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from importlib import Import
from contextlib import contextmanager
from functools import update_wrapper
import imp
import os.path
from test.support import unlink
import sys
from tempfile import gettempdir
using___import__ = False
def import_(*args, **kwargs):
"""Delegate to allow for injecting different implementations of import."""
if using___import__:
return __import__(*args, **kwargs)
return Import()(*args, **kwargs)
def importlib_only(fxn):
"""Decorator to mark which tests are not supported by the current
implementation of __import__()."""
def inner(*args, **kwargs):
if using___import__:
return
else:
return fxn(*args, **kwargs)
update_wrapper(inner, fxn)
return inner
def writes_bytecode(fxn):
"""Decorator that returns the function if writing bytecode is enabled, else
a stub function that accepts anything and simply returns None."""
if sys.dont_write_bytecode:
return lambda *args, **kwargs: None
else:
return fxn
def case_insensitive_tests(class_):
"""Class decorator that nullifies tests that require a case-insensitive
file system."""
if sys.platform not in ('win32', 'darwin', 'cygwin'):
return object()
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)
@contextmanager
def create_modules(*names):
"""Temporarily create each named module with an attribute (named 'attr')
that contains the name passed into the context manager that caused the
creation of the module.
All files are created in a temporary directory specified by
tempfile.gettempdir(). This directory is inserted at the beginning of
sys.path. When the context manager exits all created files (source and
bytecode) are explicitly deleted.
No magic is performed when creating packages! This means that if you create
a module within a package you must also create the package's __init__ as
well.
"""
source = 'attr = {0!r}'
created_paths = []
mapping = {}
try:
temp_dir = gettempdir()
mapping['.root'] = temp_dir
import_names = set()
for name in names:
if not name.endswith('__init__'):
import_name = name
else:
import_name = name[:-len('.__init__')]
import_names.add(import_name)
if import_name in sys.modules:
del sys.modules[import_name]
name_parts = name.split('.')
file_path = temp_dir
for directory in name_parts[:-1]:
file_path = os.path.join(file_path, directory)
if not os.path.exists(file_path):
os.mkdir(file_path)
created_paths.append(file_path)
file_path = os.path.join(file_path, name_parts[-1] + '.py')
with open(file_path, 'w') as file:
file.write(source.format(name))
created_paths.append(file_path)
mapping[name] = file_path
uncache_manager = uncache(*import_names)
uncache_manager.__enter__()
state_manager = import_state(path=[temp_dir])
state_manager.__enter__()
yield mapping
finally:
state_manager.__exit__(None, None, None)
uncache_manager.__exit__(None, None, None)
# Reverse the order for path removal to unroll directory creation.
for path in reversed(created_paths):
if file_path.endswith('.py'):
unlink(path)
unlink(path + 'c')
unlink(path + 'o')
else:
os.rmdir(path)
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)
def mock_path_hook(*entries, importer):
"""A mock sys.path_hooks entry."""
def hook(entry):
if entry not in entries:
raise ImportError
return importer
return hook
def bytecode_path(source_path):
for suffix, _, type_ in imp.get_suffixes():
if type_ == imp.PY_COMPILED:
bc_suffix = suffix
break
else:
raise ValueError("no bytecode suffix is defined")
return os.path.splitext(source_path)[0] + bc_suffix
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