"""Supporting definitions for the Python regression tests.""" if __name__ != 'test.support': raise ImportError('support must be imported from the test package') import contextlib import functools import os import re import stat import sys import sysconfig import time import types import unittest from .import_helper import ( CleanImport, DirsOnSysPath, _ignore_deprecated_imports, _save_and_block_module, _save_and_remove_module, forget, import_fresh_module, import_module, make_legacy_pyc, modules_cleanup, modules_setup, unload) from .os_helper import ( FS_NONASCII, SAVEDCWD, TESTFN, TESTFN_ASCII, TESTFN_NONASCII, TESTFN_UNENCODABLE, TESTFN_UNDECODABLE, TESTFN_UNICODE, can_symlink, can_xattr, change_cwd, create_empty_file, fd_count, fs_is_case_insensitive, make_bad_fd, rmdir, rmtree, skip_unless_symlink, skip_unless_xattr, temp_cwd, temp_dir, temp_umask, unlink, EnvironmentVarGuard, FakePath, _longpath) from .warnings_helper import ( WarningsRecorder, _filterwarnings, check_no_resource_warning, check_no_warnings, check_syntax_warning, check_warnings, ignore_warnings) from .testresult import get_test_runner __all__ = [ # globals "PIPE_MAX_SIZE", "verbose", "max_memuse", "use_resources", "failfast", # exceptions "Error", "TestFailed", "TestDidNotRun", "ResourceDenied", # io "record_original_stdout", "get_original_stdout", "captured_stdout", "captured_stdin", "captured_stderr", # unittest "is_resource_enabled", "requires", "requires_freebsd_version", "requires_linux_version", "requires_mac_ver", "check_syntax_error", "BasicTestRunner", "run_unittest", "run_doctest", "requires_gzip", "requires_bz2", "requires_lzma", "bigmemtest", "bigaddrspacetest", "cpython_only", "get_attribute", "requires_IEEE_754", "requires_zlib", "anticipate_failure", "load_package_tests", "detect_api_mismatch", "check__all__", "skip_if_buggy_ucrt_strfptime", # sys "is_jython", "is_android", "check_impl_detail", "unix_shell", "setswitchinterval", # network "open_urlresource", # processes "reap_children", # miscellaneous "run_with_locale", "swap_item", "findfile", "swap_attr", "Matcher", "set_memlimit", "SuppressCrashReport", "sortdict", "run_with_tz", "PGO", "missing_compiler_executable", "ALWAYS_EQ", "NEVER_EQ", "LARGEST", "SMALLEST", "LOOPBACK_TIMEOUT", "INTERNET_TIMEOUT", "SHORT_TIMEOUT", "LONG_TIMEOUT", ] # Timeout in seconds for tests using a network server listening on the network # local loopback interface like 127.0.0.1. # # The timeout is long enough to prevent test failure: it takes into account # that the client and the server can run in different threads or even different # processes. # # The timeout should be long enough for connect(), recv() and send() methods # of socket.socket. LOOPBACK_TIMEOUT = 5.0 if sys.platform == 'win32' and ' 32 bit (ARM)' in sys.version: # bpo-37553: test_socket.SendfileUsingSendTest is taking longer than 2 # seconds on Windows ARM32 buildbot LOOPBACK_TIMEOUT = 10 # Timeout in seconds for network requests going to the Internet. The timeout is # short enough to prevent a test to wait for too long if the Internet request # is blocked for whatever reason. # # Usually, a timeout using INTERNET_TIMEOUT should not mark a test as failed, # but skip the test instead: see transient_internet(). INTERNET_TIMEOUT = 60.0 # Timeout in seconds to mark a test as failed if the test takes "too long". # # The timeout value depends on the regrtest --timeout command line option. # # If a test using SHORT_TIMEOUT starts to fail randomly on slow buildbots, use # LONG_TIMEOUT instead. SHORT_TIMEOUT = 30.0 # Timeout in seconds to detect when a test hangs. # # It is long enough to reduce the risk of test failure on the slowest Python # buildbots. It should not be used to mark a test as failed if the test takes # "too long". The timeout value depends on the regrtest --timeout command line # option. LONG_TIMEOUT = 5 * 60.0 class Error(Exception): """Base class for regression test exceptions.""" class TestFailed(Error): """Test failed.""" class TestDidNotRun(Error): """Test did not run any subtests.""" 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 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 = loader.discover(start_dir=pkg_dir, top_level_dir=top_dir, pattern=pattern) standard_tests.addTests(package_tests) return standard_tests def get_attribute(obj, name): """Get an attribute, raising SkipTest if AttributeError is raised.""" try: attribute = getattr(obj, name) except AttributeError: raise unittest.SkipTest("object %r has no attribute %r" % (obj, 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 junit_xml_list = None # list of testsuite XML elements failfast = False # _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 _force_run(path, func, *args): try: return func(*args) except OSError as err: if verbose >= 2: print('%s: %s' % (err.