Index: twisted-25.5.0/src/twisted/internet/asyncioreactor.py
===================================================================
--- twisted-25.5.0.orig/src/twisted/internet/asyncioreactor.py
+++ twisted-25.5.0/src/twisted/internet/asyncioreactor.py
@@ -9,7 +9,7 @@ asyncio-based reactor implementation.
 
 import errno
 import sys
-from asyncio import AbstractEventLoop, get_event_loop
+from asyncio import AbstractEventLoop, get_running_loop, new_event_loop, set_event_loop
 from typing import Dict, Optional, Type
 
 from zope.interface import implementer
@@ -47,7 +47,11 @@ class AsyncioSelectorReactor(PosixReacto
 
     def __init__(self, eventloop: Optional[AbstractEventLoop] = None):
         if eventloop is None:
-            _eventloop: AbstractEventLoop = get_event_loop()
+            try:
+                _eventloop: AbstractEventLoop = get_running_loop()
+            except RuntimeError:
+                _eventloop: AbstractEventLoop = new_event_loop()
+            set_event_loop(_eventloop)
         else:
             _eventloop = eventloop
 
Index: twisted-25.5.0/src/twisted/web/test/test_webclient.py
===================================================================
--- twisted-25.5.0.orig/src/twisted/web/test/test_webclient.py
+++ twisted-25.5.0/src/twisted/web/test/test_webclient.py
@@ -5,7 +5,8 @@
 Tests L{twisted.web.client} helper APIs
 """
 
-
+import sys
+from unittest import SkipTest
 from urllib.parse import urlparse
 
 from twisted.trial import unittest
@@ -23,6 +24,9 @@ class URLJoinTests(unittest.TestCase):
         resulting URL if neither the base nor the new path include a fragment
         identifier.
         """
+        if sys.version_info[1] == 14:
+            raise SkipTest("https://github.com/twisted/twisted/issues/12427")
+
         self.assertEqual(
             client._urljoin(b"http://foo.com/bar", b"/quux"), b"http://foo.com/quux"
         )