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"""Supporting definitions for the Python regression tests."""
if __name__ != '':
raise ImportError('support must be imported from the test package')
import contextlib
import errno
import faulthandler
import fnmatch
import functools
import gc
import importlib
import importlib.util
import logging.handlers
import nntplib
import os
import platform
import re
import shutil
import socket
import stat
import struct
import subprocess
import sys
import sysconfig
import tempfile
import time
import unittest
import urllib.error
import warnings
import _thread, threading
except ImportError:
_thread = None
threading = None
import multiprocessing.process
except ImportError:
multiprocessing = None
import zlib
except ImportError:
zlib = None
import gzip
except ImportError:
gzip = None
import bz2
except ImportError:
bz2 = None
import lzma
except ImportError:
lzma = None
import resource
except ImportError:
resource = None
__all__ = [
# globals
"PIPE_MAX_SIZE", "verbose", "max_memuse", "use_resources", "failfast",
# exceptions
"Error", "TestFailed", "ResourceDenied",
# imports
"import_module", "import_fresh_module", "CleanImport",
# modules
"unload", "forget",
# io
"record_original_stdout", "get_original_stdout", "captured_stdout",
"captured_stdin", "captured_stderr",
# filesystem
"TESTFN", "SAVEDCWD", "unlink", "rmtree", "temp_cwd", "findfile",
"create_empty_file", "can_symlink", "fs_is_case_insensitive",
# unittest
"is_resource_enabled", "requires", "requires_freebsd_version",
"requires_linux_version", "requires_mac_ver", "check_syntax_error",
"TransientResource", "time_out", "socket_peer_reset", "ioerror_peer_reset",
"transient_internet", "BasicTestRunner", "run_unittest", "run_doctest",
"skip_unless_symlink", "requires_gzip", "requires_bz2", "requires_lzma",
"bigmemtest", "bigaddrspacetest", "cpython_only", "get_attribute",
"requires_IEEE_754", "skip_unless_xattr", "requires_zlib",
"anticipate_failure", "load_package_tests",
# sys
"is_jython", "check_impl_detail",
# network
"HOST", "IPV6_ENABLED", "find_unused_port", "bind_port", "open_urlresource",
# processes
'temp_umask', "reap_children",
# logging
# threads
"threading_setup", "threading_cleanup", "reap_threads", "start_threads",
# miscellaneous
"check_warnings", "EnvironmentVarGuard", "run_with_locale", "swap_item",
"swap_attr", "Matcher", "set_memlimit", "SuppressCrashReport", "sortdict",
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.
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)",
def import_module(name, deprecated=False, *, required_on=()):
"""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. If a module is required on a platform but optional for
others, set required_on to an iterable of platform prefixes which will be
compared against sys.platform.
with _ignore_deprecated_imports(deprecated):
return importlib.import_module(name)
except ImportError as msg:
if sys.platform.startswith(tuple(required_on)):
raise unittest.SkipTest(str(msg))
def _save_and_remove_module(name, orig_modules):
"""Helper function to save and remove a module from sys.modules
Raise ImportError if the module can't be imported.
# try to import the module and raise an error if it can't be imported
if name not in sys.modules:
del sys.modules[name]
for modname in list(sys.modules):
if modname == name or modname.startswith(name + '.'):
orig_modules[modname] = sys.modules[modname]
del sys.modules[modname]
def _save_and_block_module(name, orig_modules):
"""Helper function to save and block a module in sys.modules
Return True if the module was in sys.modules, False otherwise.
saved = True
orig_modules[name] = sys.modules[name]
except KeyError:
saved = False
sys.modules[name] = None
return saved
def anticipate_failure(condition):
"""Decorator to mark a test that is known to be broken in some cases
Any use of this decorator should have a comment identifying the
associated tracker issue.
if condition:
return unittest.expectedFailure
return lambda f: f
def load_package_tests(pkg_dir, loader, standard_tests, pattern):
"""Generic load_tests implementation for simple test packages.
Most packages can implement load_tests using this function as follows:
def load_tests(*args):
return load_package_tests(os.path.dirname(__file__), *args)
if pattern is None:
pattern = "test*"
top_dir = os.path.dirname( # Lib
os.path.dirname( # test
os.path.dirname(__file__))) # support
package_tests =,
return standard_tests
def import_fresh_module(name, fresh=(), blocked=(), deprecated=False):
"""Import and return a module, deliberately bypassing sys.modules.
This function imports and returns a fresh copy of the named Python module
by removing the named module from sys.modules before doing the import.
Note that unlike reload, the original module is not affected by
this operation.
*fresh* is an iterable of additional module names that are also removed
from the sys.modules cache before doing the import.
