Files
deb-python-gabbi/gabbi/fixture.py
2015-01-05 12:07:57 +00:00

89 lines
2.6 KiB
Python

# Copyright 2014, 2015 Red Hat
#
# Authors: Chris Dent <chdent@redhat.com>
#
# 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.
"""Manage fixtures for gabbi at the test suite level."""
import sys
from contextlib import contextmanager
import six
class GabbiFixtureError(Exception):
"""Generic exception for GabbiFixture."""
pass
class GabbiFixture(object):
"""A context manager that operates as a fixture.
Subclasses must implement start_fixture and stop_fixture, each of which
contain the logic for stopping and starting whatever the fixture is.
What a fixture is is left as an exercise for the implementor.
These context managers will be nested so any actually work needs to
happen in `start_fixture` and `stop_fixture` and not in ``__init__``.
Otherwise exception handling will not work properly.
"""
def __enter__(self):
self.start_fixture()
def __exit__(self, type, value, traceback):
self.stop_fixture()
def start_fixture(self):
"""Implement the actual workings of starting the fixture here."""
pass
def stop_fixture(self):
"""Implement the actual workings of stopping the fixture here."""
pass
@contextmanager
def nest(fixtures):
"""Nest a series of fixtures.
This is duplicated from ``nested`` in the stdlib, which has been
deprecated because of issues with how exceptions are difficult to
handle during ``__init__``. Gabbi needs to nest an unknown number
of fixtures dynamically, so the ``with`` syntax that replaces
``nested`` will not work.
"""
vars = []
exits = []
exc = (None, None, None)
try:
for fixture in fixtures:
enter = fixture.__enter__
exit = fixture.__exit__
vars.append(enter())
exits.append(exit)
yield vars
except:
exc = sys.exc_info()
finally:
while exits:
exit = exits.pop()
try:
if exit(*exc):
exc = (None, None, None)
except:
exc = sys.exc_info()
if exc != (None, None, None):
six.reraise(exc[0], exc[1], exc[2])