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cpython/Lib/test/support.py

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"""Supporting definitions for the Python regression tests."""
if __name__ != 'test.support':
raise ImportError('support must be imported from the test package')
import contextlib
import errno
import functools
import gc
import socket
import sys
import os
import platform
import shutil
import warnings
import unittest
import importlib
import collections.abc
import re
import subprocess
import imp
import time
import sysconfig
import logging.handlers
try:
import _thread
except ImportError:
_thread = None
__all__ = [
"Error", "TestFailed", "ResourceDenied", "import_module",
"verbose", "use_resources", "max_memuse", "record_original_stdout",
"get_original_stdout", "unload", "unlink", "rmtree", "forget",
"is_resource_enabled", "requires", "find_unused_port", "bind_port",
"is_jython", "TESTFN", "HOST", "SAVEDCWD", "temp_cwd",
"findfile", "sortdict", "check_syntax_error", "open_urlresource",
"check_warnings", "CleanImport", "EnvironmentVarGuard",
"TransientResource", "captured_output", "captured_stdout",
"time_out", "socket_peer_reset", "ioerror_peer_reset",
"run_with_locale", 'temp_umask', "transient_internet",
"set_memlimit", "bigmemtest", "bigaddrspacetest", "BasicTestRunner",
"run_unittest", "run_doctest", "threading_setup", "threading_cleanup",
"reap_children", "cpython_only", "check_impl_detail", "get_attribute",
"swap_item", "swap_attr", "requires_IEEE_754",
"TestHandler", "Matcher", "can_symlink", "skip_unless_symlink"]
class Error(Exception):
"""Base class for regression test exceptions."""
class TestFailed(Error):
"""Test failed."""
class ResourceDenied(unittest.SkipTest):
"""Test skipped because it requested a disallowed resource.
This is raised when a test calls requires() for a resource that
has not be enabled. It is used to distinguish between expected
and unexpected skips.
"""
@contextlib.contextmanager
def _ignore_deprecated_imports(ignore=True):
"""Context manager to suppress package and module deprecation
warnings when importing them.
If ignore is False, this context manager has no effect."""
if ignore:
with warnings.catch_warnings():
warnings.filterwarnings("ignore", ".+ (module|package)",
DeprecationWarning)
yield
else:
yield
def import_module(name, deprecated=False):
"""Import and return the module to be tested, raising SkipTest if
it is not available.
If deprecated is True, any module or package deprecation messages
will be suppressed."""
with _ignore_deprecated_imports(deprecated):
try:
return importlib.import_module(name)
except ImportError as msg:
raise unittest.SkipTest(str(msg))
def _save_and_remove_module(name, orig_modules):
"""Helper function to save and remove a module from sys.modules
Return value is True if the module was in sys.modules and
False otherwise."""
saved = True
try:
orig_modules[name] = sys.modules[name]
except KeyError:
saved = False
else:
del sys.modules[name]
return saved
def _save_and_block_module(name, orig_modules):
"""Helper function to save and block a module in sys.modules
Return value is True if the module was in sys.modules and
False otherwise."""
saved = True
try:
orig_modules[name] = sys.modules[name]
except KeyError:
saved = False
sys.modules[name] = None
return saved
def import_fresh_module(name, fresh=(), blocked=(), deprecated=False):
"""Imports and returns a module, deliberately bypassing the sys.modules cache
and importing a fresh copy of the module. Once the import is complete,
the sys.modules cache is restored to its original state.
Modules named in fresh are also imported anew if needed by the import.
Importing of modules named in blocked is prevented while the fresh import
takes place.
If deprecated is True, any module or package deprecation messages
will be suppressed."""
# NOTE: test_heapq and test_warnings include extra sanity checks to make
# sure that this utility function is working as expected
with _ignore_deprecated_imports(deprecated):
# Keep track of modules saved for later restoration as well
# as those which just need a blocking entry removed
orig_modules = {}
names_to_remove = []
_save_and_remove_module(name, orig_modules)
try:
for fresh_name in fresh:
_save_and_remove_module(fresh_name, orig_modules)
for blocked_name in blocked:
if not _save_and_block_module(blocked_name, orig_modules):
names_to_remove.append(blocked_name)
fresh_module = importlib.import_module(name)
finally:
for orig_name, module in orig_modules.items():
sys.modules[orig_name] = module
for name_to_remove in names_to_remove:
del sys.modules[name_to_remove]
return fresh_module
def get_attribute(obj, name):
"""Get an attribute, raising SkipTest if AttributeError is raised."""
try:
attribute = getattr(obj, name)
except AttributeError:
raise unittest.SkipTest("module %s has no attribute %s" % (
obj.__name__, name))
else:
return attribute
verbose = 1 # Flag set to 0 by regrtest.py
use_resources = None # Flag set to [] by regrtest.py
max_memuse = 0 # Disable bigmem tests (they will still be run with
# small sizes, to make sure they work.)
real_max_memuse = 0
# _original_stdout is meant to hold stdout at the time regrtest began.
# This may be "the real" stdout, or IDLE's emulation of stdout, or whatever.
# The point is to have some flavor of stdout the user can actually see.
_original_stdout = None
def record_original_stdout(stdout):
global _original_stdout
_original_stdout = stdout
def get_original_stdout():
return _original_stdout or sys.stdout
def unload(name):
try:
del sys.modules[name]
except KeyError:
pass
def unlink(filename):
try:
os.unlink(filename)
except OSError as error:
# The filename need not exist.
if error.errno not in (errno.ENOENT, errno.ENOTDIR):
raise
def rmtree(path):
try:
shutil.rmtree(path)
except OSError as error:
# Unix returns ENOENT, Windows returns ESRCH.
if error.errno not in (errno.ENOENT, errno.ESRCH):
raise
def make_legacy_pyc(source):
"""Move a PEP 3147 pyc/pyo file to its legacy pyc/pyo location.
