gh-84649: Fix unstable test_rollover_at_midnight (GH-154463)

Create the log file in a fresh directory under a name which has never
been used.  On Windows, NTFS file tunneling restored the original
creation time of a file recreated with the same name, which made the
rollover time earlier than the current time and caused an unwanted
rollover.

Also check that the rollover does not happen before the specified time.

Co-authored-by: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

Author: serhiy-storchaka

Lib/test/test_logging.py

@@ -6704,7 +6704,14 @@ def add_record(message: str) -> None:
         self.assertTrue(found, msg=msg)
 
     def test_rollover_at_midnight(self, weekly=False):
+        # Create the log file in a fresh directory under a never used name:
+        # on Windows, NTFS file tunneling restores the original creation time
+        # of a file recreated with the same name.
         os_helper.unlink(self.fn)
+        dirname = tempfile.mkdtemp()
+        self.addCleanup(os_helper.rmtree, dirname)
+        self.fn = os.path.join(dirname, 'test_rollover.log')
+
         # Emit the first records a little after the beginning of a whole
         # second, so that their file times fall inside that second and not the
         # previous one, which would cause an unwanted rollover.
@@ -6730,7 +6737,24 @@ def test_rollover_at_midnight(self, weekly=False):
         # changed, so the rollover cannot be forced by back-dating the file.
         # Wait until the clock reaches a rollover time set one second ahead.
         rollover = int(time.time()) + 1
+        if rollover - time.time() < 0.1:
+            # Leave time to emit a record before the rollover time.
+            rollover += 1
         atTime = datetime.datetime.fromtimestamp(rollover).time()
+        rolloverDate = (datetime.datetime.fromtimestamp(rollover)
+                        - datetime.timedelta(days=7 if weekly else 1))
+        otherfn = f'{self.fn}.{rolloverDate:%Y-%m-%d}'
+
+        # A record emitted before the rollover time is not rolled over.
+        fh = logging.handlers.TimedRotatingFileHandler(
+            self.fn, encoding="utf-8", when=when, atTime=atTime)
+        fh.setFormatter(fmt)
+        r2 = logging.makeLogRecord({'msg': 'testing1 3'})
+        fh.emit(r2)
+        fh.close()
+        self.assertFalse(os.path.exists(otherfn),
+                         msg=f'{otherfn} was rolled over too early')
+
         while time.time() < rollover:
             time.sleep(rollover - time.time())
         for i in range(2):
@@ -6740,9 +6764,6 @@ def test_rollover_at_midnight(self, weekly=False):
             r2 = logging.makeLogRecord({'msg': f'testing2 {i}'})
             fh.emit(r2)
             fh.close()
-        rolloverDate = (datetime.datetime.fromtimestamp(rollover)
-                        - datetime.timedelta(days=7 if weekly else 1))
-        otherfn = f'{self.fn}.{rolloverDate:%Y-%m-%d}'
         self.assertLogFile(otherfn)
         with open(self.fn, encoding="utf-8") as f:
             for i, line in enumerate(f):