__class__.__name__, err)) print('re-run %s%r' % (func.__name__, args)) os.chmod(path, stat.S_IRWXU) return func(*args) # Check whether a gui is actually available def _is_gui_available(): if hasattr(_is_gui_available, 'result'): return _is_gui_available.result import platform reason = None if sys.platform.startswith('win') and platform.win32_is_iot(): reason = "gui is not available on Windows IoT Core" elif 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 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() 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" else: 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: try: from tkinter import Tk root = Tk() root.withdraw() root.update() root.destroy() 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__, err_string) _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 regrtest.py. If not running under regrtest.py, 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 not is_resource_enabled(resource): if msg is None: msg = "Use of the %r resource not enabled" % resource raise ResourceDenied(msg) if resource == 'gui' and not _is_gui_available(): raise ResourceDenied(_is_gui_available.reason) 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. """ import platform min_version_txt = '.'.join(map(str, min_version)) version_txt = platform.release().split('-', 1)[0] if platform.system() == sysname: try: version = tuple(map(int, version_txt.split('.'))) except ValueError: skip = False else: skip = version < min_version else: skip = False return unittest.skipIf( skip, f"{sysname} version {min_version_txt} or higher required, not " f"{version_txt}" ) 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): @functools.wraps(func) def wrapper(*args, **kw): if sys.platform == 'darwin': import platform version_txt = platform.mac_ver()[0] try: version = tuple(map(int, version_txt.split('.'))) except ValueError: pass else: 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 def system_must_validate_cert(f): """Skip the test on TLS certificate validation failures.""" @functools.wraps(f) def dec(*args, **kwargs): try: f(*args, **kwargs) except OSError as e: if "CERTIFICATE_VERIFY_FAILED" in str(e): raise unittest.SkipTest("system does not contain " "necessary certificates") raise 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( float.__getformat__("double").startswith("IEEE"), "test requires IEEE 754 doubles") def requires_zlib(reason='requires zlib'): try: import zlib except ImportError: zlib = None return unittest.skipUnless(zlib, reason) def requires_gzip(reason='requires gzip'): try: import gzip except ImportError: gzip = None return unittest.skipUnless(gzip, reason) def requires_bz2(reason='requires bz2'): try: import bz2 except ImportError: bz2 = None return unittest.skipUnless(bz2, reason) def requires_lzma(reason='requires lzma'): try: import lzma except ImportError: lzma = None return unittest.skipUnless(lzma, reason) is_jython = sys.platform.startswith('java') is_android = hasattr(sys, 'getandroidapilevel') if sys.platform != 'win32': unix_shell = '/system/bin/sh' if is_android else '/bin/sh' else: unix_shell = None # Define the URL of a dedicated HTTP server for the network tests. # The URL must use clear-text HTTP: no redirection to encrypted HTTPS. TEST_HTTP_URL = "http://www.pythontest.net" # Set by libregrtest/main.py so we can skip tests that are not # useful for PGO PGO = False # Set by libregrtest/main.py if we are running the extended (time consuming) # PGO task. If this is True, PGO is also True. PGO_EXTENDED = False # 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_HOME_DIR = os.path.dirname(TEST_SUPPORT_DIR) # 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 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, errtext='', *, lineno=None, offset=None): with testcase.assertRaisesRegex(SyntaxError, errtext) as cm: compile(statement, '', 'exec') err = cm.exception testcase.assertIsNotNone(err.lineno) if lineno is not None: testcase.assertEqual(err.lineno, lineno) testcase.assertIsNotNone(err.offset) if offset is not None: testcase.assertEqual(err.offset, offset) def open_urlresource(url, *args, **kw): import urllib.request, urllib.parse