Use the ProactorEventLoop on Windows.

tests/conftest.py

@@ -21,6 +21,12 @@ from .handlers.api.base import Query
 sys._called_from_test = True
 sys.original_platform = sys.platform
 
+if sys.platform.startswith("win"):
+    import asyncio
+    # use the Proactor event loop on Windows
+    loop = asyncio.ProactorEventLoop()
+    asyncio.set_event_loop(loop)
+
 
 @pytest.fixture(scope='function')
 async def http_client(aiohttp_client):

tests/handlers/test_index.py

@@ -70,7 +70,7 @@ async def test_web_ui(http_client, tmpdir):
             f.write('world')
         response = await http_client.get('/static/web-ui/testing.txt')
         assert response.status == 200
-    os.remove(get_static('web-ui/testing.txt'))
+        os.remove(tmpfile)
 
 
 async def test_web_ui_not_found(http_client, tmpdir):