pythongh-102402: Fix logging test_relativeCreated_has_higher_precisio…

…n() leak (python#117985)

Fix a reference leak in test_relativeCreated_has_higher_precision()
of test_logging: don't reimport the logging the logging module.

Lib/test/test_logging.py

@@ -4598,27 +4598,25 @@ def test_msecs_has_no_floating_point_precision_loss(self):
  self.assertEqual(record.msecs, want)
  self.assertEqual(record.created, ns / 1e9)
 
+ # The test overrides a private attribute
+ @support.cpython_only
  def test_relativeCreated_has_higher_precision(self):
  # See issue gh-102402
  ns = 1_677_903_920_000_998_503 # approx. 2023-03-04 04:25:20 UTC
  offsets_ns = (200, 500, 12_354, 99_999, 1_677_903_456_999_123_456)
- orig_modules = import_helper._save_and_remove_modules(['logging'])
- try:
- with patch("time.time_ns") as patched_ns:
- # mock for module import
- patched_ns.return_value = ns
- import logging
- for offset_ns in offsets_ns:
- new_ns = ns + offset_ns
- # mock for log record creation
- patched_ns.return_value = new_ns
- record = logging.makeLogRecord({'msg': 'test'})
- self.assertAlmostEqual(record.created, new_ns / 1e9, places=6)
- # After PR gh-102412, precision (places) increases from 3 to 7
- self.assertAlmostEqual(record.relativeCreated, offset_ns / 1e6, places=7)
- finally:
- import_helper._save_and_remove_modules(['logging'])
- sys.modules.update(orig_modules)
+
+ with (patch("time.time_ns") as time_ns_mock,
+ support.swap_attr(logging, '_startTime', ns)):
+ for offset_ns in offsets_ns:
+ # mock for log record creation
+ new_ns = ns + offset_ns
+ time_ns_mock.return_value = new_ns
+
+ record = logging.makeLogRecord({'msg': 'test'})
+ self.assertAlmostEqual(record.created, new_ns / 1e9, places=6)
+
+ # After PR gh-102412, precision (places) increases from 3 to 7
+ self.assertAlmostEqual(record.relativeCreated, offset_ns / 1e6, places=7)
 
 
 class TestBufferingFormatter(logging.BufferingFormatter):