Issue #28368: Refuse monitoring processes if the child watcher has no loop attached.

Patch by Vincent Michel.

1 files changed, 13 insertions, 1 deletions

diff --git a/Lib/test/test_asyncio/test_unix_events.py b/Lib/test/test_asyncio/test_unix_events.py
index 570022f..088ef40 100644
--- a/Lib/test/test_asyncio/test_unix_events.py
+++ b/Lib/test/test_asyncio/test_unix_events.py
@@ -11,6 +11,7 @@ import sys
 import tempfile
 import threading
 import unittest
+import warnings
 from unittest import mock
 
 if sys.platform == 'win32':
@@ -1391,7 +1392,9 @@ class ChildWatcherTestsMixin:
         with mock.patch.object(
                 old_loop, "remove_signal_handler") as m_remove_signal_handler:
 
-            self.watcher.attach_loop(None)
+            with self.assertWarnsRegex(
+                    RuntimeWarning, 'A loop is being detached'):
+                self.watcher.attach_loop(None)
 
             m_remove_signal_handler.assert_called_once_with(
                 signal.SIGCHLD)
@@ -1463,6 +1466,15 @@ class ChildWatcherTestsMixin:
                 if isinstance(self.watcher, asyncio.FastChildWatcher):
                     self.assertFalse(self.watcher._zombies)
 
+    @waitpid_mocks
+    def test_add_child_handler_with_no_loop_attached(self, m):
+        callback = mock.Mock()
+        with self.create_watcher() as watcher:
+            with self.assertRaisesRegex(
+                    RuntimeError,
+                    'the child watcher does not have a loop attached'):
+                watcher.add_child_handler(100, callback)
+
 
 class SafeChildWatcherTests (ChildWatcherTestsMixin, test_utils.TestCase):
     def create_watcher(self):