The choice of .pyc or .pyo extension is done based on the __debug__ flag
value.
:param source: The file system path to the source file. The source file
does not need to exist, however the PEP 3147 pyc file must exist.
:return: The file system path to the legacy pyc file.
"""
pyc_file = imp.cache_from_source(source)
up_one = os.path.dirname(os.path.abspath(source))
legacy_pyc = os.path.join(up_one, source + ('c' if __debug__ else 'o'))
os.rename(pyc_file, legacy_pyc)
return legacy_pyc
def forget(modname):
"""'Forget' a module was ever imported.
This removes the module from sys.modules and deletes any PEP 3147 or
legacy .pyc and .pyo files.
"""
unload(modname)
for dirname in sys.path:
source = os.path.join(dirname, modname + '.py')
# It doesn't matter if they exist or not, unlink all possible
# combinations of PEP 3147 and legacy pyc and pyo files.
unlink(source + 'c')
unlink(source + 'o')
unlink(imp.cache_from_source(source, debug_override=True))
unlink(imp.cache_from_source(source, debug_override=False))
# On some platforms, should not run gui test even if it is allowed
# in `use_resources'.
if sys.platform.startswith('win'):
import ctypes
import ctypes.wintypes
def _is_gui_available():
UOI_FLAGS = 1
WSF_VISIBLE = 0x0001
class USEROBJECTFLAGS(ctypes.Structure):
_fields_ = [("fInherit", ctypes.wintypes.BOOL),
("fReserved", ctypes.wintypes.BOOL),
("dwFlags", ctypes.wintypes.DWORD)]
dll = ctypes.windll.user32
h = dll.GetProcessWindowStation()
if not h:
raise ctypes.WinError()
uof = USEROBJECTFLAGS()
needed = ctypes.wintypes.DWORD()
res = dll.GetUserObjectInformationW(h,
UOI_FLAGS,
ctypes.byref(uof),
ctypes.sizeof(uof),
ctypes.byref(needed))
if not res:
raise ctypes.WinError()
return bool(uof.dwFlags & WSF_VISIBLE)
else:
def _is_gui_available():
return True
def is_resource_enabled(resource):
"""Test whether a resource is enabled. Known resources are set by
regrtest.py."""
return use_resources is not None and resource in use_resources
def requires(resource, msg=None):
"""Raise ResourceDenied if the specified resource is not available.
If the caller's module is __main__ then automatically return True. The
possibility of False being returned occurs when regrtest.py is
executing.
"""
if resource == 'gui' and not _is_gui_available():
raise unittest.SkipTest("Cannot use the 'gui' resource")
# see if the caller's module is __main__ - if so, treat as if
# the resource was set
if sys._getframe(1).f_globals.get("__name__") == "__main__":
return
if not is_resource_enabled(resource):
if msg is None:
msg = "Use of the `%s' resource not enabled" % resource
raise ResourceDenied(msg)
HOST = 'localhost'
def find_unused_port(family=socket.AF_INET, socktype=socket.SOCK_STREAM):
"""Returns an unused port that should be suitable for binding. This is
achieved by creating a temporary socket with the same family and type as
the 'sock' parameter (default is AF_INET, SOCK_STREAM), and binding it to
the specified host address (defaults to 0.0.0.0) with the port set to 0,
eliciting an unused ephemeral port from the OS. The temporary socket is
then closed and deleted, and the ephemeral port is returned.
Either this method or bind_port() should be used for any tests where a
server socket needs to be bound to a particular port for the duration of
the test. Which one to use depends on whether the calling code is creating
a python socket, or if an unused port needs to be provided in a constructor
or passed to an external program (i.e. the -accept argument to openssl's
s_server mode). Always prefer bind_port() over find_unused_port() where
possible. Hard coded ports should *NEVER* be used. As soon as a server
socket is bound to a hard coded port, the ability to run multiple instances
of the test simultaneously on the same host is compromised, which makes the
test a ticking time bomb in a buildbot environment. On Unix buildbots, this
may simply manifest as a failed test, which can be recovered from without
intervention in most cases, but on Windows, the entire python process can
completely and utterly wedge, requiring someone to log in to the buildbot
and manually kill the affected process.
(This is easy to reproduce on Windows, unfortunately, and can be traced to
the SO_REUSEADDR socket option having different semantics on Windows versus
Unix/Linux. On Unix, you can't have two AF_INET SOCK_STREAM sockets bind,
listen and then accept connections on identical host/ports. An EADDRINUSE
socket.error will be raised at some point (depending on the platform and
the order bind and listen were called on each socket).
However, on Windows, if SO_REUSEADDR is set on the sockets, no EADDRINUSE
will ever be raised when attempting to bind two identical host/ports. When
accept() is called on each socket, the second caller's process will steal
the port from the first caller, leaving them both in an awkwardly wedged
state where they'll no longer respond to any signals or graceful kills, and
must be forcibly killed via OpenProcess()/TerminateProcess().
