[fix] Prevent DeprecationWarning from bubbling to user code.

Signed-off-by: Michael Seifert <m.seifert@digitalernachschub.de>

docs/source/reference/changelog.rst

@@ -2,10 +2,11 @@
 Changelog
 =========
 
-0.23.5 (UNRELEASED)
+0.23.5 (2024-02-09)
 ===================
 - Declare compatibility with pytest 8 `#737 <https://github.com/pytest-dev/pytest-asyncio/issues/737>`_
 - Fix typing errors with recent versions of mypy `#769 <https://github.com/pytest-dev/pytest-asyncio/issues/769>`_
+- Prevent DeprecationWarning about internal use of `asyncio.get_event_loop()` from affecting test cases `#757 <https://github.com/pytest-dev/pytest-asyncio/issues/757>`_
 
 Known issues
 ------------

pytest_asyncio/plugin.py

@@ -667,7 +667,9 @@ def _removesuffix(s: str, suffix: str) -> str:
 def _temporary_event_loop_policy(policy: AbstractEventLoopPolicy) -> Iterator[None]:
     old_loop_policy = asyncio.get_event_loop_policy()
     try:
-        old_loop = asyncio.get_event_loop()
+        with warnings.catch_warnings():
+            warnings.simplefilter("ignore", DeprecationWarning)
+            old_loop = asyncio.get_event_loop()
     except RuntimeError:
         old_loop = None
     asyncio.set_event_loop_policy(policy)

tests/markers/test_class_scope.py

@@ -287,3 +287,22 @@ async def test_does_not_fail(self, sets_event_loop_to_none, n):
     )
     result = pytester.runpytest("--asyncio-mode=strict")
     result.assert_outcomes(passed=2)
+
+
+def test_standalone_test_does_not_trigger_warning_about_no_current_event_loop_being_set(
+    pytester: pytest.Pytester,
+):
+    pytester.makepyfile(
+        dedent(
+            """\
+            import pytest
+
+            @pytest.mark.asyncio(scope="class")
+            class TestClass:
+                async def test_anything(self):
+                    pass
+            """
+        )
+    )
+    result = pytester.runpytest_subprocess("--asyncio-mode=strict")
+    result.assert_outcomes(warnings=0, passed=1)

tests/markers/test_function_scope.py

@@ -179,3 +179,21 @@ async def test_does_not_fail(sets_event_loop_to_none, n):
     )
     result = pytester.runpytest("--asyncio-mode=strict")
     result.assert_outcomes(passed=2)
+
+
+def test_standalone_test_does_not_trigger_warning_about_no_current_event_loop_being_set(
+    pytester: Pytester,
+):
+    pytester.makepyfile(
+        dedent(
+            """\
+            import pytest
+
+            @pytest.mark.asyncio
+            async def test_anything():
+                pass
+            """
+        )
+    )
+    result = pytester.runpytest_subprocess("--asyncio-mode=strict")
+    result.assert_outcomes(warnings=0, passed=1)

tests/markers/test_module_scope.py

@@ -344,3 +344,21 @@ async def test_does_not_fail(sets_event_loop_to_none, n):
     )
     result = pytester.runpytest("--asyncio-mode=strict")
     result.assert_outcomes(passed=2)
+
+
+def test_standalone_test_does_not_trigger_warning_about_no_current_event_loop_being_set(
+    pytester: Pytester,
+):
+    pytester.makepyfile(
+        dedent(
+            """\
+            import pytest
+
+            @pytest.mark.asyncio(scope="module")
+            async def test_anything():
+                pass
+            """
+        )
+    )
+    result = pytester.runpytest_subprocess("--asyncio-mode=strict")
+    result.assert_outcomes(warnings=0, passed=1)

tests/markers/test_package_scope.py

@@ -350,3 +350,22 @@ async def test_does_not_fail(sets_event_loop_to_none, n):
     )
     result = pytester.runpytest("--asyncio-mode=strict")
     result.assert_outcomes(passed=2)
+
+
+def test_standalone_test_does_not_trigger_warning_about_no_current_event_loop_being_set(
+    pytester: Pytester,
+):
+    pytester.makepyfile(
+        __init__="",
+        test_module=dedent(
+            """\
+            import pytest
+
+            @pytest.mark.asyncio(scope="package")
+            async def test_anything():
+                pass
+            """
+        ),
+    )
+    result = pytester.runpytest_subprocess("--asyncio-mode=strict")
+    result.assert_outcomes(warnings=0, passed=1)

tests/markers/test_session_scope.py

@@ -415,3 +415,21 @@ async def test_does_not_fail(sets_event_loop_to_none, n):
     )
     result = pytester.runpytest("--asyncio-mode=strict")
     result.assert_outcomes(passed=2)
+
+
+def test_standalone_test_does_not_trigger_warning_about_no_current_event_loop_being_set(
+    pytester: Pytester,
+):
+    pytester.makepyfile(
+        dedent(
+            """\
+            import pytest
+
+            @pytest.mark.asyncio(scope="session")
+            async def test_anything():
+                pass
+            """
+        )
+    )
+    result = pytester.runpytest_subprocess("--asyncio-mode=strict")
+    result.assert_outcomes(warnings=0, passed=1)