synapse/tests/unittest.py

# -*- coding: utf-8 -*-
# Copyright 2014 OpenMarket Ltd
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#     http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.

from twisted.trial import unittest

import logging


# logging doesn't have a "don't log anything at all EVARRRR setting,
# but since the highest value is 50, 1000000 should do ;)
NEVER = 1000000

logging.getLogger().addHandler(logging.StreamHandler())
logging.getLogger().setLevel(NEVER)


def around(target):
    """A CLOS-style 'around' modifier, which wraps the original method of the
    given instance with another piece of code.

    @around(self)
    def method_name(orig, *args, **kwargs):
        return orig(*args, **kwargs)
    """
    def _around(code):
        name = code.__name__
        orig = getattr(target, name)
        def new(*args, **kwargs):
            return code(orig, *args, **kwargs)
        setattr(target, name, new)
    return _around


class TestCase(unittest.TestCase):
    """A subclass of twisted.trial's TestCase which looks for 'loglevel'
    attributes on both itself and its individual test methods, to override the
    root logger's logging level while that test (case|method) runs."""

    def __init__(self, methodName, *args, **kwargs):
        super(TestCase, self).__init__(methodName, *args, **kwargs)

        method = getattr(self, methodName)

        level = getattr(method, "loglevel",
                    getattr(self, "loglevel",
                        NEVER))

        @around(self)
        def setUp(orig):
            old_level = logging.getLogger().level

            if old_level != level:
                @around(self)
                def tearDown(orig):
                    ret = orig()
                    logging.getLogger().setLevel(old_level)
                    return ret

            logging.getLogger().setLevel(level)
            return orig()


def DEBUG(target):
    """A decorator to set the .loglevel attribute to logging.DEBUG.
    Can apply to either a TestCase or an individual test method."""
    target.loglevel = logging.DEBUG
    return target