Optional argument to QEventLoop constructor for already running loops

asyncqt/__init__.py

@@ -255,7 +255,7 @@ class _QEventLoop:
     ...     loop.run_until_complete(xplusy(2, 2))
     """
 
-    def __init__(self, app=None, set_running_loop=True):
+    def __init__(self, app=None, set_running_loop=True, already_running=False):
         self.__app = app or QApplication.instance()
         assert self.__app is not None, 'No QApplication has been instantiated'
         self.__is_running = False
@@ -276,6 +276,11 @@ def __init__(self, app=None, set_running_loop=True):
         if set_running_loop:
             asyncio.events._set_running_loop(self)
 
+        # We have to set __is_running to True after calling
+        # super().__init__() because of a bug in BaseEventLoop.
+        if already_running:
+            self.__is_running = True
+
     def run_forever(self):
         """Run eventloop forever."""
         self.__is_running = True