WIP: Introduce event_loop_policy fixture.

Signed-off-by: Michael Seifert <[email protected]>

Author: seifertm

docs/source/reference/markers/class_scoped_loop_custom_policies_strict_mode_example.py

@@ -3,12 +3,16 @@
 import pytest
 
 
-@pytest.mark.asyncio_event_loop(
-    policy=[
+@pytest.fixture(
+    params=[
         asyncio.DefaultEventLoopPolicy(),
         asyncio.DefaultEventLoopPolicy(),
     ]
 )
+def event_loop_policy(request):
+    return request.param
+
+
 class TestWithDifferentLoopPolicies:
     @pytest.mark.asyncio
     async def test_parametrized_loop(self):

docs/source/reference/markers/class_scoped_loop_custom_policy_strict_mode_example.py

@@ -7,7 +7,12 @@ class CustomEventLoopPolicy(asyncio.DefaultEventLoopPolicy):
     pass
 
 
-@pytest.mark.asyncio_event_loop(policy=CustomEventLoopPolicy())
+@pytest.fixture(scope="class")
+def event_loop_policy(request):
+    return CustomEventLoopPolicy()
+
+
+@pytest.mark.asyncio_event_loop
 class TestUsesCustomEventLoopPolicy:
     @pytest.mark.asyncio
     async def test_uses_custom_event_loop_policy(self):

pytest_asyncio/plugin.py

@@ -6,6 +6,7 @@
 import inspect
 import socket
 import warnings
+from asyncio import AbstractEventLoopPolicy
 from textwrap import dedent
 from typing import (
     Any,
@@ -553,12 +554,6 @@ def pytest_collectstart(collector: pytest.Collector):
     for mark in marks:
         if not mark.name == "asyncio_event_loop":
             continue
-        event_loop_policy = mark.kwargs.get("policy", asyncio.get_event_loop_policy())
-        policy_params = (
-            event_loop_policy
-            if isinstance(event_loop_policy, Iterable)
-            else (event_loop_policy,)
-        )
 
         # There seem to be issues when a fixture is shadowed by another fixture
         # and both differ in their params.
@@ -573,14 +568,12 @@ def pytest_collectstart(collector: pytest.Collector):
         @pytest.fixture(
             scope="class" if isinstance(collector, pytest.Class) else "module",
             name=event_loop_fixture_id,
-            params=policy_params,
-            ids=tuple(type(policy).__name__ for policy in policy_params),
         )
         def scoped_event_loop(
             *args,  # Function needs to accept "cls" when collected by pytest.Class
-            request,
+            event_loop_policy,
         ) -> Iterator[asyncio.AbstractEventLoop]:
-            new_loop_policy = request.param
+            new_loop_policy = event_loop_policy
             old_loop_policy = asyncio.get_event_loop_policy()
             old_loop = asyncio.get_event_loop()
             asyncio.set_event_loop_policy(new_loop_policy)
@@ -867,6 +860,12 @@ def event_loop(request: FixtureRequest) -> Iterator[asyncio.AbstractEventLoop]:
     loop.close()
 
 
+@pytest.fixture(scope="session", autouse=True)
+def event_loop_policy() -> AbstractEventLoopPolicy:
+    """Return an instance of the policy used to create asyncio event loop."""
+    return asyncio.get_event_loop_policy()
+
+
 def _unused_port(socket_type: int) -> int:
     """Find an unused localhost port from 1024-65535 and return it."""
     with contextlib.closing(socket.socket(type=socket_type)) as sock:

tests/markers/test_class_marker.py

@@ -140,8 +140,12 @@ def test_asyncio_event_loop_mark_allows_specifying_the_loop_policy(
             class CustomEventLoopPolicy(asyncio.DefaultEventLoopPolicy):
                 pass
 
-            @pytest.mark.asyncio_event_loop(policy=CustomEventLoopPolicy())
-            class TestUsesCustomEventLoopPolicy:
+            @pytest.fixture(scope="class")
+            def event_loop_policy():
+                return CustomEventLoopPolicy()
+
+            @pytest.mark.asyncio_event_loop
+            class TestUsesCustomEventLoop:
 
                 @pytest.mark.asyncio
                 async def test_uses_custom_event_loop_policy(self):
@@ -173,15 +177,18 @@ def test_asyncio_event_loop_mark_allows_specifying_multiple_loop_policies(
 
             import pytest
 
-            @pytest.mark.asyncio_event_loop(
-                policy=[
+            @pytest.fixture(
+                params=[
                     asyncio.DefaultEventLoopPolicy(),
                     asyncio.DefaultEventLoopPolicy(),
                 ]
             )
+            def event_loop_policy(request):
+                return request.param
+
             class TestWithDifferentLoopPolicies:
                 @pytest.mark.asyncio
-                async def test_parametrized_loop(self):
+                async def test_parametrized_loop(self, request):
                     pass
             """
         )

tests/markers/test_module_marker.py

@@ -157,7 +157,11 @@ class CustomEventLoopPolicy(asyncio.DefaultEventLoopPolicy):
 
             from .custom_policy import CustomEventLoopPolicy
 
-            pytestmark = pytest.mark.asyncio_event_loop(policy=CustomEventLoopPolicy())
+            pytestmark = pytest.mark.asyncio_event_loop
+
+            @pytest.fixture(scope="module")
+            def event_loop_policy():
+                return CustomEventLoopPolicy()
 
             @pytest.mark.asyncio
             async def test_uses_custom_event_loop_policy():
@@ -178,7 +182,7 @@ async def test_uses_custom_event_loop_policy():
             async def test_does_not_use_custom_event_loop_policy():
                 assert not isinstance(
                     asyncio.get_event_loop_policy(),
-                   CustomEventLoopPolicy,
+                    CustomEventLoopPolicy,
                 )
             """
         ),
@@ -197,20 +201,25 @@ def test_asyncio_event_loop_mark_allows_specifying_multiple_loop_policies(
 
             import pytest
 
-            pytestmark = pytest.mark.asyncio_event_loop(
-                policy=[
+            pytestmark = pytest.mark.asyncio_event_loop
+
+            @pytest.fixture(
+                scope="module",
+                params=[
                     asyncio.DefaultEventLoopPolicy(),
                     asyncio.DefaultEventLoopPolicy(),
-                ]
+                ],
             )
+            def event_loop_policy(request):
+                return request.param
 
             @pytest.mark.asyncio
             async def test_parametrized_loop():
                 pass
             """
         )
     )
-    result = pytester.runpytest_subprocess("--asyncio-mode=strict")
+    result = pytester.runpytest_subprocess("--asyncio-mode=strict", "--setup-show")
     result.assert_outcomes(passed=2)