The solution on Windows is to use the SO_EXCLUSIVEADDRUSE socket option
instead of SO_REUSEADDR, which effectively affords the same semantics as
SO_REUSEADDR on Unix. Given the propensity of Unix developers in the Open
Source world compared to Windows ones, this is a common mistake. A quick
look over OpenSSL's 0.9.8g source shows that they use SO_REUSEADDR when
openssl.exe is called with the 's_server' option, for example. See
http://bugs.python.org/issue2550 for more info. The following site also
has a very thorough description about the implications of both REUSEADDR
and EXCLUSIVEADDRUSE on Windows:
http://msdn2.microsoft.com/en-us/library/ms740621(VS.85).aspx)
XXX: although this approach is a vast improvement on previous attempts to
elicit unused ports, it rests heavily on the assumption that the ephemeral
port returned to us by the OS won't immediately be dished back out to some
other process when we close and delete our temporary socket but before our
calling code has a chance to bind the returned port. We can deal with this
issue if/when we come across it.
"""
tempsock = socket.socket(family, socktype)
port = bind_port(tempsock)
tempsock.close()
del tempsock
return port
def bind_port(sock, host=HOST):
"""Bind the socket to a free port and return the port number. Relies on
ephemeral ports in order to ensure we are using an unbound port. This is
important as many tests may be running simultaneously, especially in a
buildbot environment. This method raises an exception if the sock.family
is AF_INET and sock.type is SOCK_STREAM, *and* the socket has SO_REUSEADDR
or SO_REUSEPORT set on it. Tests should *never* set these socket options
for TCP/IP sockets. The only case for setting these options is testing
multicasting via multiple UDP sockets.
Additionally, if the SO_EXCLUSIVEADDRUSE socket option is available (i.e.
on Windows), it will be set on the socket. This will prevent anyone else
from bind()'ing to our host/port for the duration of the test.
"""
if sock.family == socket.AF_INET and sock.type == socket.SOCK_STREAM:
if hasattr(socket, 'SO_REUSEADDR'):
if sock.getsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR) == 1:
raise TestFailed("tests should never set the SO_REUSEADDR " \
"socket option on TCP/IP sockets!")
if hasattr(socket, 'SO_REUSEPORT'):
if sock.getsockopt(socket.SOL_SOCKET, socket.SO_REUSEPORT) == 1:
raise TestFailed("tests should never set the SO_REUSEPORT " \
"socket option on TCP/IP sockets!")
if hasattr(socket, 'SO_EXCLUSIVEADDRUSE'):
sock.setsockopt(socket.SOL_SOCKET, socket.SO_EXCLUSIVEADDRUSE, 1)
sock.bind((host, 0))
port = sock.getsockname()[1]
return port
# decorator for skipping tests on non-IEEE 754 platforms
requires_IEEE_754 = unittest.skipUnless(
float.__getformat__("double").startswith("IEEE"),
"test requires IEEE 754 doubles")
is_jython = sys.platform.startswith('java')
# Filename used for testing
if os.name == 'java':
# Jython disallows @ in module names
TESTFN = '$test'
else:
TESTFN = '@test'
# Disambiguate TESTFN for parallel testing, while letting it remain a valid
# module name.
TESTFN = "{}_{}_tmp".format(TESTFN, os.getpid())
# TESTFN_UNICODE is a non-ascii filename
TESTFN_UNICODE = TESTFN + "-\xe0\xf2\u0258\u0141\u011f"
if sys.platform == 'darwin':
# In Mac OS X's VFS API file names are, by definition, canonically
# decomposed Unicode, encoded using UTF-8. See QA1173:
# http://developer.apple.com/mac/library/qa/qa2001/qa1173.html
import unicodedata
TESTFN_UNICODE = unicodedata.normalize('NFD', TESTFN_UNICODE)
TESTFN_ENCODING = sys.getfilesystemencoding()
# TESTFN_UNENCODABLE is a filename (str type) that should *not* be able to be
# encoded by the filesystem encoding (in strict mode). It can be None if we
# cannot generate such filename.
TESTFN_UNENCODABLE = None
if os.name in ('nt', 'ce'):
# skip win32s (0) or Windows 9x/ME (1)
if sys.getwindowsversion().platform >= 2:
# Different kinds of characters from various languages to minimize the
# probability that the whole name is encodable to MBCS (issue #9819)
TESTFN_UNENCODABLE = TESTFN + "-\u5171\u0141\u2661\u0363\uDC80"
try:
TESTFN_UNENCODABLE.encode(TESTFN_ENCODING)
except UnicodeEncodeError:
pass
else:
print('WARNING: The filename %r CAN be encoded by the filesystem encoding (%s). '
'Unicode filename tests may not be effective'
% (TESTFN_UNENCODABLE, TESTFN_ENCODING))
TESTFN_UNENCODABLE = None
# Mac OS X denies unencodable filenames (invalid utf-8)
elif sys.platform != 'darwin':
try:
# ascii and utf-8 cannot encode the byte 0xff
b'\xff'.decode(TESTFN_ENCODING)
except UnicodeDecodeError:
# 0xff will be encoded using the surrogate character u+DCFF
TESTFN_UNENCODABLE = TESTFN \
+ b'-\xff'.decode(TESTFN_ENCODING, 'surrogateescape')
else:
# File system encoding (eg. ISO-8859-* encodings) can encode
# the byte 0xff. Skip some unicode filename tests.
pass
# Save the initial cwd
SAVEDCWD = os.getcwd()
@contextlib.contextmanager
def temp_cwd(name='tempcwd', quiet=False, path=None):
"""
Context manager that temporarily changes the CWD.
