


def _parse_asyncio_marker(
asyncio_marker: Mark,
Expand Down Expand Up @@ -1027,13 +1011,11 @@ def _create_scoped_runner_fixture(scope: _ScopeName) -> Callable:
name=f"_{scope}_scoped_runner",
)
def _scoped_runner(
event_loop_policy,
_asyncio_loop_factory,
request: FixtureRequest,
) -> Iterator[Runner]:
new_loop_policy = event_loop_policy
debug_mode = _get_asyncio_debug(request.config)
with _temporary_event_loop_policy(new_loop_policy):
with _restore_event_loop_policy():
runner = Runner(
debug=debug_mode,
loop_factory=_asyncio_loop_factory,
Expand Down Expand Up @@ -1074,12 +1056,6 @@ def _asyncio_loop_factory(request: FixtureRequest) -> LoopFactory | None:
return getattr(request, "param", None)


@pytest.fixture(scope="session", autouse=True)
def event_loop_policy() -> AbstractEventLoopPolicy:
"""Return an instance of the policy used to create asyncio event loops."""
return _get_event_loop_policy()


def is_async_test(item: Item) -> TypeIs[PytestAsyncioFunction]:
"""Returns whether a test item is a pytest-asyncio test"""
return isinstance(item, PytestAsyncioFunction)
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78 changes: 0 additions & 78 deletions tests/markers/test_class_scope.py
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Expand Up @@ -3,7 +3,6 @@
from __future__ import annotations

import asyncio
import sys
from textwrap import dedent

import pytest
Expand Down Expand Up @@ -98,83 +97,6 @@ async def test_this_runs_in_same_loop(self):
result.assert_outcomes(passed=2)


def test_asyncio_mark_respects_the_loop_policy(
pytester: pytest.Pytester,
):
pytester.makeini("[pytest]\nasyncio_default_fixture_loop_scope = function")
pytester.makepyfile(dedent("""\
import asyncio
import pytest

class CustomEventLoopPolicy(asyncio.DefaultEventLoopPolicy):
pass

class TestUsesCustomEventLoop:
@pytest.fixture(scope="class")
@classmethod
def event_loop_policy(cls):
return CustomEventLoopPolicy()

@pytest.mark.asyncio
async def test_uses_custom_event_loop_policy(self):
assert isinstance(
asyncio.get_event_loop_policy(),
CustomEventLoopPolicy,
)

@pytest.mark.asyncio
async def test_does_not_use_custom_event_loop_policy():
assert not isinstance(
asyncio.get_event_loop_policy(),
CustomEventLoopPolicy,
)
"""))
pytest_args = ["--asyncio-mode=strict"]
if sys.version_info >= (3, 14):
pytest_args.extend(["-W", "default"])
result = pytester.runpytest(*pytest_args)
if sys.version_info >= (3, 14):
result.assert_outcomes(passed=2, warnings=4)
result.stdout.fnmatch_lines("*DefaultEventLoopPolicy*")
else:
result.assert_outcomes(passed=2)


def test_asyncio_mark_respects_parametrized_loop_policies(
pytester: pytest.Pytester,
):
pytester.makeini("[pytest]\nasyncio_default_fixture_loop_scope = function")
pytester.makepyfile(dedent("""\
import asyncio

import pytest

@pytest.fixture(
scope="class",
params=[
asyncio.DefaultEventLoopPolicy(),
asyncio.DefaultEventLoopPolicy(),
]
)
def event_loop_policy(request):
return request.param

@pytest.mark.asyncio(loop_scope="class")
class TestWithDifferentLoopPolicies:
async def test_parametrized_loop(self, request):
pass
"""))
pytest_args = ["--asyncio-mode=strict"]
if sys.version_info >= (3, 14):
pytest_args.extend(["-W", "default"])
result = pytester.runpytest(*pytest_args)
if sys.version_info >= (3, 14):
result.assert_outcomes(passed=2, warnings=4)
result.stdout.fnmatch_lines("*DefaultEventLoopPolicy*")
else:
result.assert_outcomes(passed=2)


def test_asyncio_mark_provides_class_scoped_loop_to_fixtures(
pytester: pytest.Pytester,
):
Expand Down
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