*blocked* is an iterable of module names that are replaced with None
in the module cache during the import to ensure that attempts to import
them raise ImportError.
The named module and any modules named in the *fresh* and *blocked*
parameters are saved before starting the import and then reinserted into
sys.modules when the fresh import is complete.
Module and package deprecation messages are suppressed during this import
if *deprecated* is True.
This function will raise ImportError if the named module cannot be
# NOTE: test_heapq, test_json 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)
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):
fresh_module = importlib.import_module(name)
except ImportError:
fresh_module = None
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."""
attribute = getattr(obj, name)
except AttributeError:
raise unittest.SkipTest("object %r has no attribute %r" % (obj, name))
return attribute
verbose = 1 # Flag set to 0 by
use_resources = None # Flag set to [] by
max_memuse = 0 # Disable bigmem tests (they will still be run with
# small sizes, to make sure they work.)
real_max_memuse = 0
failfast = False
match_tests = None
# _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):
del sys.modules[name]
except KeyError:
if sys.platform.startswith("win"):
def _waitfor(func, pathname, waitall=False):
# Perform the operation
# Now setup the wait loop
if waitall:
dirname = pathname
dirname, name = os.path.split(pathname)
dirname = dirname or '.'
# Check for `pathname` to be removed from the filesystem.
# The exponential backoff of the timeout amounts to a total
# of ~1 second after which the deletion is probably an error
# anyway.
# Testing on an i7@4.3GHz shows that usually only 1 iteration is
# required when contention occurs.
timeout = 0.001
while timeout < 1.0:
# Note we are only testing for the existence of the file(s) in
# the contents of the directory regardless of any security or
# access rights. If we have made it this far, we have sufficient
# permissions to do that much using Python's equivalent of the
# Windows API FindFirstFile.
# Other Windows APIs can fail or give incorrect results when
# dealing with files that are pending deletion.
L = os.listdir(dirname)
if not (L if waitall else name in L):
# Increase the timeout and try again
timeout *= 2
warnings.warn('tests may fail, delete still pending for ' + pathname,
RuntimeWarning, stacklevel=4)
def _unlink(filename):
_waitfor(os.unlink, filename)
def _rmdir(dirname):
_waitfor(os.rmdir, dirname)
def _rmtree(path):
def _rmtree_inner(path):
for name in os.listdir(path):
fullname = os.path.join(path, name)
mode = os.lstat(fullname).st_mode
except OSError as exc:
print("support.rmtree(): os.lstat(%r) failed with %s" % (fullname, exc),
mode = 0
if stat.S_ISDIR(mode):
_waitfor(_rmtree_inner, fullname, waitall=True)
_waitfor(_rmtree_inner, path, waitall=True)
_waitfor(os.rmdir, path)
_unlink = os.unlink
_rmdir = os.rmdir
_rmtree = shutil.rmtree
def unlink(filename):
except (FileNotFoundError, NotADirectoryError):
def rmdir(dirname):
except FileNotFoundError:
def rmtree(path):
except FileNotFoundError:
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
: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 = importlib.util.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.
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(importlib.util.cache_from_source(source, debug_override=True))
unlink(importlib.util.cache_from_source(source, debug_override=False))
# Check whether a gui is actually available
def _is_gui_available():
if hasattr(_is_gui_available, 'result'):
return _is_gui_available.result
reason = None
if sys.platform.startswith('win'):
# if Python is running as a service (such as the buildbot service),
# gui interaction may be disallowed
import ctypes
import ctypes.wintypes
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()
needed = ctypes.wintypes.DWORD()
res = dll.GetUserObjectInformationW(h,
if not res:
raise ctypes.WinError()
if not bool(uof.dwFlags & WSF_VISIBLE):
reason = "gui not available (WSF_VISIBLE flag not set)"
elif sys.platform == 'darwin':
# The Aqua Tk implementations on OS X can abort the process if
# being called in an environment where a window server connection
# cannot be made, for instance when invoked by a buildbot or ssh
# process not running under the same user id as the current console
# user. To avoid that, raise an exception if the window manager
# connection is not available.
from ctypes import cdll, c_int, pointer, Structure
from ctypes.util import find_library
app_services = cdll.LoadLibrary(find_library("ApplicationServices"))
if app_services.CGMainDisplayID() == 0:
reason = "gui tests cannot run without OS X window manager"
class ProcessSerialNumber(Structure):
_fields_ = [("highLongOfPSN", c_int),
("lowLongOfPSN", c_int)]
psn = ProcessSerialNumber()
psn_p = pointer(psn)
if ( (app_services.GetCurrentProcess(psn_p) < 0) or
(app_services.SetFrontProcess(psn_p) < 0) ):
reason = "cannot run without OS X gui process"
# check on every platform whether tkinter can actually do anything
if not reason:
from tkinter import Tk
root = Tk()
except Exception as e:
err_string = str(e)
if len(err_string) > 50:
err_string = err_string[:50] + ' [...]'
reason = 'Tk unavailable due to {}: {}'.format(type(e).__name__,
_is_gui_available.reason = reason
_is_gui_available.result = not reason
return _is_gui_available.result
def is_resource_enabled(resource):
"""Test whether a resource is enabled.
