test_timeout: Skip test_timeout_warn on Python 3.11 for coverage issue.

Signed-off-by: Anders Kaseorg <anders@zulip.com>

zerver/lib/timeout.py

@@ -84,9 +84,9 @@ def timeout(timeout: float, func: Callable[[], ResultT]) -> ResultT:
         # kill it), just raise from here; the thread _may still be
         # running_ because it failed to see any of our exceptions, and
         # we just ignore it.
-        if thread.is_alive():
+        if thread.is_alive():  # nocoverage
             logging.warning("Failed to time out backend thread")
-        raise TimeoutExpiredError
+        raise TimeoutExpiredError  # nocoverage
 
     if thread.exc_info[1] is not None:
         # Died with some other exception; re-raise it

zerver/tests/test_timeout.py

@@ -1,5 +1,7 @@
+import sys
 import time
 import traceback
+from unittest import skipIf
 
 from zerver.lib.test_classes import ZulipTestCase
 from zerver.lib.timeout import TimeoutExpiredError, timeout
@@ -39,6 +41,7 @@ class TimeoutTestCase(ZulipTestCase):
             self.assertIn("in something_exceptional", tb[-1])
             self.assertIn("raise ValueError", tb[-1])
 
+    @skipIf(sys.version_info >= (3, 11), "https://github.com/nedbat/coveragepy/issues/1626")
     def test_timeout_warn(self) -> None:
         # If the sleep is long enough, it will outlast the attempts to
         # kill it