An existing path may be provided as *path*, in which case this
function makes no changes to the file system.
Otherwise, the new CWD is created in the current directory and it's
named *name*. If *quiet* is False (default) and it's not possible to
create or change the CWD, an error is raised. If it's True, only a
warning is raised and the original CWD is used.
"""
saved_dir = os.getcwd()
is_temporary = False
if path is None:
path = name
try:
os.mkdir(name)
is_temporary = True
except OSError:
if not quiet:
raise
warnings.warn('tests may fail, unable to create temp CWD ' + name,
RuntimeWarning, stacklevel=3)
try:
os.chdir(path)
except OSError:
if not quiet:
raise
warnings.warn('tests may fail, unable to change the CWD to ' + name,
RuntimeWarning, stacklevel=3)
try:
yield os.getcwd()
finally:
os.chdir(saved_dir)
if is_temporary:
rmtree(name)
@contextlib.contextmanager
def temp_umask(umask):
"""Context manager that temporarily sets the process umask."""
oldmask = os.umask(umask)
try:
yield
finally:
os.umask(oldmask)
def findfile(file, here=__file__, subdir=None):
"""Try to find a file on sys.path and the working directory. If it is not
found the argument passed to the function is returned (this does not
necessarily signal failure; could still be the legitimate path)."""
if os.path.isabs(file):
return file
if subdir is not None:
file = os.path.join(subdir, file)
path = sys.path
path = [os.path.dirname(here)] + path
for dn in path:
fn = os.path.join(dn, file)
if os.path.exists(fn): return fn
return file
def sortdict(dict):
"Like repr(dict), but in sorted order."
items = sorted(dict.items())
reprpairs = ["%r: %r" % pair for pair in items]
withcommas = ", ".join(reprpairs)
return "{%s}" % withcommas
def make_bad_fd():
"""
Create an invalid file descriptor by opening and closing a file and return
its fd.
"""
file = open(TESTFN, "wb")
try:
return file.fileno()
finally:
file.close()
unlink(TESTFN)
def check_syntax_error(testcase, statement):
testcase.assertRaises(SyntaxError, compile, statement,
'<test string>', 'exec')
def open_urlresource(url, *args, **kw):
import urllib.request, urllib.parse
check = kw.pop('check', None)
filename = urllib.parse.urlparse(url)[2].split('/')[-1] # '/': it's URL!
fn = os.path.join(os.path.dirname(__file__), "data", filename)
def check_valid_file(fn):
f = open(fn, *args, **kw)
if check is None:
return f
elif check(f):
f.seek(0)
return f
f.close()
if os.path.exists(fn):
f = check_valid_file(fn)
if f is not None:
return f
unlink(fn)
# Verify the requirement before downloading the file
requires('urlfetch')
print('\tfetching %s ...' % url, file=get_original_stdout())
f = urllib.request.urlopen(url, timeout=15)
try:
with open(fn, "wb") as out:
s = f.read()
while s:
out.write(s)
s = f.read()
finally:
f.close()
f = check_valid_file(fn)
if f is not None:
return f
raise TestFailed('invalid resource "%s"' % fn)
class WarningsRecorder(object):
"""Convenience wrapper for the warnings list returned on
entry to the warnings.catch_warnings() context manager.
"""
def __init__(self, warnings_list):
self._warnings = warnings_list
self._last = 0
def __getattr__(self, attr):
if len(self._warnings) > self._last:
return getattr(self._warnings[-1], attr)
elif attr in warnings.WarningMessage._WARNING_DETAILS:
return None
raise AttributeError("%r has no attribute %r" % (self, attr))
@property
def warnings(self):
return self._warnings[self._last:]
def reset(self):
self._last = len(self._warnings)
def _filterwarnings(filters, quiet=False):
"""Catch the warnings, then check if all the expected
warnings have been raised and re-raise unexpected warnings.
If 'quiet' is True, only re-raise the unexpected warnings.
"""
# Clear the warning registry of the calling module
# in order to re-raise the warnings.
frame = sys._getframe(2)
registry = frame.f_globals.get('__warningregistry__')
if registry:
registry.clear()
with warnings.catch_warnings(record=True) as w:
# Set filter "always" to record all warnings. Because
# test_warnings swap the module, we need to look up in
# the sys.modules dictionary.
sys.modules['warnings'].simplefilter("always")
yield WarningsRecorder(w)
# Filter the recorded warnings
reraise = list(w)
missing = []
for msg, cat in filters:
seen = False
for w in reraise[:]:
warning = w.message
# Filter out the matching messages
if (re.match(msg, str(warning), re.I) and
issubclass(warning.__class__, cat)):
seen = True
reraise.remove(w)
if not seen and not quiet:
# This filter caught nothing
missing.append((msg, cat.__name__))
if reraise:
raise AssertionError("unhandled warning %s" % reraise[0])
if missing:
raise AssertionError("filter (%r, %s) did not catch any warning" %
missing[0])
@contextlib.contextmanager
def check_warnings(*filters, **kwargs):
"""Context manager to silence warnings.
Accept 2-tuples as positional arguments:
("message regexp", WarningCategory)
Optional argument:
- if 'quiet' is True, it does not fail if a filter catches nothing
(default True without argument,
default False if some filters are defined)
Without argument, it defaults to:
check_warnings(("", Warning), quiet=True)
"""
quiet = kwargs.get('quiet')
if not filters:
filters = (("", Warning),)
# Preserve backward compatibility
if quiet is None:
quiet = True
return _filterwarnings(filters, quiet)
class CleanImport(object):
"""Context manager to force import to return a new module reference.
