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# Copyright (C) 2009, 2010 Canonical Ltd
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 2 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, write to the Free Software
# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
import re
from ..cleanup import (
ExitStack,
)
from ..sixish import PY3
from .. import (
tests,
)
from contextlib import contextmanager
check_exception_chaining = PY3
# Imported from contextlib2's test_contextlib2.py
# Copyright: Copyright (c) 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008,
# 2009, 2010, 2011 Python Software Foundation
#
# PYTHON SOFTWARE FOUNDATION LICENSE VERSION 2
# --------------------------------------------
# .
# 1. This LICENSE AGREEMENT is between the Python Software Foundation
# ("PSF"), and the Individual or Organization ("Licensee") accessing and
# otherwise using this software ("Python") in source or binary form and
# its associated documentation.
# .
# 2. Subject to the terms and conditions of this License Agreement, PSF hereby
# grants Licensee a nonexclusive, royalty-free, world-wide license to reproduce,
# analyze, test, perform and/or display publicly, prepare derivative works,
# distribute, and otherwise use Python alone or in any derivative version,
# provided, however, that PSF's License Agreement and PSF's notice of copyright,
# i.e., "Copyright (c) 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010,
# 2011 Python Software Foundation; All Rights Reserved" are retained in Python
# alone or in any derivative version prepared by Licensee.
# .
# 3. In the event Licensee prepares a derivative work that is based on
# or incorporates Python or any part thereof, and wants to make
# the derivative work available to others as provided herein, then
# Licensee hereby agrees to include in any such work a brief summary of
# the changes made to Python.
# .
# 4. PSF is making Python available to Licensee on an "AS IS"
# basis. PSF MAKES NO REPRESENTATIONS OR WARRANTIES, EXPRESS OR
# IMPLIED. BY WAY OF EXAMPLE, BUT NOT LIMITATION, PSF MAKES NO AND
# DISCLAIMS ANY REPRESENTATION OR WARRANTY OF MERCHANTABILITY OR FITNESS
# FOR ANY PARTICULAR PURPOSE OR THAT THE USE OF PYTHON WILL NOT
# INFRINGE ANY THIRD PARTY RIGHTS.
# .
# 5. PSF SHALL NOT BE LIABLE TO LICENSEE OR ANY OTHER USERS OF PYTHON
# FOR ANY INCIDENTAL, SPECIAL, OR CONSEQUENTIAL DAMAGES OR LOSS AS
# A RESULT OF MODIFYING, DISTRIBUTING, OR OTHERWISE USING PYTHON,
# OR ANY DERIVATIVE THEREOF, EVEN IF ADVISED OF THE POSSIBILITY THEREOF.
# .
# 6. This License Agreement will automatically terminate upon a material
# breach of its terms and conditions.
# .
# 7. Nothing in this License Agreement shall be deemed to create any
# relationship of agency, partnership, or joint venture between PSF and
# Licensee. This License Agreement does not grant permission to use PSF
# trademarks or trade name in a trademark sense to endorse or promote
# products or services of Licensee, or any third party.
# .
# 8. By copying, installing or otherwise using Python, Licensee
# agrees to be bound by the terms and conditions of this License
# Agreement.
class TestExitStack(tests.TestCase):
def test_no_resources(self):
with ExitStack():
pass
def test_callback(self):
expected = [
((), {}),
((1,), {}),
((1, 2), {}),
((), dict(example=1)),
((1,), dict(example=1)),
((1, 2), dict(example=1)),
]
result = []
def _exit(*args, **kwds):
"""Test metadata propagation"""
result.append((args, kwds))
with ExitStack() as stack:
for args, kwds in reversed(expected):
if args and kwds:
f = stack.callback(_exit, *args, **kwds)
elif args:
f = stack.callback(_exit, *args)
elif kwds:
f = stack.callback(_exit, **kwds)
else:
f = stack.callback(_exit)
self.assertIs(f, _exit)
self.assertEqual(result, expected)
def test_push(self):
exc_raised = ZeroDivisionError
def _expect_exc(exc_type, exc, exc_tb):
self.assertIs(exc_type, exc_raised)
def _suppress_exc(*exc_details):
return True
def _expect_ok(exc_type, exc, exc_tb):
self.assertIsNone(exc_type)
self.assertIsNone(exc)
self.assertIsNone(exc_tb)
class ExitCM(object):
def __init__(self, check_exc):
self.check_exc = check_exc
def __enter__(self):
self.fail("Should not be called!")
