Allow type narrowing with is_async_test

changelog.d/+167df28d.downstream.rst

@@ -0,0 +1 @@
+Extend dependency on typing-extensions>=4.12 from Python<3.10 to Python<3.13.

pyproject.toml

@@ -43,7 +43,7 @@ dynamic = [
 dependencies = [
   "backports-asyncio-runner>=1.1,<2; python_version<'3.11'",
   "pytest>=8.2,<9",
-  "typing-extensions>=4.12; python_version<'3.10'",
+  "typing-extensions>=4.12; python_version<'3.13'",
 ]
 optional-dependencies.docs = [
   "sphinx>=5.3",

pytest_asyncio/plugin.py

@@ -28,7 +28,6 @@
     Literal,
     TypeVar,
     Union,
-    cast,
     overload,
 )
 
@@ -60,6 +59,11 @@
 else:
     from backports.asyncio.runner import Runner
 
+if sys.version_info >= (3, 13):
+    from typing import TypeIs
+else:
+    from typing_extensions import TypeIs
+
 _ScopeName = Literal["session", "package", "module", "class", "function"]
 _R = TypeVar("_R", bound=Union[Awaitable[Any], AsyncIterator[Any]])
 _P = ParamSpec("_P")
@@ -628,14 +632,9 @@ def _set_event_loop(loop: AbstractEventLoop | None) -> None:
 
 @pytest.hookimpl(tryfirst=True, hookwrapper=True)
 def pytest_pyfunc_call(pyfuncitem: Function) -> object | None:
-    """
-    Pytest hook called before a test case is run.
-
-    Wraps marked tests in a synchronous function
-    where the wrapped test coroutine is executed in an event loop.
-    """
+    """Pytest hook called before a test case is run."""
     if pyfuncitem.get_closest_marker("asyncio") is not None:
-        if isinstance(pyfuncitem, PytestAsyncioFunction):
+        if is_async_test(pyfuncitem):
             asyncio_mode = _get_asyncio_mode(pyfuncitem.config)
             for fixname, fixtures in pyfuncitem._fixtureinfo.name2fixturedefs.items():
                 # name2fixturedefs is a dict between fixture name and a list of matching
@@ -698,7 +697,6 @@ def pytest_runtest_setup(item: pytest.Item) -> None:
     marker = item.get_closest_marker("asyncio")
     if marker is None or not is_async_test(item):
         return
-    item = cast(PytestAsyncioFunction, item)
     runner_fixture_id = f"_{item.loop_scope}_scoped_runner"
     fixturenames = item.fixturenames  # type: ignore[attr-defined]
     if runner_fixture_id not in fixturenames:
@@ -831,7 +829,7 @@ def event_loop_policy() -> AbstractEventLoopPolicy:
     return _get_event_loop_policy()
 
 
-def is_async_test(item: Item) -> bool:
+def is_async_test(item: Item) -> TypeIs[PytestAsyncioFunction]:
     """Returns whether a test item is a pytest-asyncio test"""
     return isinstance(item, PytestAsyncioFunction)