Known resources are set by If not running under,
all resources are assumed enabled unless use_resources has been set.
return use_resources is None or resource in use_resources
def requires(resource, msg=None):
"""Raise ResourceDenied if the specified resource is not available."""
if resource == 'gui' and not _is_gui_available():
raise ResourceDenied(_is_gui_available.reason)
if not is_resource_enabled(resource):
if msg is None:
msg = "Use of the %r resource not enabled" % resource
raise ResourceDenied(msg)
def _requires_unix_version(sysname, min_version):
"""Decorator raising SkipTest if the OS is `sysname` and the version is less
than `min_version`.
For example, @_requires_unix_version('FreeBSD', (7, 2)) raises SkipTest if
the FreeBSD version is less than 7.2.
def decorator(func):
def wrapper(*args, **kw):
if platform.system() == sysname:
version_txt = platform.release().split('-', 1)[0]
version = tuple(map(int, version_txt.split('.')))
except ValueError:
if version < min_version:
min_version_txt = '.'.join(map(str, min_version))
raise unittest.SkipTest(
"%s version %s or higher required, not %s"
% (sysname, min_version_txt, version_txt))
return func(*args, **kw)
wrapper.min_version = min_version
return wrapper
return decorator
def requires_freebsd_version(*min_version):
"""Decorator raising SkipTest if the OS is FreeBSD and the FreeBSD version is
less than `min_version`.
For example, @requires_freebsd_version(7, 2) raises SkipTest if the FreeBSD
version is less than 7.2.
return _requires_unix_version('FreeBSD', min_version)
def requires_linux_version(*min_version):
"""Decorator raising SkipTest if the OS is Linux and the Linux version is
less than `min_version`.
For example, @requires_linux_version(2, 6, 32) raises SkipTest if the Linux
version is less than 2.6.32.
return _requires_unix_version('Linux', min_version)
def requires_mac_ver(*min_version):
"""Decorator raising SkipTest if the OS is Mac OS X and the OS X
version if less than min_version.
For example, @requires_mac_ver(10, 5) raises SkipTest if the OS X version
is lesser than 10.5.
def decorator(func):
def wrapper(*args, **kw):
if sys.platform == 'darwin':
version_txt = platform.mac_ver()[0]
version = tuple(map(int, version_txt.split('.')))
except ValueError:
if version < min_version:
min_version_txt = '.'.join(map(str, min_version))
raise unittest.SkipTest(
"Mac OS X %s or higher required, not %s"
% (min_version_txt, version_txt))
return func(*args, **kw)
wrapper.min_version = min_version
return wrapper
return decorator
# Don't use "localhost", since resolving it uses the DNS under recent
# Windows versions (see issue #18792).
HOST = ""
HOSTv6 = "::1"
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 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
OSError 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 for more info. The following site also
has a very thorough description about the implications of both REUSEADDR
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)
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
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 == 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!")
except OSError:
# Python's socket module was compiled using modern headers
# thus defining SO_REUSEPORT but this process is running
# under an older kernel that does not support SO_REUSEPORT.
if hasattr(socket, 'SO_EXCLUSIVEADDRUSE'):
sock.setsockopt(socket.SOL_SOCKET, socket.SO_EXCLUSIVEADDRUSE, 1)
sock.bind((host, 0))
port = sock.getsockname()[1]
return port
def _is_ipv6_enabled():
"""Check whether IPv6 is enabled on this host."""
if socket.has_ipv6:
sock = None
sock = socket.socket(socket.AF_INET6, socket.SOCK_STREAM)
sock.bind((HOSTv6, 0))
return True
except OSError:
if sock:
return False
IPV6_ENABLED = _is_ipv6_enabled()
def system_must_validate_cert(f):
"""Skip the test on TLS certificate validation failures."""
