from contextlib import contextmanager
import imp
import os.path
from test import support
import unittest
import sys
def case_insensitive_tests(class_):
"""Class decorator that nullifies tests requiring a case-insensitive
file system."""
# Windows is the only OS that is *always* case-insensitive
# (OS X *can* be case-sensitive).
if sys.platform not in ('win32', 'cygwin'):
changed_name = __file__.upper()
if changed_name == __file__:
changed_name = __file__.lower()
if os.path.exists(changed_name):
return class_
else:
return unittest.TestCase
else:
return class_
@contextmanager
def uncache(*names):
"""Uncache a module from sys.modules.
A basic sanity check is performed to prevent uncaching modules that either
cannot/shouldn't be uncached.
"""
for name in names:
if name in ('sys', 'marshal', 'imp'):
raise ValueError(
"cannot uncache {0} as it will break _importlib".format(name))
try:
del sys.modules[name]
except KeyError:
pass
try:
yield
finally:
for name in names:
try:
del sys.modules[name]
except KeyError:
pass
@contextmanager
def import_state(**kwargs):
"""Context manager to manage the various importers and stored state in the
sys module.
The 'modules' attribute is not supported as the interpreter state stores a
pointer to the dict that the interpreter uses internally;
reassigning to sys.modules does not have the desired effect.
"""
originals = {}
try:
for attr, default in (('meta_path', []), ('path', []),
('path_hooks', []),
('path_importer_cache', {})):
originals[attr] = getattr(sys, attr)
if attr in kwargs:
new_value = kwargs[attr]
del kwargs[attr]
else:
new_value = default
setattr(sys, attr, new_value)
if len(kwargs):
raise ValueError(
'unrecognized arguments: {0}'.format(kwargs.keys()))
yield
finally:
for attr, value in originals.items():
setattr(sys, attr, value)
class mock_modules:
"""A mock importer/loader."""
def __init__(self, *names):
self.modules = {}
for name in names:
if not name.endswith('.__init__'):
import_name = name
else:
import_name = name[:-len('.__init__')]
if '.' not in name:
package = None
elif import_name == name:
package = name.rsplit('.', 1)[0]
else:
package = import_name
module = imp.new_module(import_name)
module.__loader__ = self
module.__file__ = '<mock __file__>'
module.__package__ = package
module.attr = name
if import_name != name:
module.__path__ = ['<mock __path__>']
self.modules[import_name] = module
def __getitem__(self, name):
return self.modules[name]
def find_module(self, fullname, path=None):
if fullname not in self.modules:
return None
else:
return self
def load_module(self, fullname):
if fullname not in self.modules:
raise ImportError
else:
sys.modules[fullname] = self.modules[fullname]
return self.modules[fullname]
def __enter__(self):
self._uncache = uncache(*self.modules.keys())
self._uncache.__enter__()
return self
def __exit__(self, *exc_info):
self._uncache.__exit__(None, None, None)
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