try: import gzip except ImportError: gzip = None 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): 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') if verbose: print('\tfetching %s ...' % url, file=get_original_stdout()) opener = urllib.request.build_opener() if gzip: opener.addheaders.append(('Accept-Encoding', 'gzip')) f = opener.open(url, timeout=INTERNET_TIMEOUT) if gzip and f.headers.get('Content-Encoding') == 'gzip': f = gzip.GzipFile(fileobj=f) 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 %r' % fn) @contextlib.contextmanager 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()) try: yield getattr(sys, stream_name) finally: setattr(sys, stream_name, orig_stdout) def captured_stdout(): """Capture the output of sys.stdout: with captured_stdout() as stdout: print("hello") 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: stdin.write('hello\\n') stdin.seek(0) # 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. """ import gc gc.collect() if is_jython: time.sleep(0.1) gc.collect() gc.collect() @contextlib.contextmanager def disable_gc(): import gc have_gc = gc.isenabled() gc.disable() try: yield finally: if have_gc: gc.enable() 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, "getobjects"): _header = '2P' + _header _align = '0P' _vheader = _header + 'n' def calcobjsize(fmt): import struct return struct.calcsize(_header + fmt + _align) def calcvobjsize(fmt): import struct return struct.calcsize(_vheader + fmt + _align) _TPFLAGS_HAVE_GC = 1<<14 _TPFLAGS_HEAPTYPE = 1<<9 def check_sizeof(test, o, size): import _testinternalcapi 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 += _testinternalcapi.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): 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 #======================================================================= # 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): try: tzset = time.tzset except AttributeError: raise unittest.SkipTest("tzset required") if 'TZ' in os.environ: orig_tz = os.environ['TZ'] else: orig_tz = None os.environ['TZ'] = tz tzset() # now run the function, resetting the tz on exceptions try: return func(*args, **kwds) finally: if orig_tz is None: del os.environ['TZ'] else: os.environ['TZ'] = orig_tz time.tzset() 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 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): import warnings try: f = open(self.procfile, 'r') except OSError as e: warnings.warn('/proc not available for stats: {}'.format(e), RuntimeWarning) sys.stderr.flush() return import subprocess with f: watchdog_script = findfile("memory_watchdog.py") self.mem_watchdog = subprocess.Popen([sys.executable, watchdog_script], stdin=f, stderr=subprocess.DEVNULL) self.started = True def stop(self): if self.started: self.mem_watchdog.terminate() self.mem_watchdog.wait() def bigmemtest(size, memuse, dry_run=True): """Decorator for bigmem tests. 'size' is a requested size for the test (in arbitrary, test-interpreted units.) 'memuse' is the number of bytes per unit for the test, or a good estimate of it. For example, a test that needs two byte buffers, of 4 GiB each, could be decorated with @bigmemtest(size=_4G, memuse=2). The 'size' argument is normally passed to the decorated test method as an extra argument. If 'dry_run' is true, the value passed to the test method may be less than the requested value. 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 else: 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() print(" ... expected peak memory use: {peak:.1f}G" .format(peak=size * memuse / (1024 ** 3))) watchdog = _MemoryWatchdog() watchdog.start() else: watchdog = None try: return f(self, maxsize) finally: if watchdog: watchdog.stop() 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(_is_gui_available.reason) 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(sys.implementation.name, 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 _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) newtests.append(test) else: if pred(test): newtests.append(test) suite._tests = newtests def _run_suite(suite): """Run tests from a unittest.TestSuite-derived class.""" runner = get_test_runner(sys.stdout, verbosity=verbose, capture_output=(junit_xml_list is not None)) result = runner.run(suite) if junit_xml_list is not None: junit_xml_list.append(result.get_xml_element()) if not result.testsRun and not result.skipped: raise TestDidNotRun 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) # By default, don't filter tests _match_test_func = None _accept_test_patterns = None _ignore_test_patterns = None def match_test(test): # Function used by support.run_unittest() and regrtest --list-cases if _match_test_func is None: return True else: return _match_test_func(test.id()) def _is_full_match_test(pattern): # If a pattern contains at least one dot, it's considered # as a full test identifier. # Example: 'test.test_os.FileTests.test_access'. # # ignore patterns which contain fnmatch patterns: '*', '?', '[...]' # or '[!...]'