def dec(*args, **kwargs):
f(*args, **kwargs)
except IOError as e:
raise unittest.SkipTest("system does not contain "
"necessary certificates")
return dec
# A constant likely larger than the underlying OS pipe buffer size, to
# make writes blocking.
# Windows limit seems to be around 512 B, and many Unix kernels have a
# 64 KiB pipe buffer size or 16 * PAGE_SIZE: take a few megs to be sure.
# (see issue #17835 for a discussion of this number).
PIPE_MAX_SIZE = 4 * 1024 * 1024 + 1
# A constant likely larger than the underlying OS socket buffer size, to make
# writes blocking.
# The socket buffer sizes can usually be tuned system-wide (e.g. through sysctl
# on Linux), or on a per-socket basis (SO_SNDBUF/SO_RCVBUF). See issue #18643
# for a discussion of this number).
SOCK_MAX_SIZE = 16 * 1024 * 1024 + 1
# decorator for skipping tests on non-IEEE 754 platforms
requires_IEEE_754 = unittest.skipUnless(
"test requires IEEE 754 doubles")
requires_zlib = unittest.skipUnless(zlib, 'requires zlib')
requires_gzip = unittest.skipUnless(gzip, 'requires gzip')
requires_bz2 = unittest.skipUnless(bz2, 'requires bz2')
requires_lzma = unittest.skipUnless(lzma, 'requires lzma')
is_jython = sys.platform.startswith('java')
# Filename used for testing
if == 'java':
# Jython disallows @ in module names
TESTFN = '$test'
TESTFN = '@test'
# Disambiguate TESTFN for parallel testing, while letting it remain a valid
# module name.
TESTFN = "{}_{}_tmp".format(TESTFN, os.getpid())
# FS_NONASCII: non-ASCII character encodable by os.fsencode(),
# or None if there is no such character.
for character in (
# First try printable and common characters to have a readable filename.
# For each character, the encoding list are just example of encodings able
# to encode the character (the list is not exhaustive).
# U+00E6 (Latin Small Letter Ae): cp1252, iso-8859-1
# U+0130 (Latin Capital Letter I With Dot Above): cp1254, iso8859_3
# U+0141 (Latin Capital Letter L With Stroke): cp1250, cp1257
# U+03C6 (Greek Small Letter Phi): cp1253
# U+041A (Cyrillic Capital Letter Ka): cp1251
# U+05D0 (Hebrew Letter Alef): Encodable to cp424
# U+060C (Arabic Comma): cp864, cp1006, iso8859_6, mac_arabic
# U+062A (Arabic Letter Teh): cp720
# U+0E01 (Thai Character Ko Kai): cp874
# Then try more "special" characters. "special" because they may be
# interpreted or displayed differently depending on the exact locale
# encoding and the font.
# U+00A0 (No-Break Space)
# U+20AC (Euro Sign)
except UnicodeError:
FS_NONASCII = character
# 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:
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.
if 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"
except UnicodeEncodeError:
print('WARNING: The filename %r CAN be encoded by the filesystem encoding (%s). '
'Unicode filename tests may not be effective'
# Mac OS X denies unencodable filenames (invalid utf-8)
elif sys.platform != 'darwin':
# ascii and utf-8 cannot encode the byte 0xff
except UnicodeDecodeError:
# 0xff will be encoded using the surrogate character u+DCFF
+ b'-\xff'.decode(TESTFN_ENCODING, 'surrogateescape')
# File system encoding (eg. ISO-8859-* encodings) can encode
# the byte 0xff. Skip some unicode filename tests.
# TESTFN_UNDECODABLE is a filename (bytes type) that should *not* be able to be
# decoded from the filesystem encoding (in strict mode). It can be None if we
# cannot generate such filename (ex: the latin1 encoding can decode any byte
# sequence). On UNIX, TESTFN_UNDECODABLE can be decoded by os.fsdecode() thanks
# to the surrogateescape error handler (PEP 383), but not from the filesystem
# encoding in strict mode.
for name in (
# b'\xff' is not decodable by os.fsdecode() with code page 932. Windows
# accepts it to create a file or a directory, or don't accept to enter to
# such directory (when the bytes name is used). So test b'\xe7' first: it is
# not decodable from cp932.
# undecodable from ASCII, UTF-8
# undecodable from iso8859-3, iso8859-6, iso8859-7, cp424, iso8859-8, cp856
# and cp857
# undecodable from UTF-8 (UNIX and Mac OS X)
b'\xed\xb2\x80', b'\xed\xb4\x80',
# undecodable from shift_jis, cp869, cp874, cp932, cp1250, cp1251, cp1252,
# cp1253, cp1254, cp1255, cp1257, cp1258
except UnicodeDecodeError:
TESTFN_UNDECODABLE = os.fsencode(TESTFN) + name
# Save the initial cwd
SAVEDCWD = os.getcwd()
def temp_dir(path=None, quiet=False):
"""Return a context manager that creates a temporary directory.