This is useful for testing module-level behaviours, such as
the emission of a DeprecationWarning on import.
Use like this:
with CleanImport("foo"):
importlib.import_module("foo") # new reference
"""
def __init__(self, *module_names):
self.original_modules = sys.modules.copy()
for module_name in module_names:
if module_name in sys.modules:
module = sys.modules[module_name]
# It is possible that module_name is just an alias for
# another module (e.g. stub for modules renamed in 3.x).
# In that case, we also need delete the real module to clear
# the import cache.
if module.__name__ != module_name:
del sys.modules[module.__name__]
del sys.modules[module_name]
def __enter__(self):
return self
def __exit__(self, *ignore_exc):
sys.modules.update(self.original_modules)
class EnvironmentVarGuard(collections.abc.MutableMapping):
"""Class to help protect the environment variable properly. Can be used as
a context manager."""
def __init__(self):
self._environ = os.environ
self._changed = {}
def __getitem__(self, envvar):
return self._environ[envvar]
def __setitem__(self, envvar, value):
# Remember the initial value on the first access
if envvar not in self._changed:
self._changed[envvar] = self._environ.get(envvar)
self._environ[envvar] = value
def __delitem__(self, envvar):
# Remember the initial value on the first access
if envvar not in self._changed:
self._changed[envvar] = self._environ.get(envvar)
if envvar in self._environ:
del self._environ[envvar]
def keys(self):
return self._environ.keys()
def __iter__(self):
return iter(self._environ)
def __len__(self):
return len(self._environ)
def set(self, envvar, value):
self[envvar] = value
def unset(self, envvar):
del self[envvar]
def __enter__(self):
return self
def __exit__(self, *ignore_exc):
for (k, v) in self._changed.items():
if v is None:
if k in self._environ:
del self._environ[k]
else:
self._environ[k] = v
os.environ = self._environ
class DirsOnSysPath(object):
"""Context manager to temporarily add directories to sys.path.
This makes a copy of sys.path, appends any directories given
as positional arguments, then reverts sys.path to the copied
settings when the context ends.
Note that *all* sys.path modifications in the body of the
context manager, including replacement of the object,
will be reverted at the end of the block.
"""
def __init__(self, *paths):
self.original_value = sys.path[:]
self.original_object = sys.path
sys.path.extend(paths)
def __enter__(self):
return self
def __exit__(self, *ignore_exc):
sys.path = self.original_object
sys.path[:] = self.original_value
class TransientResource(object):
"""Raise ResourceDenied if an exception is raised while the context manager
is in effect that matches the specified exception and attributes."""
def __init__(self, exc, **kwargs):
self.exc = exc
self.attrs = kwargs
def __enter__(self):
return self
def __exit__(self, type_=None, value=None, traceback=None):
"""If type_ is a subclass of self.exc and value has attributes matching
self.attrs, raise ResourceDenied. Otherwise let the exception
propagate (if any)."""
if type_ is not None and issubclass(self.exc, type_):
for attr, attr_value in self.attrs.items():
if not hasattr(value, attr):
break
if getattr(value, attr) != attr_value:
break
else:
raise ResourceDenied("an optional resource is not available")
# Context managers that raise ResourceDenied when various issues
# with the Internet connection manifest themselves as exceptions.
# XXX deprecate these and use transient_internet() instead
time_out = TransientResource(IOError, errno=errno.ETIMEDOUT)
socket_peer_reset = TransientResource(socket.error, errno=errno.ECONNRESET)
ioerror_peer_reset = TransientResource(IOError, errno=errno.ECONNRESET)
@contextlib.contextmanager
def transient_internet(resource_name, *, timeout=30.0, errnos=()):
"""Return a context manager that raises ResourceDenied when various issues
with the Internet connection manifest themselves as exceptions."""
default_errnos = [
('ECONNREFUSED', 111),
('ECONNRESET', 104),
('EHOSTUNREACH', 113),
('ENETUNREACH', 101),
('ETIMEDOUT', 110),
]
default_gai_errnos = [
('EAI_NONAME', -2),
('EAI_NODATA', -5),
]
denied = ResourceDenied("Resource '%s' is not available" % resource_name)
captured_errnos = errnos
gai_errnos = []
if not captured_errnos:
captured_errnos = [getattr(errno, name, num)
for (name, num) in default_errnos]
gai_errnos = [getattr(socket, name, num)
for (name, num) in default_gai_errnos]
def filter_error(err):
n = getattr(err, 'errno', None)
if (isinstance(err, socket.timeout) or
(isinstance(err, socket.gaierror) and n in gai_errnos) or
n in captured_errnos):
if not verbose:
sys.stderr.write(denied.args[0] + "\n")
raise denied from err
old_timeout = socket.getdefaulttimeout()
try:
if timeout is not None:
socket.setdefaulttimeout(timeout)
yield
except IOError as err:
# urllib can wrap original socket errors multiple times (!), we must
# unwrap to get at the original error.
while True:
a = err.args
if len(a) >= 1 and isinstance(a[0], IOError):
err = a[0]
# The error can also be wrapped as args[1]:
# except socket.error as msg:
# raise IOError('socket error', msg).with_traceback(sys.exc_info()[2])
elif len(a) >= 2 and isinstance(a[1], IOError):
err = a[1]
else:
break
filter_error(err)
raise
# XXX should we catch generic exceptions and look for their
# __cause__ or __context__?
finally:
socket.setdefaulttimeout(old_timeout)
@contextlib.contextmanager
def captured_output(stream_name):
"""Run the 'with' statement body using a StringIO object in place of a
specific attribute on the sys module.
