try to set asyncio policy

tests/units/conftest.py

@@ -1,5 +1,6 @@
 """Test fixtures."""
 
+import asyncio
 import contextlib
 import os
 import platform
@@ -24,6 +25,11 @@ from .states import (
 )
 
 
+def pytest_configure(config):
+    if config.getoption("asyncio_mode") == "auto":
+        asyncio.set_event_loop_policy(asyncio.DefaultEventLoopPolicy())
+
+
 @pytest.fixture
 def app() -> App:
     """A base app.