def __exit__(self, *exc_details):
self.check_exc(*exc_details)
with ExitStack() as stack:
stack.push(_expect_ok)
cm = ExitCM(_expect_ok)
stack.push(cm)
stack.push(_suppress_exc)
cm = ExitCM(_expect_exc)
stack.push(cm)
stack.push(_expect_exc)
stack.push(_expect_exc)
1 / 0
def test_enter_context(self):
class TestCM(object):
def __enter__(self):
result.append(1)
def __exit__(self, *exc_details):
result.append(3)
result = []
cm = TestCM()
with ExitStack() as stack:
@stack.callback # Registered first => cleaned up last
def _exit():
result.append(4)
self.assertIsNotNone(_exit)
stack.enter_context(cm)
result.append(2)
self.assertEqual(result, [1, 2, 3, 4])
def test_close(self):
result = []
with ExitStack() as stack:
@stack.callback
def _exit():
result.append(1)
self.assertIsNotNone(_exit)
stack.close()
result.append(2)
self.assertEqual(result, [1, 2])
def test_pop_all(self):
result = []
with ExitStack() as stack:
@stack.callback
def _exit():
result.append(3)
self.assertIsNotNone(_exit)
new_stack = stack.pop_all()
result.append(1)
result.append(2)
new_stack.close()
self.assertEqual(result, [1, 2, 3])
def test_exit_raise(self):
def _raise():
with ExitStack() as stack:
stack.push(lambda *exc: False)
1 / 0
self.assertRaises(ZeroDivisionError, _raise)
def test_exit_suppress(self):
with ExitStack() as stack:
stack.push(lambda *exc: True)
1 / 0
def test_exit_exception_chaining_reference(self):
# Sanity check to make sure that ExitStack chaining matches
# actual nested with statements
class RaiseExc:
def __init__(self, exc):
self.exc = exc
def __enter__(self):
return self
def __exit__(self, *exc_details):
raise self.exc
class RaiseExcWithContext:
def __init__(self, outer, inner):
self.outer = outer
self.inner = inner
def __enter__(self):
return self
def __exit__(self, *exc_details):
try:
raise self.inner
except:
raise self.outer
class SuppressExc:
def __enter__(self):
return self
def __exit__(self, *exc_details):
self.__class__.saved_details = exc_details
return True
try:
with RaiseExc(IndexError):
with RaiseExcWithContext(KeyError, AttributeError):
with SuppressExc():
with RaiseExc(ValueError):
1 / 0
except IndexError as exc:
if check_exception_chaining:
self.assertIsInstance(exc.__context__, KeyError)
self.assertIsInstance(exc.__context__.__context__, AttributeError)
# Inner exceptions were suppressed
self.assertIsNone(exc.__context__.__context__.__context__)
else:
self.fail("Expected IndexError, but no exception was raised")
# Check the inner exceptions
inner_exc = SuppressExc.saved_details[1]
self.assertIsInstance(inner_exc, ValueError)
if check_exception_chaining:
self.assertIsInstance(inner_exc.__context__, ZeroDivisionError)
def test_exit_exception_chaining(self):
# Ensure exception chaining matches the reference behaviour
def raise_exc(exc):
raise exc
saved_details = [None]
def suppress_exc(*exc_details):
saved_details[0] = exc_details
return True
try:
with ExitStack() as stack:
stack.callback(raise_exc, IndexError)
stack.callback(raise_exc, KeyError)
stack.callback(raise_exc, AttributeError)
stack.push(suppress_exc)
stack.callback(raise_exc, ValueError)
1 / 0
except IndexError as exc:
if check_exception_chaining:
self.assertIsInstance(exc.__context__, KeyError)
self.assertIsInstance(exc.__context__.__context__, AttributeError)
# Inner exceptions were suppressed
self.assertIsNone(exc.__context__.__context__.__context__)
else:
self.fail("Expected IndexError, but no exception was raised")