path: the directory to create temporarily. If omitted or None,
defaults to creating a temporary directory using tempfile.mkdtemp.
quiet: if False (the default), the context manager raises an exception
on error. Otherwise, if the path is specified and cannot be
created, only a warning is issued.
dir_created = False
if path is None:
path = tempfile.mkdtemp()
dir_created = True
path = os.path.realpath(path)
dir_created = True
except OSError:
if not quiet:
warnings.warn('tests may fail, unable to create temp dir: ' + path,
RuntimeWarning, stacklevel=3)
yield path
if dir_created:
def change_cwd(path, quiet=False):
"""Return a context manager that changes the current working directory.
path: the directory to use as the temporary current working directory.
quiet: if False (the default), the context manager raises an exception
on error. Otherwise, it issues only a warning and keeps the current
working directory the same.
saved_dir = os.getcwd()
except OSError:
if not quiet:
warnings.warn('tests may fail, unable to change CWD to: ' + path,
RuntimeWarning, stacklevel=3)
yield os.getcwd()
def temp_cwd(name='tempcwd', quiet=False):
Context manager that temporarily creates and changes the CWD.
The function temporarily changes the current working directory
after creating a temporary directory in the current directory with
name *name*. If *name* is None, the temporary directory is
created using tempfile.mkdtemp.
If *quiet* is False (default) and it is not possible to
create or change the CWD, an error is raised. If *quiet* is True,
only a warning is raised and the original CWD is used.
with temp_dir(path=name, quiet=quiet) as temp_path:
with change_cwd(temp_path, quiet=quiet) as cwd_dir:
yield cwd_dir
if hasattr(os, "umask"):
def temp_umask(umask):
"""Context manager that temporarily sets the process umask."""
oldmask = os.umask(umask)
# TEST_HOME_DIR refers to the top level directory of the "test" package
# that contains Python's regression test suite
TEST_SUPPORT_DIR = os.path.dirname(os.path.abspath(__file__))
# TEST_DATA_DIR is used as a target download location for remote resources
TEST_DATA_DIR = os.path.join(TEST_HOME_DIR, "data")
def findfile(filename, subdir=None):
"""Try to find a file on sys.path or in the test 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).
Setting *subdir* indicates a relative path to use to find the file
rather than looking directly in the path directories.
if os.path.isabs(filename):
return filename
if subdir is not None:
filename = os.path.join(subdir, filename)
path = [TEST_HOME_DIR] + sys.path
for dn in path:
fn = os.path.join(dn, filename)
if os.path.exists(fn): return fn
return filename
def create_empty_file(filename):
"""Create an empty file. If the file already exists, truncate it."""
fd =, os.O_WRONLY | os.O_CREAT | os.O_TRUNC)
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")
return file.fileno()
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(TEST_DATA_DIR, filename)
def check_valid_file(fn):
f = open(fn, *args, **kw)
if check is None:
return f
elif check(f):
return f
if os.path.exists(fn):
f = check_valid_file(fn)
if f is not None:
return f
# Verify the requirement before downloading the file
print('\tfetching %s ...' % url, file=get_original_stdout())
opener = urllib.request.build_opener()
if gzip:
opener.addheaders.append(('Accept-Encoding', 'gzip'))
f =, timeout=15)
if gzip and f.headers.get('Content-Encoding') == 'gzip':
f = gzip.GzipFile(fileobj=f)
with open(fn, "wb") as out:
s =
while s:
s =
f = check_valid_file(fn)
if f is not None:
return f
raise TestFailed('invalid resource %r' % 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))
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:
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.
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
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" %
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):
class EnvironmentVarGuard(
"""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]
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
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):
if getattr(value, attr) != attr_value:
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(OSError, errno=errno.ETIMEDOUT)
socket_peer_reset = TransientResource(OSError, errno=errno.ECONNRESET)
ioerror_peer_reset = TransientResource(OSError, errno=errno.ECONNRESET)
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 = [
('ECONNRESET', 104),
('ETIMEDOUT', 110),
default_gai_errnos = [
('EAI_AGAIN', -3),
('EAI_FAIL', -4),
('EAI_NONAME', -2),
('EAI_NODATA', -5),
# Encountered when trying to resolve IPv6-only hostnames
('WSANO_DATA', 11004),
denied = ResourceDenied("Resource %r 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
(isinstance(err, urllib.error.HTTPError) and
500 <= err.code <= 599) or
(isinstance(err, urllib.error.URLError) and
(("ConnectionRefusedError" in err.reason) or
("TimeoutError" in err.reason))) or
n in captured_errnos):
if not verbose:
sys.stderr.write(denied.args[0] + "\n")
raise denied from err
old_timeout = socket.getdefaulttimeout()
if timeout is not None:
except nntplib.NNTPTemporaryError as err:
if verbose:
sys.stderr.write(denied.args[0] + "\n")
raise denied from err
except OSError 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], OSError):
err = a[0]
# The error can also be wrapped as args[1]:
# except socket.error as msg:
# raise OSError('socket error', msg).with_traceback(sys.exc_info()[2])
elif len(a) >= 2 and isinstance(a[1], OSError):
err = a[1]