Example use (with 'stream_name=stdout')::
with captured_stdout() as s:
print("hello")
assert s.getvalue() == "hello"
"""
import io
orig_stdout = getattr(sys, stream_name)
setattr(sys, stream_name, io.StringIO())
try:
yield getattr(sys, stream_name)
finally:
setattr(sys, stream_name, orig_stdout)
def captured_stdout():
return captured_output("stdout")
def captured_stderr():
return captured_output("stderr")
def captured_stdin():
return captured_output("stdin")
def gc_collect():
"""Force as many objects as possible to be collected.
In non-CPython implementations of Python, this is needed because timely
deallocation is not guaranteed by the garbage collector. (Even in CPython
this can be the case in case of reference cycles.) This means that __del__
methods may be called later than expected and weakrefs may remain alive for
longer than expected. This function tries its best to force all garbage
objects to disappear.
"""
gc.collect()
if is_jython:
time.sleep(0.1)
gc.collect()
gc.collect()
def python_is_optimized():
"""Find if Python was built with optimizations."""
cflags = sysconfig.get_config_var('PY_CFLAGS') or ''
final_opt = ""
for opt in cflags.split():
if opt.startswith('-O'):
final_opt = opt
return final_opt and final_opt != '-O0'
#=======================================================================
# Decorator for running a function in a different locale, correctly resetting
# it afterwards.
def run_with_locale(catstr, *locales):
def decorator(func):
def inner(*args, **kwds):
try:
import locale
category = getattr(locale, catstr)
orig_locale = locale.setlocale(category)
except AttributeError:
# if the test author gives us an invalid category string
raise
except:
# cannot retrieve original locale, so do nothing
locale = orig_locale = None
else:
for loc in locales:
try:
locale.setlocale(category, loc)
break
except:
pass
# now run the function, resetting the locale on exceptions
try:
return func(*args, **kwds)
finally:
if locale and orig_locale:
locale.setlocale(category, orig_locale)
inner.__name__ = func.__name__
inner.__doc__ = func.__doc__
return inner
return decorator
#=======================================================================
# Big-memory-test support. Separate from 'resources' because memory use
# should be configurable.
# Some handy shorthands. Note that these are used for byte-limits as well
# as size-limits, in the various bigmem tests
_1M = 1024*1024
_1G = 1024 * _1M
_2G = 2 * _1G
_4G = 4 * _1G
MAX_Py_ssize_t = sys.maxsize
def set_memlimit(limit):
global max_memuse
global real_max_memuse
sizes = {
'k': 1024,
'm': _1M,
'g': _1G,
't': 1024*_1G,
}
m = re.match(r'(\d+(\.\d+)?) (K|M|G|T)b?$', limit,
re.IGNORECASE | re.VERBOSE)
if m is None:
raise ValueError('Invalid memory limit %r' % (limit,))
memlimit = int(float(m.group(1)) * sizes[m.group(3).lower()])
real_max_memuse = memlimit
if memlimit > MAX_Py_ssize_t:
memlimit = MAX_Py_ssize_t
if memlimit < _2G - 1:
raise ValueError('Memory limit %r too low to be useful' % (limit,))
max_memuse = memlimit
def bigmemtest(minsize, memuse):
"""Decorator for bigmem tests.
'minsize' is the minimum useful size for the test (in arbitrary,
test-interpreted units.) 'memuse' is the number of 'bytes per size' for
the test, or a good estimate of it.
The decorator tries to guess a good value for 'size' and passes it to
the decorated test function. If minsize * memuse is more than the
allowed memory use (as defined by max_memuse), the test is skipped.
Otherwise, minsize is adjusted upward to use up to max_memuse.
"""
def decorator(f):
def wrapper(self):
# Retrieve values in case someone decided to adjust them
minsize = wrapper.minsize
memuse = wrapper.memuse
if not max_memuse:
# If max_memuse is 0 (the default),
# we still want to run the tests with size set to a few kb,
# to make sure they work. We still want to avoid using
# too much memory, though, but we do that noisily.
maxsize = 5147
self.assertFalse(maxsize * memuse > 20 * _1M)
else:
maxsize = int(max_memuse / memuse)
if maxsize < minsize:
raise unittest.SkipTest(
"not enough memory: %.1fG minimum needed"
% (minsize * memuse / (1024 ** 3)))
return f(self, maxsize)
wrapper.minsize = minsize
wrapper.memuse = memuse
return wrapper
return decorator
def precisionbigmemtest(size, memuse):
def decorator(f):
def wrapper(self):
size = wrapper.size
memuse = wrapper.memuse
if not real_max_memuse:
maxsize = 5147
else:
maxsize = size
if real_max_memuse and real_max_memuse < maxsize * memuse:
raise unittest.SkipTest(
"not enough memory: %.1fG minimum needed"
% (size * memuse / (1024 ** 3)))
return f(self, maxsize)
wrapper.size = size
wrapper.memuse = memuse
return wrapper
return decorator
def bigaddrspacetest(f):
"""Decorator for tests that fill the address space."""
def wrapper(self):
if max_memuse < MAX_Py_ssize_t:
if MAX_Py_ssize_t >= 2**63 - 1 and max_memuse >= 2**31:
raise unittest.SkipTest(
"not enough memory: try a 32-bit build instead")
else:
raise unittest.SkipTest(
"not enough memory: %.1fG minimum needed"
% (MAX_Py_ssize_t / (1024 ** 3)))
else:
return f(self)
return wrapper
#=======================================================================
# unittest integration.
class BasicTestRunner:
def run(self, test):
result = unittest.TestResult()
test(result)
return result
def _id(obj):
return obj
def requires_resource(resource):
if resource == 'gui' and not _is_gui_available():
return unittest.skip("resource 'gui' is not available")
if is_resource_enabled(resource):
return _id
else:
return unittest.skip("resource {0!r} is not enabled".format(resource))
def cpython_only(test):
"""
Decorator for tests only applicable on CPython.
