tests: assert we are in a good state on autoreply

tests/test_websocket.py

@@ -28,6 +28,7 @@ import pytest
 import websockets
 from logbook import Logger
 from wsproto import WSConnection, ConnectionType
+from wsproto.connection import ConnectionState
 from wsproto.events import (
     Request,
     Message,
@@ -132,6 +133,7 @@ class AsyncWebsocket:
             break
 
         if isinstance(event, CloseConnection):
+            assert self.ws.state is ConnectionState.REMOTE_CLOSING
             await self.send(event.response())
             if process_event:
                 raise websockets.ConnectionClosed(