Give the test loop factory a fallback for fixture-only runners

pytest-asyncio only parametrizes the loop factory for async tests, so a
synchronous test pulling in an async fixture built that fixture's runner
with a stock loop, losing the executor and the loop.time binding that the
policy used to supply everywhere.

Overriding _asyncio_loop_factory keeps the parametrized value when there
is one and falls back to create_event_loop otherwise. The added tests
cover both the synchronous and the async path.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01PRmnu5HiXQUaHcHnNCvBSU

tests/conftest.py

@@ -38,6 +38,7 @@ import freezegun
 import multidict
 import pytest
 import pytest_asyncio
+from pytest_asyncio.plugin import LoopFactory
 import pytest_socket
 import requests_mock
 import respx
@@ -158,6 +159,17 @@ def pytest_asyncio_loop_factories() -> dict[str, Callable[[], AbstractEventLoop]
     return {"homeassistant": runner.create_event_loop}
 
 
+@pytest.fixture(scope="session", autouse=True)
+def _asyncio_loop_factory(request: pytest.FixtureRequest) -> LoopFactory:
+    """Cover the runners pytest_asyncio_loop_factories does not reach.
+
+    pytest-asyncio only parametrizes the factory for async tests, so a
+    synchronous test pulling in an async fixture would otherwise build that
+    fixture's runner with a stock loop.
+    """
+    return getattr(request, "param", None) or runner.create_event_loop
+
+
 # Capture the real socket functions before any test patches them
 _real_getaddrinfo = socket.getaddrinfo
 

tests/test_runner.py

@@ -434,3 +434,21 @@ def test_ensure_single_execution_sequential_runs(tmp_path: Path) -> None:
 
     # Lock file should still exist after second run (not unlinked)
     assert lock_file_path.exists()
+
+
+def _assert_hass_event_loop(loop: asyncio.AbstractEventLoop) -> None:
+    """Assert the loop carries the Home Assistant customizations."""
+    assert loop.time is runner.monotonic
+    assert isinstance(loop._default_executor, executor.InterruptibleThreadPoolExecutor)
+
+
+def test_sync_test_gets_hass_event_loop(hass: HomeAssistant) -> None:
+    """Test a synchronous test builds the async hass fixture on our loop."""
+    # pytest-asyncio only parametrizes the loop factory for async tests
+    _assert_hass_event_loop(hass.loop)
+
+
+async def test_async_test_gets_hass_event_loop(hass: HomeAssistant) -> None:
+    """Test an async test runs on our loop."""
+    _assert_hass_event_loop(asyncio.get_running_loop())
+    _assert_hass_event_loop(hass.loop)