Ensure shutdown of async exchange, fix test

freqtrade/exchange/exchange_ws.py

@@ -55,8 +55,12 @@ class ExchangeWS:
         logger.debug("Stopped")
 
     async def _cleanup_async(self) -> None:
-        await self.ccxt_object.close()
+        try:
-        self.__cleanup_called = True
+            await self.ccxt_object.close()
+        except Exception:
+            logger.exception("Exception in _cleanup_async")
+        finally:
+            self.__cleanup_called = True
 
     def cleanup_expired(self) -> None:
         """

tests/exchange/test_exchange_ws.py

@@ -46,6 +46,7 @@ async def test_exchangews_ohlcv(mocker):
     config = MagicMock()
     ccxt_object = MagicMock()
     ccxt_object.watch_ohlcv = AsyncMock()
+    ccxt_object.close = AsyncMock()
     mocker.patch("freqtrade.exchange.exchange_ws.ExchangeWS._start_forever", MagicMock())
 
     exchange_ws = ExchangeWS(config, ccxt_object)