test_logging.py 文件源码

def test_last_resort(self):
        # Test the last resort handler
        root = self.root_logger
        root.removeHandler(self.root_hdlr)
        old_stderr = sys.stderr
        old_lastresort = logging.lastResort
        old_raise_exceptions = logging.raiseExceptions
        try:
            sys.stderr = sio = io.StringIO()
            root.debug('This should not appear')
            self.assertEqual(sio.getvalue(), '')
            root.warning('This is your final chance!')
            self.assertEqual(sio.getvalue(), 'This is your final chance!\n')
            #No handlers and no last resort, so 'No handlers' message
            logging.lastResort = None
            sys.stderr = sio = io.StringIO()
            root.warning('This is your final chance!')
            self.assertEqual(sio.getvalue(), 'No handlers could be found for logger "root"\n')
            # 'No handlers' message only printed once
            sys.stderr = sio = io.StringIO()
            root.warning('This is your final chance!')
            self.assertEqual(sio.getvalue(), '')
            root.manager.emittedNoHandlerWarning = False
            #If raiseExceptions is False, no message is printed
            logging.raiseExceptions = False
            sys.stderr = sio = io.StringIO()
            root.warning('This is your final chance!')
            self.assertEqual(sio.getvalue(), '')
        finally:
            sys.stderr = old_stderr
            root.addHandler(self.root_hdlr)
            logging.lastResort = old_lastresort
            logging.raiseExceptions = old_raise_exceptions