"""
return impl_detail(cpython=True)(test)
def impl_detail(msg=None, **guards):
if check_impl_detail(**guards):
return _id
if msg is None:
guardnames, default = _parse_guards(guards)
if default:
msg = "implementation detail not available on {0}"
else:
msg = "implementation detail specific to {0}"
guardnames = sorted(guardnames.keys())
msg = msg.format(' or '.join(guardnames))
return unittest.skip(msg)
def _parse_guards(guards):
# Returns a tuple ({platform_name: run_me}, default_value)
if not guards:
return ({'cpython': True}, False)
is_true = list(guards.values())[0]
assert list(guards.values()) == [is_true] * len(guards) # all True or all False
return (guards, not is_true)
# Use the following check to guard CPython's implementation-specific tests --
# or to run them only on the implementation(s) guarded by the arguments.
def check_impl_detail(**guards):
"""This function returns True or False depending on the host platform.
Examples:
if check_impl_detail(): # only on CPython (default)
if check_impl_detail(jython=True): # only on Jython
if check_impl_detail(cpython=False): # everywhere except on CPython
"""
guards, default = _parse_guards(guards)
return guards.get(platform.python_implementation().lower(), default)
def no_tracing(func):
"""Decorator to temporarily turn off tracing for the duration of a test."""
if not hasattr(sys, 'gettrace'):
return func
else:
@functools.wraps(func)
def wrapper(*args, **kwargs):
original_trace = sys.gettrace()
try:
sys.settrace(None)
return func(*args, **kwargs)
finally:
sys.settrace(original_trace)
return wrapper
def refcount_test(test):
"""Decorator for tests which involve reference counting.
To start, the decorator does not run the test if is not run by CPython.
After that, any trace function is unset during the test to prevent
unexpected refcounts caused by the trace function.
"""
return no_tracing(cpython_only(test))
def _run_suite(suite):
"""Run tests from a unittest.TestSuite-derived class."""
if verbose:
runner = unittest.TextTestRunner(sys.stdout, verbosity=2)
else:
runner = BasicTestRunner()
result = runner.run(suite)
if not result.wasSuccessful():
if len(result.errors) == 1 and not result.failures:
err = result.errors[0][1]
elif len(result.failures) == 1 and not result.errors:
err = result.failures[0][1]
else:
err = "multiple errors occurred"
if not verbose: err += "; run in verbose mode for details"
raise TestFailed(err)
def run_unittest(*classes):
"""Run tests from unittest.TestCase-derived classes."""
valid_types = (unittest.TestSuite, unittest.TestCase)
suite = unittest.TestSuite()
for cls in classes:
if isinstance(cls, str):
if cls in sys.modules:
suite.addTest(unittest.findTestCases(sys.modules[cls]))
else:
raise ValueError("str arguments must be keys in sys.modules")
elif isinstance(cls, valid_types):
suite.addTest(cls)
else:
suite.addTest(unittest.makeSuite(cls))
_run_suite(suite)
#=======================================================================
# doctest driver.
def run_doctest(module, verbosity=None):
"""Run doctest on the given module. Return (#failures, #tests).
If optional argument verbosity is not specified (or is None), pass
support's belief about verbosity on to doctest. Else doctest's
usual behavior is used (it searches sys.argv for -v).
"""
import doctest
if verbosity is None:
verbosity = verbose
else:
verbosity = None
# Direct doctest output (normally just errors) to real stdout; doctest
# output shouldn't be compared by regrtest.
save_stdout = sys.stdout
sys.stdout = get_original_stdout()
try:
f, t = doctest.testmod(module, verbose=verbosity)
if f:
raise TestFailed("%d of %d doctests failed" % (f, t))
finally:
sys.stdout = save_stdout
if verbose:
print('doctest (%s) ... %d tests with zero failures' %
(module.__name__, t))
return f, t
#=======================================================================
# Support for saving and restoring the imported modules.
def modules_setup():
return sys.modules.copy(),
def modules_cleanup(oldmodules):
# Encoders/decoders are registered permanently within the internal
# codec cache. If we destroy the corresponding modules their
# globals will be set to None which will trip up the cached functions.
encodings = [(k, v) for k, v in sys.modules.items()
if k.startswith('encodings.')]
sys.modules.clear()
sys.modules.update(encodings)
# XXX: This kind of problem can affect more than just encodings. In particular
# extension modules (such as _ssl) don't cope with reloading properly.
# Really, test modules should be cleaning out the test specific modules they
# know they added (ala test_runpy) rather than relying on this function (as
# test_importhooks and test_pkg do currently).
# Implicitly imported *real* modules should be left alone (see issue 10556).
sys.modules.update(oldmodules)
#=======================================================================
# Threading support to prevent reporting refleaks when running regrtest.py -R
# NOTE: we use thread._count() rather than threading.enumerate() (or the
# moral equivalent thereof) because a threading.Thread object is still alive
# until its __bootstrap() method has returned, even after it has been
# unregistered from the threading module.
# thread._count(), on the other hand, only gets decremented *after* the
# __bootstrap() method has returned, which gives us reliable reference counts
# at the end of a test run.
def threading_setup():
if _thread:
return _thread._count(),
else:
return 1,
def threading_cleanup(nb_threads):
if not _thread:
return
_MAX_COUNT = 10
for count in range(_MAX_COUNT):
n = _thread._count()
if n == nb_threads:
break
time.sleep(0.1)
# XXX print a warning in case of failure?
def reap_threads(func):
"""Use this function when threads are being used. This will
ensure that the threads are cleaned up even when the test fails.
