[Python-checkins] bpo-40275: Avoid importing logging in test.support (GH-19601)
Serhiy Storchaka
webhook-mailer at python.org
Sat Apr 25 04:35:27 EDT 2020
https://github.com/python/cpython/commit/515fce4fc4bb0d2db97b17df275cf90640017f56
commit: 515fce4fc4bb0d2db97b17df275cf90640017f56
branch: master
author: Serhiy Storchaka <storchaka at gmail.com>
committer: GitHub <noreply at github.com>
date: 2020-04-25T11:35:18+03:00
summary:
bpo-40275: Avoid importing logging in test.support (GH-19601)
Import logging lazily in assertLogs() in unittest.
Move TestHandler from test.support to logging_helper.
files:
A Lib/test/support/logging_helper.py
A Lib/unittest/_log.py
A Misc/NEWS.d/next/Library/2020-04-20-19-06-55.bpo-40275.9UcN2g.rst
M Doc/library/test.rst
M Lib/test/support/__init__.py
M Lib/test/test_logging.py
M Lib/unittest/case.py
diff --git a/Doc/library/test.rst b/Doc/library/test.rst
index 1e6b1116212ef..c2aaecc183e77 100644
--- a/Doc/library/test.rst
+++ b/Doc/library/test.rst
@@ -1410,11 +1410,6 @@ The :mod:`test.support` module defines the following classes:
Run *test* and return the result.
-.. class:: TestHandler(logging.handlers.BufferingHandler)
-
- Class for logging support.
-
-
.. class:: FakePath(path)
Simple :term:`path-like object`. It implements the :meth:`__fspath__`
diff --git a/Lib/test/support/__init__.py b/Lib/test/support/__init__.py
index 15cf45da18e2c..f48decc704cb8 100644
--- a/Lib/test/support/__init__.py
+++ b/Lib/test/support/__init__.py
@@ -15,7 +15,6 @@
import importlib
import importlib.util
import locale
-import logging.handlers
import os
import platform
import re
@@ -99,8 +98,6 @@
"open_urlresource",
# processes
'temp_umask', "reap_children",
- # logging
- "TestHandler",
# threads
"threading_setup", "threading_cleanup", "reap_threads", "start_threads",
# miscellaneous
@@ -2368,37 +2365,6 @@ def optim_args_from_interpreter_flags():
optimization settings in sys.flags."""
return subprocess._optim_args_from_interpreter_flags()
-#============================================================
-# Support for assertions about logging.
-#============================================================
-
-class TestHandler(logging.handlers.BufferingHandler):
- def __init__(self, matcher):
- # BufferingHandler takes a "capacity" argument
- # so as to know when to flush. As we're overriding
- # shouldFlush anyway, we can set a capacity of zero.
- # You can call flush() manually to clear out the
- # buffer.
- logging.handlers.BufferingHandler.__init__(self, 0)
- self.matcher = matcher
-
- def shouldFlush(self):
- return False
-
- def emit(self, record):
- self.format(record)
- self.buffer.append(record.__dict__)
-
- def matches(self, **kwargs):
- """
- Look for a saved dict whose keys/values match the supplied arguments.
- """
- result = False
- for d in self.buffer:
- if self.matcher.matches(d, **kwargs):
- result = True
- break
- return result
class Matcher(object):
diff --git a/Lib/test/support/logging_helper.py b/Lib/test/support/logging_helper.py
new file mode 100644
index 0000000000000..12fcca4f0f08d
--- /dev/null
+++ b/Lib/test/support/logging_helper.py
@@ -0,0 +1,29 @@
+import logging.handlers
+
+class TestHandler(logging.handlers.BufferingHandler):
+ def __init__(self, matcher):
+ # BufferingHandler takes a "capacity" argument
+ # so as to know when to flush. As we're overriding
+ # shouldFlush anyway, we can set a capacity of zero.
+ # You can call flush() manually to clear out the
+ # buffer.