. For example, ignore 'test_access*'. return ('.' in pattern) and (not re.search(r'[?*\[\]]', pattern)) def set_match_tests(accept_patterns=None, ignore_patterns=None): global _match_test_func, _accept_test_patterns, _ignore_test_patterns if accept_patterns is None: accept_patterns = () if ignore_patterns is None: ignore_patterns = () accept_func = ignore_func = None if accept_patterns != _accept_test_patterns: accept_patterns, accept_func = _compile_match_function(accept_patterns) if ignore_patterns != _ignore_test_patterns: ignore_patterns, ignore_func = _compile_match_function(ignore_patterns) # Create a copy since patterns can be mutable and so modified later _accept_test_patterns = tuple(accept_patterns) _ignore_test_patterns = tuple(ignore_patterns) if accept_func is not None or ignore_func is not None: def match_function(test_id): accept = True ignore = False if accept_func: accept = accept_func(test_id) if ignore_func: ignore = ignore_func(test_id) return accept and not ignore _match_test_func = match_function def _compile_match_function(patterns): if not patterns: func = None # set_match_tests(None) behaves as set_match_tests(()) patterns = () elif all(map(_is_full_match_test, patterns)): # Simple case: all patterns are full test identifier. # The test.bisect_cmd utility only uses such full test identifiers. func = set(patterns).__contains__ else: import fnmatch regex = '|'.join(map(fnmatch.translate, patterns)) # The search *is* case sensitive on purpose: # don't use flags=re.IGNORECASE regex_match = re.compile(regex).match def match_test_regex(test_id): if regex_match(test_id): # The regex matches the whole identifier, for example # 'test.test_os.FileTests.test_access'. return True else: # Try to match parts of the test identifier. # For example, split 'test.test_os.FileTests.test_access' # into: 'test', 'test_os', 'FileTests' and 'test_access'. return any(map(regex_match, test_id.split("."))) func = match_test_regex return patterns, func 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)) _filter_suite(suite, match_test) _run_suite(suite) #======================================================================= # 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 not MISSING_C_DOCSTRINGS) 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 else: 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 print_warning(msg): # bpo-39983: Print into sys.__stderr__ to display the warning even # when sys.stderr is captured temporarily by a test for line in msg.splitlines(): print(f"Warning -- {line}", file=sys.__stderr__, flush=True) # Flag used by saved_test_environment of test.libregrtest.save_env, # to check if a test modified the environment. The flag should be set to False # before running a new test. # # For example, threading_helper.threading_cleanup() sets the flag is the function fails # to cleanup threads. environment_altered = False 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. """ global environment_altered # Need os.waitpid(-1, os.WNOHANG): Windows is not supported if not (hasattr(os, 'waitpid') and hasattr(os, 'WNOHANG')): return # 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. while True: try: # Read the exit status of any child process which already completed pid, status = os.waitpid(-1, os.WNOHANG) except OSError: break if pid == 0: break print_warning(f"reap_children() reaped child process {pid}") environment_altered = True @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. The old value (or None if it doesn't exist) will be assigned to the target of the "as" clause, if there is one. """ if hasattr(obj, attr): real_val = getattr(obj, attr) setattr(obj, attr, new_val) try: yield real_val finally: setattr(obj, attr, real_val) else: setattr(obj, attr, new_val) try: yield finally: if hasattr(obj, attr): 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. The old value (or None if it doesn't exist) will be assigned to the target of the "as" clause, if there is one. """ if item in obj: real_val = obj[item] obj[item] = new_val try: yield real_val finally: obj[item] = real_val else: obj[item] = new_val try: yield finally: if item in obj: del obj[item] def args_from_interpreter_flags(): """Return a list of command-line arguments reproducing the current settings in sys.flags and sys.warnoptions.""" import subprocess return subprocess._args_from_interpreter_flags() def optim_args_from_interpreter_flags(): """Return a list of command-line arguments reproducing the current optimization settings in sys.flags.""" import subprocess return subprocess._optim_args_from_interpreter_flags() 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 _buggy_ucrt = None def skip_if_buggy_ucrt_strfptime(test): """ Skip decorator for tests that use buggy strptime/strftime If the UCRT bugs are present time.localtime().tm_zone will be an empty string, otherwise we assume the UCRT bugs are fixed See bpo-37552 [Windows] strptime/strftime return invalid results with UCRT version 17763.615 """ import locale global _buggy_ucrt if _buggy_ucrt is None: if(sys.platform == 'win32' and locale.getdefaultlocale()[1] == 'cp65001' and time.localtime().tm_zone == ''): _buggy_ucrt = True else: _buggy_ucrt = False return unittest.skip("buggy MSVC UCRT strptime/strftime")(test) if _buggy_ucrt else test class PythonSymlink: """Creates a symlink for the current Python executable""" def __init__(self, link=None): self.link = link or os.path.abspath(TESTFN) self._linked = [] self.real = os.path.realpath(sys.executable) self._also_link = [] self._env = None self._platform_specific() def _platform_specific(self): pass if sys.platform == "win32": def _platform_specific(self): import glob import _winapi if os.path.lexists(self.real) and not os.path.exists(self.real): # App symlink appears to not exist, but we want the # real executable here anyway self.real = _winapi.GetModuleFileName(0) dll = _winapi.GetModuleFileName(sys.dllhandle) src_dir = os.path.dirname(dll) dest_dir = os.path.dirname(self.link) self._also_link.append(( dll, os.path.join(dest_dir, os.path.basename(dll)) )) for runtime in glob.glob(os.path.join(glob.escape(src_dir), "vcruntime*.dll")): self._also_link.append(( runtime, os.path.join(dest_dir, os.path.basename(runtime)) )) self._env = {k.upper(): os.getenv(k) for k in os.environ} self._env["PYTHONHOME"] = os.path.dirname(self.real) if sysconfig.is_python_build(True): self._env["PYTHONPATH"] = os.path.dirname(os.__file__) def __enter__(self): os.symlink(self.real, self.link) self._linked.append(self.link) for real, link in self._also_link: os.symlink(real, link) self._linked.append(link) return self def __exit__(self, exc_type, exc_value, exc_tb): for link in self._linked: try: os.remove(link) except IOError as ex: if verbose: print("failed to clean up {}: {}".format(link, ex)) def _call(self, python, args, env, returncode): import subprocess cmd = [python, *args] p = subprocess.Popen(cmd, stdout=subprocess.PIPE, stderr=subprocess.PIPE, env=env) r = p.communicate() if p.returncode != returncode: if verbose: print(repr(r[0])) print(repr(r[1]), file=sys.stderr) raise RuntimeError( 'unexpected return code: {0} (0x{0:08X})'.format(p.returncode)) return r def call_real(self, *args, returncode=0): return self._call(self.real, args, None, returncode) def call_link(self, *args, returncode=0): return self._call(self.link, args, self._env, returncode) def skip_if_pgo_task(test): """Skip decorator for tests not run in (non-extended) PGO task""" ok = not PGO or PGO_EXTENDED msg = "Not run for (non-extended) PGO task" return test if ok else unittest.skip(msg)(test) def detect_api_mismatch(ref_api, other_api, *, ignore=()): """Returns the set of items in ref_api not in other_api, except for a defined list of items to be ignored in this check. By default this skips private attributes beginning with '_' but includes all magic methods, i.e. those starting and ending in '__'. """ missing_items = set(dir(ref_api)) - set(dir(other_api)) if ignore: missing_items -= set(ignore) missing_items = set(m for m in missing_items if not m.startswith('_') or m.endswith('__')) return missing_items def check__all__(test_case, module, name_of_module=None, extra=(), blacklist=()): """Assert that the __all__ variable of 'module' contains all public names. The module's public names (its API) are detected automatically based on whether they match the public name convention and were defined in 'module'. The 'name_of_module' argument