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.
diff --git a/Lib/unittest/_log.py b/Lib/unittest/_log.py
new file mode 100644
index 0000000..94e7e75
--- /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 d0ee561..f8bc865 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 @@
-_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 @@
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):