+ logging.handlers.BufferingHandler.__init__(self, 0)
+ self.matcher = matcher
+
+ def shouldFlush(self):
+ return False
+
+ def emit(self, record):
+ self.format(record)
+ self.buffer.append(record.__dict__)
+
+ def matches(self, **kwargs):
+ """
+ Look for a saved dict whose keys/values match the supplied arguments.
+ """
+ result = False
+ for d in self.buffer:
+ if self.matcher.matches(d, **kwargs):
+ result = True
+ break
+ return result
diff --git a/Lib/test/test_logging.py b/Lib/test/test_logging.py
index 241ed2c91de13..e1d0eb8145fe2 100644
--- a/Lib/test/test_logging.py
+++ b/Lib/test/test_logging.py
@@ -44,6 +44,7 @@
from test.support.script_helper import assert_python_ok, assert_python_failure
from test import support
from test.support import socket_helper
+from test.support.logging_helper import TestHandler
import textwrap
import threading
import time
@@ -3524,7 +3525,7 @@ def test_formatting(self):
@unittest.skipUnless(hasattr(logging.handlers, 'QueueListener'),
'logging.handlers.QueueListener required for this test')
def test_queue_listener(self):
- handler = support.TestHandler(support.Matcher())
+ handler = TestHandler(support.Matcher())
listener = logging.handlers.QueueListener(self.queue, handler)
listener.start()
try:
@@ -3540,7 +3541,7 @@ def test_queue_listener(self):
# Now test with respect_handler_level set
- handler = support.TestHandler(support.Matcher())
+ handler = TestHandler(support.Matcher())
handler.setLevel(logging.CRITICAL)
listener = logging.handlers.QueueListener(self.queue, handler,
respect_handler_level=True)
diff --git a/Lib/unittest/_log.py b/Lib/unittest/_log.py
new file mode 100644
index 0000000000000..94e7e758bd9a0
--- /dev/null
+++ b/Lib/unittest/_log.py
@@ -0,0 +1,69 @@
+import logging
+import collections
+
+from .case import _BaseTestCaseContext
+
+
+_LoggingWatcher = collections.namedtuple("_LoggingWatcher",
+ ["records", "output"])
+
+class _CapturingHandler(logging.Handler):
+ """
+ A logging handler capturing all (raw and formatted) logging output.
+ """
+
+ def __init__(self):
+ logging.Handler.__init__(self)
+ self.watcher = _LoggingWatcher([], [])
+
+ def flush(self):
+ pass
+
+ def emit(self, record):
+ self.watcher.records.append(record)
+ msg = self.format(record)
+ self.watcher.output.append(msg)
+
+
+class _AssertLogsContext(_BaseTestCaseContext):
+ """A context manager used to implement TestCase.assertLogs()."""
+
+ LOGGING_FORMAT = "%(levelname)s:%(name)s:%(message)s"
+
+ def __init__(self, test_case, logger_name, level):
+ _BaseTestCaseContext.__init__(self, test_case)
+ self.logger_name = logger_name
+ if level:
+ self.level = logging._nameToLevel.get(level, level)
+ else:
+ self.level = logging.INFO
+ self.msg = None
+
+ def __enter__(self):
+ if isinstance(self.logger_name, logging.Logger):
+ logger = self.logger = self.logger_name
+ else:
+ logger = self.logger = logging.getLogger(self.logger_name)
+ formatter = logging.Formatter(self.LOGGING_FORMAT)
+ handler = _CapturingHandler()
+ handler.setFormatter(formatter)
+ self.watcher = handler.watcher
+ self.old_handlers = logger.handlers[:]
+ self.old_level = logger.level
+ self.old_propagate = logger.propagate
+ logger.handlers = [handler]
+ logger.setLevel(self.level)
+ logger.propagate = False
+ return handler.watcher
+
+ def __exit__(self, exc_type, exc_value, tb):
+ self.logger.handlers = self.old_handlers
+ self.logger.propagate = self.old_propagate
+ self.logger.setLevel(self.old_level)
+ if exc_type is not None:
+ # let unexpected exceptions pass through
+ return False
+ if len(self.watcher.records) == 0:
+ self._raiseFailure(
+ "no logs of level {} or higher triggered on {}"
+ .format(logging.getLevelName(self.level), self.logger.name))
diff --git a/Lib/unittest/case.py b/Lib/unittest/case.py
index d0ee561a3ae93..f8bc865ee8203 100644
--- a/Lib/unittest/case.py
+++ b/Lib/unittest/case.py
@@ -3,7 +3,6 @@
import sys
import functools
import difflib
-import logging
import pprint
import re
import warnings
@@ -297,73 +296,6 @@ def __exit__(self, exc_type, exc_value, tb):
-_LoggingWatcher = collections.namedtuple("_LoggingWatcher",
- ["records", "output"])
-
-
-class _CapturingHandler(logging.Handler):
- """
- A logging handler capturing all (raw and formatted) logging output.