can specify (as a string or tuple thereof) what module(s) an API could be defined in in order to be detected as a public API. One case for this is when 'module' imports part of its public API from other modules, possibly a C backend (like 'csv' and its '_csv'). The 'extra' argument can be a set of names that wouldn't otherwise be automatically detected as "public", like objects without a proper '__module__' attribute. If provided, it will be added to the automatically detected ones. The 'blacklist' argument can be a set of names that must not be treated as part of the public API even though their names indicate otherwise. Usage: import bar import foo import unittest from test import support class MiscTestCase(unittest.TestCase): def test__all__(self): support.check__all__(self, foo) class OtherTestCase(unittest.TestCase): def test__all__(self): extra = {'BAR_CONST', 'FOO_CONST'} blacklist = {'baz'} # Undocumented name. # bar imports part of its API from _bar. support.check__all__(self, bar, ('bar', '_bar'), extra=extra, blacklist=blacklist) """ if name_of_module is None: name_of_module = (module.__name__, ) elif isinstance(name_of_module, str): name_of_module = (name_of_module, ) expected = set(extra) for name in dir(module): if name.startswith('_') or name in blacklist: continue obj = getattr(module, name) if (getattr(obj, '__module__', None) in name_of_module or (not hasattr(obj, '__module__') and not isinstance(obj, types.ModuleType))): expected.add(name) test_case.assertCountEqual(module.__all__, expected) def suppress_msvcrt_asserts(verbose=False): try: import msvcrt except ImportError: return msvcrt.SetErrorMode(msvcrt.SEM_FAILCRITICALERRORS | msvcrt.SEM_NOALIGNMENTFAULTEXCEPT | msvcrt.SEM_NOGPFAULTERRORBOX | msvcrt.SEM_NOOPENFILEERRORBOX) # CrtSetReportMode() is only available in debug build if hasattr(msvcrt, 'CrtSetReportMode'): for m in [msvcrt.CRT_WARN, msvcrt.CRT_ERROR, msvcrt.CRT_ASSERT]: if verbose: msvcrt.CrtSetReportMode(m, msvcrt.CRTDBG_MODE_FILE) msvcrt.CrtSetReportFile(m, msvcrt.CRTDBG_FILE_STDERR) else: msvcrt.CrtSetReportMode(m, 0) 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 old_modes = None def __enter__(self): """On Windows, disable Windows Error Reporting dialogs using SetErrorMode() and CrtSetReportMode(). On UNIX, try to save the previous core file size limit, then set soft limit to 0. """ if sys.platform.startswith('win'): # see http://msdn.microsoft.com/en-us/library/windows/desktop/ms680621.aspx try: import msvcrt except ImportError: return self.old_value = msvcrt.GetErrorMode() msvcrt.SetErrorMode(self.old_value | msvcrt.SEM_NOGPFAULTERRORBOX) # bpo-23314: Suppress assert dialogs in debug builds. # CrtSetReportMode() is only available in debug build. if hasattr(msvcrt, 'CrtSetReportMode'): self.old_modes = {} for report_type in [msvcrt.CRT_WARN, msvcrt.CRT_ERROR, msvcrt.CRT_ASSERT]: old_mode = msvcrt.CrtSetReportMode(report_type, msvcrt.CRTDBG_MODE_FILE) old_file = msvcrt.CrtSetReportFile(report_type, msvcrt.CRTDBG_FILE_STDERR) self.old_modes[report_type] = old_mode, old_file else: try: import resource self.resource = resource except ImportError: self.resource = None if self.resource is not None: try: self.old_value = self.resource.getrlimit(self.resource.RLIMIT_CORE) self.resource.setrlimit(self.resource.RLIMIT_CORE, (0, self.old_value[1])) except (ValueError, OSError): pass if sys.platform == 'darwin': import subprocess # 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. cmd = ['/usr/bin/defaults', 'read', 'com.apple.CrashReporter', 'DialogType'] proc = subprocess.Popen(cmd, stdout=subprocess.PIPE, stderr=subprocess.PIPE) with proc: stdout = proc.communicate()[0] if stdout.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: return if sys.platform.startswith('win'): import msvcrt msvcrt.SetErrorMode(self.old_value) if self.old_modes: for report_type, (old_mode, old_file) in self.old_modes.items(): msvcrt.CrtSetReportMode(report_type, old_mode) msvcrt.CrtSetReportFile(report_type, old_file) else: if self.resource is not None: try: self.resource.setrlimit(self.resource.RLIMIT_CORE, self.old_value) except (ValueError, OSError): pass 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 try: old_value = object_to_patch.