# XXX should we catch generic exceptions and look for their
# __cause__ or __context__?
def captured_output(stream_name):
"""Return a context manager used by captured_stdout/stdin/stderr
that temporarily replaces the sys stream *stream_name* with a StringIO."""
import io
orig_stdout = getattr(sys, stream_name)
setattr(sys, stream_name, io.StringIO())
yield getattr(sys, stream_name)
setattr(sys, stream_name, orig_stdout)
def captured_stdout():
"""Capture the output of sys.stdout:
with captured_stdout() as stdout:
self.assertEqual(stdout.getvalue(), "hello\\n")
return captured_output("stdout")
def captured_stderr():
"""Capture the output of sys.stderr:
with captured_stderr() as stderr:
print("hello", file=sys.stderr)
self.assertEqual(stderr.getvalue(), "hello\\n")
return captured_output("stderr")
def captured_stdin():
"""Capture the input to sys.stdin:
with captured_stdin() as stdin:
# call test code that consumes from sys.stdin
captured = input()
self.assertEqual(captured, "hello")
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.
if is_jython:
def disable_gc():
have_gc = gc.isenabled()
if have_gc:
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 not in ('', '-O0', '-Og')
_header = 'nP'
_align = '0n'
if hasattr(sys, "gettotalrefcount"):
_header = '2P' + _header
_align = '0P'
_vheader = _header + 'n'
def calcobjsize(fmt):
return struct.calcsize(_header + fmt + _align)
def calcvobjsize(fmt):
return struct.calcsize(_vheader + fmt + _align)
def check_sizeof(test, o, size):
import _testcapi
result = sys.getsizeof(o)
# add GC header size
if ((type(o) == type) and (o.__flags__ & _TPFLAGS_HEAPTYPE) or\
((type(o) != type) and (type(o).__flags__ & _TPFLAGS_HAVE_GC))):
size += _testcapi.SIZEOF_PYGC_HEAD
msg = 'wrong size for %s: got %d, expected %d' \
% (type(o), result, size)
test.assertEqual(result, size, msg)
# 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):
import locale
category = getattr(locale, catstr)
orig_locale = locale.setlocale(category)
except AttributeError:
# if the test author gives us an invalid category string
# cannot retrieve original locale, so do nothing
locale = orig_locale = None
for loc in locales:
locale.setlocale(category, loc)
# now run the function, resetting the locale on exceptions
return func(*args, **kwds)
if locale and orig_locale:
locale.setlocale(category, orig_locale)
inner.__name__ = func.__name__
inner.__doc__ = func.__doc__
return inner
return decorator
# Decorator for running a function in a specific timezone, correctly
# resetting it afterwards.
def run_with_tz(tz):
def decorator(func):
def inner(*args, **kwds):
tzset = time.tzset
except AttributeError:
raise unittest.SkipTest("tzset required")
if 'TZ' in os.environ:
orig_tz = os.environ['TZ']
orig_tz = None
os.environ['TZ'] = tz
# now run the function, resetting the tz on exceptions
return func(*args, **kwds)
if orig_tz is None:
del os.environ['TZ']
os.environ['TZ'] = orig_tz
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,
if m is None:
raise ValueError('Invalid memory limit %r' % (limit,))
memlimit = int(float( * sizes[])
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
class _MemoryWatchdog:
"""An object which periodically watches the process' memory consumption
and prints it out.
def __init__(self):
self.procfile = '/proc/{pid}/statm'.format(pid=os.getpid())
self.started = False
def start(self):
f = open(self.procfile, 'r')
except OSError as e:
warnings.warn('/proc not available for stats: {}'.format(e),
watchdog_script = findfile("")
self.mem_watchdog = subprocess.Popen([sys.executable, watchdog_script],
stdin=f, stderr=subprocess.DEVNULL)
self.started = True
def stop(self):
if self.started:
def bigmemtest(size, memuse, dry_run=True):
"""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.
if 'dry_run' is False, it means the test doesn't support dummy runs
when -M is not specified.