# Check the inner exceptions
inner_exc = saved_details[0][1]
self.assertIsInstance(inner_exc, ValueError)
if check_exception_chaining:
self.assertIsInstance(inner_exc.__context__, ZeroDivisionError)
def test_exit_exception_non_suppressing(self):
# http://bugs.python.org/issue19092
def raise_exc(exc):
raise exc
def suppress_exc(*exc_details):
return True
try:
with ExitStack() as stack:
stack.callback(lambda: None)
stack.callback(raise_exc, IndexError)
except Exception as exc:
self.assertIsInstance(exc, IndexError)
else:
self.fail("Expected IndexError, but no exception was raised")
try:
with ExitStack() as stack:
stack.callback(raise_exc, KeyError)
stack.push(suppress_exc)
stack.callback(raise_exc, IndexError)
except Exception as exc:
self.assertIsInstance(exc, KeyError)
else:
self.fail("Expected KeyError, but no exception was raised")
def test_exit_exception_with_correct_context(self):
# http://bugs.python.org/issue20317
@contextmanager
def gets_the_context_right(exc):
try:
yield
finally:
raise exc
exc1 = Exception(1)
exc2 = Exception(2)
exc3 = Exception(3)
exc4 = Exception(4)
# The contextmanager already fixes the context, so prior to the
# fix, ExitStack would try to fix it *again* and get into an
# infinite self-referential loop
try:
with ExitStack() as stack:
stack.enter_context(gets_the_context_right(exc4))
stack.enter_context(gets_the_context_right(exc3))
stack.enter_context(gets_the_context_right(exc2))
raise exc1
except Exception as exc:
self.assertIs(exc, exc4)
if check_exception_chaining:
self.assertIs(exc.__context__, exc3)
self.assertIs(exc.__context__.__context__, exc2)
self.assertIs(exc.__context__.__context__.__context__, exc1)
self.assertIsNone(
exc.__context__.__context__.__context__.__context__)
def test_exit_exception_with_existing_context(self):
# Addresses a lack of test coverage discovered after checking in a
# fix for issue 20317 that still contained debugging code.
def raise_nested(inner_exc, outer_exc):
try:
raise inner_exc
finally:
raise outer_exc
exc1 = Exception(1)
exc2 = Exception(2)
exc3 = Exception(3)
exc4 = Exception(4)
exc5 = Exception(5)
try:
with ExitStack() as stack:
stack.callback(raise_nested, exc4, exc5)
stack.callback(raise_nested, exc2, exc3)
raise exc1
except Exception as exc:
self.assertIs(exc, exc5)
if check_exception_chaining:
self.assertIs(exc.__context__, exc4)
self.assertIs(exc.__context__.__context__, exc3)
self.assertIs(exc.__context__.__context__.__context__, exc2)
self.assertIs(
exc.__context__.__context__.__context__.__context__, exc1)
self.assertIsNone(
exc.__context__.__context__.__context__.__context__.__context__)
def test_body_exception_suppress(self):
def suppress_exc(*exc_details):
return True
try:
with ExitStack() as stack:
stack.push(suppress_exc)
1 / 0
except IndexError as exc:
self.fail("Expected no exception, got IndexError")
def test_exit_exception_chaining_suppress(self):
with ExitStack() as stack:
stack.push(lambda *exc: True)
stack.push(lambda *exc: 1 / 0)
stack.push(lambda *exc: {}[1])
def test_excessive_nesting(self):
# The original implementation would die with RecursionError here
with ExitStack() as stack:
for i in range(10000):
stack.callback(int)
def test_instance_bypass(self):
class Example(object):
pass
cm = Example()
cm.__exit__ = object()
stack = ExitStack()
self.assertRaises(AttributeError, stack.enter_context, cm)
stack.push(cm)
# self.assertIs(stack._exit_callbacks[-1], cm)
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