__dict__[attr_name] except (AttributeError, KeyError): old_value = getattr(object_to_patch, attr_name, None) else: 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) else: delattr(object_to_patch, attr_name) test_instance.addCleanup(cleanup) # 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 try: import tracemalloc except ImportError: pass else: 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) def check_free_after_iterating(test, iter, cls, args=()): class A(cls): def __del__(self): nonlocal done done = True try: next(it) except StopIteration: pass done = False it = iter(A(*args)) # Issue 26494: Shouldn't crash test.assertRaises(StopIteration, next, it) # The sequence should be deallocated just after the end of iterating gc_collect() test.assertTrue(done) def missing_compiler_executable(cmd_names=[]): """Check if the compiler components used to build the interpreter exist. Check for the existence of the compiler executables whose names are listed in 'cmd_names' or all the compiler executables when 'cmd_names' is empty and return the first missing executable or None when none is found missing. """ from distutils import ccompiler, sysconfig, spawn compiler = ccompiler.new_compiler() sysconfig.customize_compiler(compiler) for name in compiler.executables: if cmd_names and name not in cmd_names: continue cmd = getattr(compiler, name) if cmd_names: assert cmd is not None, \ "the '%s' executable is not configured" % name elif not cmd: continue if spawn.find_executable(cmd[0]) is None: return cmd[0] _is_android_emulator = None def setswitchinterval(interval): # Setting a very low gil interval on the Android emulator causes python # to hang (issue #26939). minimum_interval = 1e-5 if is_android and interval < minimum_interval: global _is_android_emulator if _is_android_emulator is None: import subprocess _is_android_emulator = (subprocess.check_output( ['getprop', 'ro.kernel.qemu']).strip() == b'1') if _is_android_emulator: interval = minimum_interval return sys.setswitchinterval(interval) @contextlib.contextmanager def disable_faulthandler(): import faulthandler # use sys.__stderr__ instead of sys.stderr, since regrtest replaces # sys.stderr with a StringIO which has no file descriptor when a test # is run with -W/--verbose3. fd = sys.__stderr__.fileno() is_enabled = faulthandler.is_enabled() try: faulthandler.disable() yield finally: if is_enabled: faulthandler.enable(file=fd, all_threads=True) class SaveSignals: """ Save and restore signal handlers. This class is only able to save/restore signal handlers registered by the Python signal module: see bpo-13285 for "external" signal handlers. """ def __init__(self): import signal self.signal = signal self.signals = signal.valid_signals() # SIGKILL and SIGSTOP signals cannot be ignored nor caught for signame in ('SIGKILL', 'SIGSTOP'): try: signum = getattr(signal, signame) except AttributeError: continue self.signals.remove(signum) self.handlers = {} def save(self): for signum in self.signals: handler = self.signal.getsignal(signum) if handler is None: # getsignal() returns None if a signal handler was not # registered by the Python signal module, # and the handler is not SIG_DFL nor SIG_IGN. # # Ignore the signal: we cannot restore the handler. continue self.handlers[signum] = handler def restore(self): for signum, handler in self.handlers.items(): self.signal.signal(signum, handler) def with_pymalloc(): import _testcapi return _testcapi.WITH_PYMALLOC class _ALWAYS_EQ: """ Object that is equal to anything. """ def __eq__(self, other): return True def __ne__(self, other): return False ALWAYS_EQ = _ALWAYS_EQ() class _NEVER_EQ: """ Object that is not equal to anything. """ def __eq__(self, other): return False def __ne__(self, other): return True def __hash__(self): return 1 NEVER_EQ = _NEVER_EQ() @functools.total_ordering class _LARGEST: """ Object that is greater than anything (except itself). """ def __eq__(self, other): return isinstance(other, _LARGEST) def __lt__(self, other): return False LARGEST = _LARGEST() @functools.total_ordering class _SMALLEST: """ Object that is less than anything (except itself). """ def __eq__(self, other): return isinstance(other, _SMALLEST) def __gt__(self, other): return False SMALLEST = _SMALLEST() def maybe_get_event_loop_policy(): """Return the global event loop policy if one is set, else return None.""" import asyncio.events return asyncio.events._event_loop_policy # Helpers for testing hashing. NHASHBITS = sys.hash_info.width # number of bits in hash() result assert NHASHBITS in (32, 64) # Return mean and sdev of number of collisions when tossing nballs balls # uniformly at random into nbins bins. By definition, the number of # collisions is the number of balls minus the number of occupied bins