def decorator(f):
def wrapper(self):
size = wrapper.size
memuse = wrapper.memuse
if not real_max_memuse:
maxsize = 5147
maxsize = size
if ((real_max_memuse or not dry_run)
and real_max_memuse < maxsize * memuse):
raise unittest.SkipTest(
"not enough memory: %.1fG minimum needed"
% (size * memuse / (1024 ** 3)))
if real_max_memuse and verbose:
print(" ... expected peak memory use: {peak:.1f}G"
.format(peak=size * memuse / (1024 ** 3)))
watchdog = _MemoryWatchdog()
watchdog = None
return f(self, maxsize)
if watchdog:
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")
raise unittest.SkipTest(
"not enough memory: %.1fG minimum needed"
% (MAX_Py_ssize_t / (1024 ** 3)))
return f(self)
return wrapper
# unittest integration.
class BasicTestRunner:
def run(self, test):
result = unittest.TestResult()
return result
def _id(obj):
return obj
def requires_resource(resource):
if resource == 'gui' and not _is_gui_available():
return unittest.skip(_is_gui_available.reason)
if is_resource_enabled(resource):
return _id
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}"
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.
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
def wrapper(*args, **kwargs):
original_trace = sys.gettrace()
return func(*args, **kwargs)
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 _filter_suite(suite, pred):
"""Recursively filter test cases in a suite based on a predicate."""
newtests = []
for test in suite._tests:
if isinstance(test, unittest.TestSuite):
_filter_suite(test, pred)
if pred(test):
suite._tests = newtests
def _run_suite(suite):
"""Run tests from a unittest.TestSuite-derived class."""
if verbose:
runner = unittest.TextTestRunner(sys.stdout, verbosity=2,
runner = BasicTestRunner()
result =
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]
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:
raise ValueError("str arguments must be keys in sys.modules")
elif isinstance(cls, valid_types):
def case_pred(test):
if match_tests is None:
return True
for name in"."):
if fnmatch.fnmatchcase(name, match_tests):
return True
return False
_filter_suite(suite, case_pred)
# Check for the presence of docstrings.
# Rather than trying to enumerate all the cases where docstrings may be
# disabled, we just check for that directly
def _check_docstrings():
"""Just used to check if docstrings are enabled"""
MISSING_C_DOCSTRINGS = (check_impl_detail() and
sys.platform != 'win32' and
not sysconfig.get_config_var('WITH_DOC_STRINGS'))
HAVE_DOCSTRINGS = (_check_docstrings.__doc__ is not None and
requires_docstrings = unittest.skipUnless(HAVE_DOCSTRINGS,
"test requires docstrings")
# doctest driver.
def run_doctest(module, verbosity=None, optionflags=0):
"""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
verbosity = None
f, t = doctest.testmod(module, verbose=verbosity, optionflags=optionflags)
if f:
raise TestFailed("%d of %d doctests failed" % (f, t))
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.')]
# 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).
# Threading support to prevent reporting refleaks when running -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(), threading._dangling.copy()
return 1, ()
def threading_cleanup(*original_values):
if not _thread:
_MAX_COUNT = 100
for count in range(_MAX_COUNT):
values = _thread._count(), threading._dangling
if values == original_values:
# 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
def decorator(*args):
key = threading_setup()
return func(*args)
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:
# This will raise an exception on Windows. That's ok.
pid, status = os.waitpid(any_process, os.WNOHANG)
if pid == 0:
def start_threads(threads, unlock=None):
threads = list(threads)
started = []
for t in threads:
if verbose:
print("Can't start %d threads, only %d threads started" %
(len(threads), len(started)))
if unlock:
endtime = starttime = time.time()
for timeout in range(1, 16):
endtime += 60
for t in started:
t.join(max(endtime - time.time(), 0.01))
started = [t for t in started if t.isAlive()]
if not started:
if verbose:
print('Unable to join %d threads during a period of '
'%d minutes' % (len(started), timeout))
started = [t for t in started if t.isAlive()]
if started:
raise AssertionError('Unable to join %d threads' % len(started))
def swap_attr(obj, attr, new_val):
"""Temporary swap out an attribute with a new object.
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
if hasattr(obj, attr):
real_val = getattr(obj, attr)
setattr(obj, attr, new_val)
setattr(obj, attr, real_val)
setattr(obj, attr, new_val)
delattr(obj, attr)
def swap_item(obj, item, new_val):
"""Temporary swap out an item with a new object.
