Fixed KeyboardInterrupt hanging the asyncio test runner (#779)

docs/versionhistory.rst

@@ -42,6 +42,7 @@ This library adheres to `Semantic Versioning 2.0 <http://semver.org/>`_.
   arrives in an exception group)
 - Fixed support for Linux abstract namespaces in UNIX sockets that was broken in v4.2
   (#781 <https://github.com/agronholm/anyio/issues/781>_; PR by @tapetersen)
+- Fixed ``KeyboardInterrupt`` (ctrl+c) hanging the asyncio pytest runner
 
 **4.4.0**
 

src/anyio/_backends/_asyncio.py

@@ -2082,13 +2082,23 @@ async def _run_tests_and_fixtures(
             tuple[Awaitable[T_Retval], asyncio.Future[T_Retval]]
         ],
     ) -> None:
+        from _pytest.outcomes import OutcomeException
+
         with receive_stream, self._send_stream:
             async for coro, future in receive_stream:
                 try:
                     retval = await coro
+                except CancelledError as exc:
+                    if not future.cancelled():
+                        future.cancel(*exc.args)
+
+                    raise
                 except BaseException as exc:
                     if not future.cancelled():
                         future.set_exception(exc)
+
+                    if not isinstance(exc, (Exception, OutcomeException)):
+                        raise
                 else:
                     if not future.cancelled():
                         future.set_result(retval)

tests/test_pytest_plugin.py

@@ -441,3 +441,30 @@ async def test_debugger_exit():
 
     result = testdir.runpytest(*pytest_args)
     result.assert_outcomes()
+
+
+@pytest.mark.parametrize("anyio_backend", get_all_backends(), indirect=True)
+def test_keyboardinterrupt_during_test(
+    testdir: Pytester, anyio_backend_name: str
+) -> None:
+    testdir.makepyfile(
+        f"""
+        import pytest
+        from anyio import create_task_group, sleep
+
+        @pytest.fixture
+        def anyio_backend():
+            return {anyio_backend_name!r}
+
+        async def send_keyboardinterrupt():
+            raise KeyboardInterrupt
+
+        @pytest.mark.anyio
+        async def test_anyio_mark_first():
+            async with create_task_group() as tg:
+                tg.start_soon(send_keyboardinterrupt)
+                await sleep(10)
+        """
+    )
+
+    testdir.runpytest_subprocess(*pytest_args, timeout=3)