cpython/Lib/test/test_importlib/util.py

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import builtins
import contextlib
import errno
import functools
import importlib
from importlib import machinery, util, invalidate_caches
import os
import os.path
from test import support
import unittest
import sys
import tempfile
import types
BUILTINS = types.SimpleNamespace()
BUILTINS.good_name = None
BUILTINS.bad_name = None
if 'errno' in sys.builtin_module_names:
BUILTINS.good_name = 'errno'
if 'importlib' not in sys.builtin_module_names:
BUILTINS.bad_name = 'importlib'
EXTENSIONS = types.SimpleNamespace()
EXTENSIONS.path = None
EXTENSIONS.ext = None
EXTENSIONS.filename = None
EXTENSIONS.file_path = None
EXTENSIONS.name = '_testcapi'
def _extension_details():
global EXTENSIONS
for path in sys.path:
for ext in machinery.EXTENSION_SUFFIXES:
filename = EXTENSIONS.name + ext
file_path = os.path.join(path, filename)
if os.path.exists(file_path):
EXTENSIONS.path = path
EXTENSIONS.ext = ext
EXTENSIONS.filename = filename
EXTENSIONS.file_path = file_path
return
_extension_details()
def import_importlib(module_name):
"""Import a module from importlib both w/ and w/o _frozen_importlib."""
fresh = ('importlib',) if '.' in module_name else ()
frozen = support.import_fresh_module(module_name)
source = support.import_fresh_module(module_name, fresh=fresh,
blocked=('_frozen_importlib', '_frozen_importlib_external'))
return {'Frozen': frozen, 'Source': source}
def specialize_class(cls, kind, base=None, **kwargs):
# XXX Support passing in submodule names--load (and cache) them?
# That would clean up the test modules a bit more.
if base is None:
base = unittest.TestCase
elif not isinstance(base, type):
base = base[kind]
name = '{}_{}'.format(kind, cls.__name__)
bases = (cls, base)
specialized = types.new_class(name, bases)
specialized.__module__ = cls.__module__
specialized._NAME = cls.__name__
specialized._KIND = kind
for attr, values in kwargs.items():
value = values[kind]
setattr(specialized, attr, value)
return specialized
def split_frozen(cls, base=None, **kwargs):
frozen = specialize_class(cls, 'Frozen', base, **kwargs)
source = specialize_class(cls, 'Source', base, **kwargs)
return frozen, source
def test_both(test_class, base=None, **kwargs):
return split_frozen(test_class, base, **kwargs)
CASE_INSENSITIVE_FS = True
# 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 not os.path.exists(changed_name):
CASE_INSENSITIVE_FS = False
source_importlib = import_importlib('importlib')['Source']
__import__ = {'Frozen': staticmethod(builtins.__import__),
'Source': staticmethod(source_importlib.__import__)}
def case_insensitive_tests(test):
"""Class decorator that nullifies tests requiring a case-insensitive
file system."""
return unittest.skipIf(not CASE_INSENSITIVE_FS,
"requires a case-insensitive filesystem")(test)
def submodule(parent, name, pkg_dir, content=''):
path = os.path.join(pkg_dir, name + '.py')
with open(path, 'w') as subfile:
subfile.write(content)
return '{}.{}'.format(parent, name), path
@contextlib.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}".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
@contextlib.contextmanager
def temp_module(name, content='', *, pkg=False):
conflicts = [n for n in sys.modules if n.partition('.')[0] == name]
with support.temp_cwd(None) as cwd:
with uncache(name, *conflicts):
with support.DirsOnSysPath(cwd):
invalidate_caches()
location = os.path.join(cwd, name)
if pkg:
modpath = os.path.join(location, '__init__.py')
os.mkdir(name)
else:
modpath = location + '.py'
if content is None:
# Make sure the module file gets created.
content = ''
if content is not None:
# not a namespace package
with open(modpath, 'w') as modfile:
modfile.write(content)
yield location
@contextlib.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 _ImporterMock:
"""Base class to help with creating importer mocks."""
def __init__(self, *names, module_code={}):
self.modules = {}
self.module_code = {}
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 = types.ModuleType(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
if import_name in module_code:
self.module_code[import_name] = module_code[import_name]
def __getitem__(self, name):
return self.modules[name]
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)
class mock_modules(_ImporterMock):
"""Importer mock using PEP 302 APIs."""
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]
if fullname in self.module_code:
try:
self.module_code[fullname]()
except Exception:
del sys.modules[fullname]
raise
return self.modules[fullname]
class mock_spec(_ImporterMock):
"""Importer mock using PEP 451 APIs."""
def find_spec(self, fullname, path=None, parent=None):
try:
module = self.modules[fullname]
except KeyError:
return None
is_package = hasattr(module, '__path__')
spec = util.spec_from_file_location(
fullname, module.__file__, loader=self,
submodule_search_locations=getattr(module, '__path__', None))
return spec
def create_module(self, spec):
if spec.name not in self.modules:
raise ImportError
return self.modules[spec.name]
def exec_module(self, module):
try:
self.module_code[module.__spec__.name]()
except KeyError:
pass
def writes_bytecode_files(fxn):
"""Decorator to protect sys.dont_write_bytecode from mutation and to skip
tests that require it to be set to False."""
if sys.dont_write_bytecode:
return lambda *args, **kwargs: None
@functools.wraps(fxn)
def wrapper(*args, **kwargs):
original = sys.dont_write_bytecode
sys.dont_write_bytecode = False
try:
to_return = fxn(*args, **kwargs)
finally:
sys.dont_write_bytecode = original
return to_return
return wrapper
def ensure_bytecode_path(bytecode_path):
"""Ensure that the __pycache__ directory for PEP 3147 pyc file exists.
:param bytecode_path: File system path to PEP 3147 pyc file.
"""
try:
os.mkdir(os.path.dirname(bytecode_path))
except OSError as error:
if error.errno != errno.EEXIST:
raise
@contextlib.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 returned by
tempfile.mkdtemp(). 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 = {}
state_manager = None
uncache_manager = None
try:
temp_dir = tempfile.mkdtemp()
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:
if state_manager is not None:
state_manager.__exit__(None, None, None)
if uncache_manager is not None:
uncache_manager.__exit__(None, None, None)
support.rmtree(temp_dir)
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