at # the end. def collision_stats(nbins, nballs): n, k = nbins, nballs # prob a bin empty after k trials = (1 - 1/n)**k # mean # empty is then n * (1 - 1/n)**k # so mean # occupied is n - n * (1 - 1/n)**k # so collisions = k - (n - n*(1 - 1/n)**k) # # For the variance: # n*(n-1)*(1-2/n)**k + meanempty - meanempty**2 = # n*(n-1)*(1-2/n)**k + meanempty * (1 - meanempty) # # Massive cancellation occurs, and, e.g., for a 64-bit hash code # 1-1/2**64 rounds uselessly to 1.0. Rather than make heroic (and # error-prone) efforts to rework the naive formulas to avoid those, # we use the `decimal` module to get plenty of extra precision. # # Note: the exact values are straightforward to compute with # rationals, but in context that's unbearably slow, requiring # multi-million bit arithmetic. import decimal with decimal.localcontext() as ctx: bits = n.bit_length() * 2 # bits in n**2 # At least that many bits will likely cancel out. # Use that many decimal digits instead. ctx.prec = max(bits, 30) dn = decimal.Decimal(n) p1empty = ((dn - 1) / dn) ** k meanempty = n * p1empty occupied = n - meanempty collisions = k - occupied var = dn*(dn-1)*((dn-2)/dn)**k + meanempty * (1 - meanempty) return float(collisions), float(var.sqrt()) class catch_unraisable_exception: """ Context manager catching unraisable exception using sys.unraisablehook. Storing the exception value (cm.unraisable.exc_value) creates a reference cycle. The reference cycle is broken explicitly when the context manager exits. Storing the object (cm.unraisable.object) can resurrect it if it is set to an object which is being finalized. Exiting the context manager clears the stored object. Usage: with support.catch_unraisable_exception() as cm: # code creating an "unraisable exception" ... # check the unraisable exception: use cm.unraisable ... # cm.unraisable attribute no longer exists at this point # (to break a reference cycle) """ def __init__(self): self.unraisable = None self._old_hook = None def _hook(self, unraisable): # Storing unraisable.object can resurrect an object which is being # finalized. Storing unraisable.exc_value creates a reference cycle. self.unraisable = unraisable def __enter__(self): self._old_hook = sys.unraisablehook sys.unraisablehook = self._hook return self def __exit__(self, *exc_info): sys.unraisablehook = self._old_hook del self.unraisable def wait_process(pid, *, exitcode, timeout=None): """ Wait until process pid completes and check that the process exit code is exitcode. Raise an AssertionError if the process exit code is not equal to exitcode. If the process runs longer than timeout seconds (SHORT_TIMEOUT by default), kill the process (if signal.SIGKILL is available) and raise an AssertionError. The timeout feature is not available on Windows. """ if os.name != "nt": import signal if timeout is None: timeout = SHORT_TIMEOUT t0 = time.monotonic() sleep = 0.001 max_sleep = 0.1 while True: pid2, status = os.waitpid(pid, os.WNOHANG) if pid2 != 0: break # process is still running dt = time.monotonic() - t0 if dt > SHORT_TIMEOUT: try: os.kill(pid, signal.SIGKILL) os.waitpid(pid, 0) except OSError: # Ignore errors like ChildProcessError or PermissionError pass raise AssertionError(f"process {pid} is still running " f"after {dt:.1f} seconds") sleep = min(sleep * 2, max_sleep) time.sleep(sleep) else: # Windows implementation pid2, status = os.waitpid(pid, 0) exitcode2 = os.waitstatus_to_exitcode(status) if exitcode2 != exitcode: raise AssertionError(f"process {pid} exited with code {exitcode2}, " f"but exit code {exitcode} is expected") # sanity check: it should not fail in practice if pid2 != pid: raise AssertionError(f"pid {pid2} != pid {pid}") def skip_if_broken_multiprocessing_synchronize(): """ Skip tests if the multiprocessing.synchronize module is missing, if there is no available semaphore implementation, or if creating a lock raises an OSError (on Linux only). """ # Skip tests if the _multiprocessing extension is missing. import_module('_multiprocessing') # Skip tests if there is no available semaphore implementation: # multiprocessing.synchronize requires _multiprocessing.SemLock. synchronize = import_module('multiprocessing.synchronize') if sys.platform == "linux": try: # bpo-38377: On Linux, creating a semaphore fails with OSError # if the current user does not have the permission to create # a file in /dev/shm/ directory. synchronize.Lock(ctx=None) except OSError as exc: raise unittest.SkipTest(f"broken multiprocessing SemLock: {exc!r}")