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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 socket
import sys
import os
import os.path
import shutil
import warnings
import unittest
__all__ = ["Error", "TestFailed", "TestSkipped", "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",
"fcmp", "is_jython", "TESTFN", "HOST", "FUZZ", "findfile", "verify",
"vereq", "sortdict", "check_syntax_error", "open_urlresource",
"WarningMessage", "catch_warning", "CleanImport", "EnvironmentVarGuard",
"TransientResource", "captured_output", "captured_stdout",
"TransientResource", "transient_internet", "run_with_locale",
"set_memlimit", "bigmemtest", "bigaddrspacetest", "BasicTestRunner",
"run_unittest", "run_doctest", "threading_setup", "threading_cleanup",
"reap_children"]
class Error(Exception):
"""Base class for regression test exceptions."""
class TestFailed(Error):
"""Test failed."""
class TestSkipped(Error):
"""Test skipped.
This can be raised to indicate that a test was deliberatly
skipped, but not because a feature wasn't available. For
example, if some resource can't be used, such as the network
appears to be unavailable, this should be raised instead of
TestFailed.
"""
class ResourceDenied(TestSkipped):
"""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 import_module(name, deprecated=False):
"""Import the module to be tested, raising TestSkipped if it is not
available."""
with catch_warning(record=False):
if deprecated:
warnings.filterwarnings("ignore", ".+ (module|package)",
DeprecationWarning)
try:
module = __import__(name, level=0)
except ImportError:
raise TestSkipped("No module named " + name)
else:
return module
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.)
# _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:
pass
def rmtree(path):
try:
shutil.rmtree(path)
except OSError as e:
# Unix returns ENOENT, Windows returns ESRCH.
if e.errno not in (errno.ENOENT, errno.ESRCH):
raise
def forget(modname):
'''"Forget" a module was ever imported by removing it from sys.modules and
deleting any .pyc and .pyo files.'''
unload(modname)
for dirname in sys.path:
unlink(os.path.join(dirname, modname + '.pyc'))
# Deleting the .pyo file cannot be within the 'try' for the .pyc since
# the chance exists that there is no .pyc (and thus the 'try' statement
# is exited) but there is a .pyo file.
unlink(os.path.join(dirname, modname + '.pyo'))
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."""
# see if the caller's module is __main__ - if so, treat as if
# the resource was set
if sys._getframe().f_back.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
FUZZ = 1e-6
def fcmp(x, y): # fuzzy comparison function
if isinstance(x, float) or isinstance(y, float):
try:
fuzz = (abs(x) + abs(y)) * FUZZ
if abs(x-y) <= fuzz:
return 0
except:
pass
elif type(x) == type(y) and isinstance(x, (tuple, list)):
for i in range(min(len(x), len(y))):
outcome = fcmp(x[i], y[i])
if outcome != 0:
return outcome
return (len(x) > len(y)) - (len(x) < len(y))
return (x > y) - (x < y)
is_jython = sys.platform.startswith('java')
# Filename used for testing
if os.name == 'java':
# Jython disallows @ in module names
TESTFN = '$test'
else:
TESTFN = '@test'
# Assuming sys.getfilesystemencoding()!=sys.getdefaultencoding()
# TESTFN_UNICODE is a filename that can be encoded using the
# file system encoding, but *not* with the default (ascii) encoding
TESTFN_UNICODE = "@test-\xe0\xf2"
TESTFN_ENCODING = sys.getfilesystemencoding()
# TESTFN_UNICODE_UNENCODEABLE is a filename that should *not* be
# able to be encoded by *either* the default or filesystem encoding.
# This test really only makes sense on Windows NT platforms
# which have special Unicode support in posixmodule.
if (not hasattr(sys, "getwindowsversion") or
sys.getwindowsversion()[3] < 2): # 0=win32s or 1=9x/ME
TESTFN_UNICODE_UNENCODEABLE = None
else:
# Japanese characters (I think - from bug 846133)
TESTFN_UNICODE_UNENCODEABLE = "@test-\u5171\u6709\u3055\u308c\u308b"
try:
# XXX - Note - should be using TESTFN_ENCODING here - but for
# Windows, "mbcs" currently always operates as if in
# errors=ignore' mode - hence we get '?' characters rather than
# the exception. 'Latin1' operates as we expect - ie, fails.
# See [ 850997 ] mbcs encoding ignores errors
TESTFN_UNICODE_UNENCODEABLE.encode("Latin1")
except UnicodeEncodeError:
pass
else:
print('WARNING: The filename %r CAN be encoded by the filesystem. '
'Unicode filename tests may not be effective'
% TESTFN_UNICODE_UNENCODEABLE)
# Make sure we can write to TESTFN, try in /tmp if we can't
fp = None
try:
fp = open(TESTFN, 'w+')
except IOError:
TMP_TESTFN = os.path.join('/tmp', TESTFN)
try:
fp = open(TMP_TESTFN, 'w+')
TESTFN = TMP_TESTFN
del TMP_TESTFN
except IOError:
print(('WARNING: tests will fail, unable to write to: %s or %s' %
(TESTFN, TMP_TESTFN)))
if fp is not None:
fp.close()
unlink(TESTFN)
del fp
def findfile(file, here=__file__):
"""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
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 verify(condition, reason='test failed'):
"""Verify that condition is true. If not, raise TestFailed.