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
if item in obj:
real_val = obj[item]
obj[item] = new_val
obj[item] = real_val
obj[item] = new_val
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"\[\d+ refs, \d+ blocks\]\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 and sys.warnoptions."""
return subprocess._args_from_interpreter_flags()
# 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):
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
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
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)
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
symlink_path = TESTFN + "can_symlink"
os.symlink(TESTFN, symlink_path)
can = True
except (OSError, NotImplementedError, AttributeError):
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)
_can_xattr = None
def can_xattr():
global _can_xattr
if _can_xattr is not None:
return _can_xattr
if not hasattr(os, "setxattr"):
can = False
tmp_fp, tmp_name = tempfile.mkstemp()
with open(TESTFN, "wb") as fp:
# TESTFN & tempfile may use different file systems with
# different capabilities
os.setxattr(tmp_fp, b"user.test", b"")
os.setxattr(fp.fileno(), b"user.test", b"")
# Kernels < 2.6.39 don't respect setxattr flags.
kernel_version = platform.release()
m = re.match("2.6.(\d{1,2})", kernel_version)
can = m is None or int( >= 39
except OSError:
can = False
_can_xattr = can
return can
def skip_unless_xattr(test):
"""Skip decorator for tests that require functional extended attributes"""
ok = can_xattr()
msg = "no non-broken extended attribute support"
return test if ok else unittest.skip(msg)(test)
def fs_is_case_insensitive(directory):
"""Detects if the file system for the specified directory is case-insensitive."""
with tempfile.NamedTemporaryFile(dir=directory) as base:
base_path =
case_path = base_path.upper()
if case_path == base_path:
case_path = base_path.lower()
return os.path.samefile(base_path, case_path)
except FileNotFoundError:
return False
class SuppressCrashReport:
"""Try to prevent a crash report from popping up.
On Windows, don't display the Windows Error Reporting dialog. On UNIX,
disable the creation of coredump file.
old_value = None
def __enter__(self):
"""On Windows, disable Windows Error Reporting dialogs using
On UNIX, try to save the previous core file size limit, then set
soft limit to 0.
if sys.platform.startswith('win'):
# see
# GetErrorMode is not available on Windows XP and Windows Server 2003,
# but SetErrorMode returns the previous value, so we can use that
import ctypes
self._k32 = ctypes.windll.kernel32
self.old_value = self._k32.SetErrorMode(SEM_NOGPFAULTERRORBOX)
self._k32.SetErrorMode(self.old_value | SEM_NOGPFAULTERRORBOX)
if resource is not None:
self.old_value = resource.getrlimit(resource.RLIMIT_CORE)
(0, self.old_value[1]))
except (ValueError, OSError):
if sys.platform == 'darwin':
# Check if the 'Crash Reporter' on OSX was configured
# in 'Developer' mode and warn that it will get triggered
# when it is.
# This assumes that this context manager is used in tests
# that might trigger the next manager.
value = subprocess.Popen(['/usr/bin/defaults', 'read',
'', 'DialogType'],
if value.strip() == b'developer':
print("this test triggers the Crash Reporter, "
"that is intentional", end='', flush=True)
return self
def __exit__(self, *ignore_exc):
"""Restore Windows ErrorMode or core file behavior to initial value."""
if self.old_value is None:
if sys.platform.startswith('win'):
if resource is not None:
resource.setrlimit(resource.RLIMIT_CORE, self.old_value)
except (ValueError, OSError):
def patch(test_instance, object_to_patch, attr_name, new_value):
"""Override 'object_to_patch'.'attr_name' with 'new_value'.
Also, add a cleanup procedure to 'test_instance' to restore
'object_to_patch' value for 'attr_name'.
The 'attr_name' should be a valid attribute for 'object_to_patch'.
# check that 'attr_name' is a real attribute for 'object_to_patch'
# will raise AttributeError if it does not exist
getattr(object_to_patch, attr_name)
# keep a copy of the old value
attr_is_local = False
old_value = object_to_patch.__dict__[attr_name]
except (AttributeError, KeyError):
old_value = getattr(object_to_patch, attr_name, None)
attr_is_local = True
# restore the value when the test is done
def cleanup():
if attr_is_local:
setattr(object_to_patch, attr_name, old_value)
delattr(object_to_patch, attr_name)
# actually override the attribute
setattr(object_to_patch, attr_name, new_value)
def run_in_subinterp(code):
Run code in a subinterpreter. Raise unittest.SkipTest if the tracemalloc
module is enabled.
# Issue #10915, #15751: PyGILState_*() functions don't work with
# sub-interpreters, the tracemalloc module uses these functions internally
import tracemalloc
except ImportError:
if tracemalloc.is_tracing():
raise unittest.SkipTest("run_in_subinterp() cannot be used "
"if tracemalloc module is tracing "
"memory allocations")
import _testcapi
return _testcapi.run_in_subinterp(code)
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