- """
-
- def __init__(self):
- logging.Handler.__init__(self)
- self.watcher = _LoggingWatcher([], [])
-
- def flush(self):
- pass
-
- def emit(self, record):
- self.watcher.records.append(record)
- msg = self.format(record)
- self.watcher.output.append(msg)
-
-
-
-class _AssertLogsContext(_BaseTestCaseContext):
- """A context manager used to implement TestCase.assertLogs()."""
-
- LOGGING_FORMAT = "%(levelname)s:%(name)s:%(message)s"
-
- def __init__(self, test_case, logger_name, level):
- _BaseTestCaseContext.__init__(self, test_case)
- self.logger_name = logger_name
- if level:
- self.level = logging._nameToLevel.get(level, level)
- else:
- self.level = logging.INFO
- self.msg = None
-
- def __enter__(self):
- if isinstance(self.logger_name, logging.Logger):
- logger = self.logger = self.logger_name
- else:
- logger = self.logger = logging.getLogger(self.logger_name)
- formatter = logging.Formatter(self.LOGGING_FORMAT)
- handler = _CapturingHandler()
- handler.setFormatter(formatter)
- self.watcher = handler.watcher
- self.old_handlers = logger.handlers[:]
- self.old_level = logger.level
- self.old_propagate = logger.propagate
- logger.handlers = [handler]
- logger.setLevel(self.level)
- logger.propagate = False
- return handler.watcher
-
- def __exit__(self, exc_type, exc_value, tb):
- self.logger.handlers = self.old_handlers
- self.logger.propagate = self.old_propagate
- self.logger.setLevel(self.old_level)
- if exc_type is not None:
- # let unexpected exceptions pass through
- return False
- if len(self.watcher.records) == 0:
- self._raiseFailure(
- "no logs of level {} or higher triggered on {}"
- .format(logging.getLevelName(self.level), self.logger.name))
-
-
class _OrderedChainMap(collections.ChainMap):
def __iter__(self):
seen = set()
@@ -854,6 +786,8 @@ def assertLogs(self, logger=None, level=None):
self.assertEqual(cm.output, ['INFO:foo:first message',
'ERROR:foo.bar:second message'])
"""
+ # Lazy import to avoid importing logging if it is not needed.
+ from ._log import _AssertLogsContext
return _AssertLogsContext(self, logger, level)
def _getAssertEqualityFunc(self, first, second):
diff --git a/Misc/NEWS.d/next/Library/2020-04-20-19-06-55.bpo-40275.9UcN2g.rst b/Misc/NEWS.d/next/Library/2020-04-20-19-06-55.bpo-40275.9UcN2g.rst
new file mode 100644
index 0000000000000..09e0a97f3ed98
--- /dev/null
+++ b/Misc/NEWS.d/next/Library/2020-04-20-19-06-55.bpo-40275.9UcN2g.rst
@@ -0,0 +1,2 @@
+The :mod:`logging` package is now imported lazily in :mod:`unittest` only
+when the :meth:`~unittest.TestCase.assertLogs` assertion is used.
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