The optional argument reason can be given to provide
a better error text.
"""
if not condition:
raise TestFailed(reason)
def vereq(a, b):
"""Raise TestFailed if a == b is false.
This is better than verify(a == b) because, in case of failure, the
error message incorporates repr(a) and repr(b) so you can see the
inputs.
Note that "not (a == b)" isn't necessarily the same as "a != b"; the
former is tested.
"""
if not (a == b):
raise TestFailed("%r == %r" % (a, b))
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 check_syntax_error(testcase, statement):
try:
compile(statement, '<test string>', 'exec')
except SyntaxError:
pass
else:
testcase.fail('Missing SyntaxError: "%s"' % statement)
def open_urlresource(url, *args, **kw):
import urllib, urlparse
requires('urlfetch')
filename = urlparse.urlparse(url)[2].split('/')[-1] # '/': it's URL!
for path in [os.path.curdir, os.path.pardir]:
fn = os.path.join(path, filename)
if os.path.exists(fn):
return open(fn, *args, **kw)
print('\tfetching %s ...' % url, file=get_original_stdout())
fn, _ = urllib.urlretrieve(url, filename)
return open(fn, *args, **kw)
class WarningMessage(object):
"Holds the result of the latest showwarning() call"
def __init__(self):
self.message = None
self.category = None
self.filename = None
self.lineno = None
def _showwarning(self, message, category, filename, lineno, file=None,
line=None):
self.message = message
self.category = category
self.filename = filename
self.lineno = lineno
self.line = line
def reset(self):
self._showwarning(*((None,)*6))
def __str__(self):
return ("{message : %r, category : %r, filename : %r, lineno : %s, "
"line : %r}" % (self.message,
self.category.__name__ if self.category else None,
self.filename, self.lineno, self.line))
@contextlib.contextmanager
def catch_warning(module=warnings, record=True):
"""
Guard the warnings filter from being permanently changed and record the
data of the last warning that has been issued.
Use like this:
with catch_warning() as w:
warnings.warn("foo")
assert str(w.message) == "foo"
"""
original_filters = module.filters[:]
original_showwarning = module.showwarning
if record:
warning_obj = WarningMessage()
module.showwarning = warning_obj._showwarning
try:
yield warning_obj if record else None
finally:
module.showwarning = original_showwarning
module.filters = original_filters
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 DepreciationWarning on import.
Use like this:
with CleanImport("foo"):
__import__("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(object):
"""Class to help protect the environment variable properly. Can be used as
a context manager."""
def __init__(self):
self._environ = os.environ
self._unset = set()
self._reset = dict()
def set(self, envvar, value):
if envvar not in self._environ:
self._unset.add(envvar)
else:
self._reset[envvar] = self._environ[envvar]
self._environ[envvar] = value
def unset(self, envvar):
if envvar in self._environ:
self._reset[envvar] = self._environ[envvar]
del self._environ[envvar]
def __enter__(self):
return self
def __exit__(self, *ignore_exc):
for envvar, value in self._reset.items():
self._environ[envvar] = value
for unset in self._unset:
del self._environ[unset]
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")
def transient_internet():
"""Return a context manager that raises ResourceDenied when various issues
with the Internet connection manifest themselves as exceptions."""
time_out = TransientResource(IOError, errno=errno.ETIMEDOUT)
socket_peer_reset = TransientResource(socket.error, errno=errno.ECONNRESET)
ioerror_peer_reset = TransientResource(IOError, errno=errno.ECONNRESET)
return contextlib.nested(time_out, socket_peer_reset, ioerror_peer_reset)
@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")
#=======================================================================
# 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
MAX_Py_ssize_t = sys.maxsize
def set_memlimit(limit):
import re
global 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()])
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, overhead=5*_1M):
"""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. 'overhead' specifies fixed overhead,
independent of the testsize, and defaults to 5Mb.
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):
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.failIf(maxsize * memuse + overhead > 20 * _1M)
else:
maxsize = int((max_memuse - overhead) / memuse)
if maxsize < minsize:
# Really ought to print 'test skipped' or something
if verbose:
sys.stderr.write("Skipping %s because of memory "
"constraint\n" % (f.__name__,))
return
# Try to keep some breathing room in memory use
maxsize = max(maxsize - 50 * _1M, minsize)
return f(self, maxsize)
wrapper.minsize = minsize
wrapper.memuse = memuse
wrapper.overhead = overhead
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 verbose:
sys.stderr.write("Skipping %s because of memory "
"constraint\n" % (f.__name__,))
else:
return f(self)
return wrapper
#=======================================================================
# unittest integration.
class BasicTestRunner:
def run(self, test):
result = unittest.TestResult()
test(result)
return result
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 = "errors occurred; 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
#=======================================================================
# Threading support to prevent reporting refleaks when running regrtest.py -R
def threading_setup():
import threading
return len(threading._active), len(threading._limbo)
def threading_cleanup(num_active, num_limbo):
import threading
import time
_MAX_COUNT = 10
count = 0
while len(threading._active) != num_active and count < _MAX_COUNT:
count += 1
time.sleep(0.1)
count = 0
while len(threading._limbo) != num_limbo and count < _MAX_COUNT:
count += 1
time.sleep(0.1)
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
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