If threading is unavailable this function does nothing.
"""
if not _thread:
return func
@functools.wraps(func)
def decorator(*args):
key = threading_setup()
try:
return func(*args)
finally:
threading_cleanup(*key)
return decorator
def reap_children():
"""Use this function at the end of test_main() whenever sub-processes
are started. This will help ensure that no extra children (zombies)
stick around to hog resources and create problems when looking
for refleaks.
"""
# Reap all our dead child processes so we don't leave zombies around.
# These hog resources and might be causing some of the buildbots to die.
if hasattr(os, 'waitpid'):
any_process = -1
while True:
try:
# This will raise an exception on Windows. That's ok.
pid, status = os.waitpid(any_process, os.WNOHANG)
if pid == 0:
break
except:
break
@contextlib.contextmanager
def swap_attr(obj, attr, new_val):
"""Temporary swap out an attribute with a new object.
Usage:
with swap_attr(obj, "attr", 5):
...
This will set obj.attr to 5 for the duration of the with: block,
restoring the old value at the end of the block. If `attr` doesn't
exist on `obj`, it will be created and then deleted at the end of the
block.
"""
if hasattr(obj, attr):
real_val = getattr(obj, attr)
setattr(obj, attr, new_val)
try:
yield
finally:
setattr(obj, attr, real_val)
else:
setattr(obj, attr, new_val)
try:
yield
finally:
delattr(obj, attr)
@contextlib.contextmanager
def swap_item(obj, item, new_val):
"""Temporary swap out an item with a new object.
Usage:
with swap_item(obj, "item", 5):
...
This will set obj["item"] to 5 for the duration of the with: block,
restoring the old value at the end of the block. If `item` doesn't
exist on `obj`, it will be created and then deleted at the end of the
block.
"""
if item in obj:
real_val = obj[item]
obj[item] = new_val
try:
yield
finally:
obj[item] = real_val
else:
obj[item] = new_val
try:
yield
finally:
del obj[item]
def strip_python_stderr(stderr):
"""Strip the stderr of a Python process from potential debug output
emitted by the interpreter.
This will typically be run on the result of the communicate() method
of a subprocess.Popen object.
"""
stderr = re.sub(br"\[\d+ refs\]\r?\n?$", b"", stderr).strip()
return stderr
def args_from_interpreter_flags():
"""Return a list of command-line arguments reproducing the current
settings in sys.flags."""
flag_opt_map = {
'bytes_warning': 'b',
'dont_write_bytecode': 'B',
'ignore_environment': 'E',
'no_user_site': 's',
'no_site': 'S',
'optimize': 'O',
'verbose': 'v',
}
args = []
for flag, opt in flag_opt_map.items():
v = getattr(sys.flags, flag)
if v > 0:
args.append('-' + opt * v)
return args
#============================================================
# Support for assertions about logging.
#============================================================
class TestHandler(logging.handlers.BufferingHandler):
def __init__(self, matcher):
# BufferingHandler takes a "capacity" argument
# so as to know when to flush. As we're overriding
# shouldFlush anyway, we can set a capacity of zero.
# You can call flush() manually to clear out the
# buffer.
logging.handlers.BufferingHandler.__init__(self, 0)
self.matcher = matcher
def shouldFlush(self):
return False
def emit(self, record):
self.format(record)
self.buffer.append(record.__dict__)
def matches(self, **kwargs):
"""
Look for a saved dict whose keys/values match the supplied arguments.
"""
result = False
for d in self.buffer:
if self.matcher.matches(d, **kwargs):
result = True
break
return result
class Matcher(object):
_partial_matches = ('msg', 'message')
def matches(self, d, **kwargs):
"""
Try to match a single dict with the supplied arguments.
Keys whose values are strings and which are in self._partial_matches
will be checked for partial (i.e. substring) matches. You can extend
this scheme to (for example) do regular expression matching, etc.
"""
result = True
for k in kwargs:
v = kwargs[k]
dv = d.get(k)
if not self.match_value(k, dv, v):
result = False
break
return result
def match_value(self, k, dv, v):
"""
Try to match a single stored value (dv) with a supplied value (v).
"""
if type(v) != type(dv):
result = False
elif type(dv) is not str or k not in self._partial_matches:
result = (v == dv)
else:
result = dv.find(v) >= 0
return result
_can_symlink = None
def can_symlink():
global _can_symlink
if _can_symlink is not None:
return _can_symlink
try:
os.symlink(TESTFN, TESTFN + "can_symlink")
can = True
except (OSError, NotImplementedError):
can = False
_can_symlink = can
return can
def skip_unless_symlink(test):
"""Skip decorator for tests that require functional symlink"""
ok = can_symlink()
msg = "Requires functional symlink implementation"
return test if ok else unittest.skip(msg)(test)
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