Lib/test/test_sys.py

import builtins
import codecs
import gc
import io
import locale
import operator
import os
import random
import shutil
import socket
import struct
import subprocess
import sys
import sysconfig
import test.support
from io import StringIO
from unittest import mock
from test import support
from test.support import os_helper
from test.support.script_helper import assert_python_ok, assert_python_failure
from test.support.socket_helper import find_unused_port
from test.support import threading_helper
from test.support import import_helper
from test.support import force_not_colorized
from test.support import SHORT_TIMEOUT
try:
    from concurrent import interpreters
except ImportError:
    interpreters = None
import textwrap
import unittest
import warnings


def requires_subinterpreters(meth):
    """Decorator to skip a test if subinterpreters are not supported."""
    return unittest.skipIf(interpreters is None,
                           'subinterpreters required')(meth)


DICT_KEY_STRUCT_FORMAT = 'n2BI2n'

class DisplayHookTest(unittest.TestCase):

    def test_original_displayhook(self):
        dh = sys.__displayhook__

        with support.captured_stdout() as out:
            dh(42)

        self.assertEqual(out.getvalue(), "42\n")
        self.assertEqual(builtins._, 42)

        del builtins._

        with support.captured_stdout() as out:
            dh(None)

        self.assertEqual(out.getvalue(), "")
        self.assertNotHasAttr(builtins, "_")

        # sys.displayhook() requires arguments
        self.assertRaises(TypeError, dh)

        stdout = sys.stdout
        try:
            del sys.stdout
            self.assertRaises(RuntimeError, dh, 42)
        finally:
            sys.stdout = stdout

    def test_lost_displayhook(self):
        displayhook = sys.displayhook
        try:
            del sys.displayhook
            code = compile("42", "<string>", "single")
            self.assertRaises(RuntimeError, eval, code)
        finally:
            sys.displayhook = displayhook

    def test_custom_displayhook(self):
        def baddisplayhook(obj):
            raise ValueError

        with support.swap_attr(sys, 'displayhook', baddisplayhook):
            code = compile("42", "<string>", "single")
            self.assertRaises(ValueError, eval, code)

    def test_gh130163(self):
        class X:
            def __repr__(self):
                sys.stdout = io.StringIO()
                support.gc_collect()
                return 'foo'

        with support.swap_attr(sys, 'stdout', None):
            sys.stdout = io.StringIO()  # the only reference
            sys.displayhook(X())  # should not crash


class ActiveExceptionTests(unittest.TestCase):
    def test_exc_info_no_exception(self):
        self.assertEqual(sys.exc_info(), (None, None, None))

    def test_sys_exception_no_exception(self):
        self.assertEqual(sys.exception(), None)

    def test_exc_info_with_exception_instance(self):
        def f():
            raise ValueError(42)

        try:
            f()
        except Exception as e_:
            e = e_
            exc_info = sys.exc_info()

        self.assertIsInstance(e, ValueError)
        self.assertIs(exc_info[0], ValueError)
        self.assertIs(exc_info[1], e)
        self.assertIs(exc_info[2], e.__traceback__)

    def test_exc_info_with_exception_type(self):
        def f():
            raise ValueError

        try:
            f()
        except Exception as e_:
            e = e_
            exc_info = sys.exc_info()

        self.assertIsInstance(e, ValueError)
        self.assertIs(exc_info[0], ValueError)
        self.assertIs(exc_info[1], e)
        self.assertIs(exc_info[2], e.__traceback__)

    def test_sys_exception_with_exception_instance(self):
        def f():
            raise ValueError(42)

        try:
            f()
        except Exception as e_:
            e = e_
            exc = sys.exception()

        self.assertIsInstance(e, ValueError)
        self.assertIs(exc, e)

    def test_sys_exception_with_exception_type(self):
        def f():
            raise ValueError

        try:
            f()
        except Exception as e_:
            e = e_
            exc = sys.exception()

        self.assertIsInstance(e, ValueError)
        self.assertIs(exc, e)


class ExceptHookTest(unittest.TestCase):

    @force_not_colorized
    def test_original_excepthook(self):
        try:
            raise ValueError(42)
        except ValueError as exc:
            with support.captured_stderr() as err:
                sys.__excepthook__(*sys.exc_info())

        self.assertEndsWith(err.getvalue(), "ValueError: 42\n")

        self.assertRaises(TypeError, sys.__excepthook__)

    @force_not_colorized
    def test_excepthook_bytes_filename(self):
        # bpo-37467: sys.excepthook() must not crash if a filename
        # is a bytes string
        with warnings.catch_warnings():
            warnings.simplefilter('ignore', BytesWarning)

            try:
                raise SyntaxError("msg", (b"bytes_filename", 123, 0, "text"))
            except SyntaxError as exc:
                with support.captured_stderr() as err:
                    sys.__excepthook__(*sys.exc_info())

        err = err.getvalue()
        self.assertIn("""  File "b'bytes_filename'", line 123\n""", err)
        self.assertIn("""    text\n""", err)
        self.assertEndsWith(err, "SyntaxError: msg\n")

    def test_excepthook(self):
        with test.support.captured_output("stderr") as stderr:
            with test.support.catch_unraisable_exception():
                sys.excepthook(1, '1', 1)
        self.assertTrue("TypeError: print_exception(): Exception expected for " \
                         "value, str found" in stderr.getvalue())

    # FIXME: testing the code for a lost or replaced excepthook in
    # Python/pythonrun.c::PyErr_PrintEx() is tricky.


class SysModuleTest(unittest.TestCase):

    def tearDown(self):
        test.support.reap_children()

    def test_exit(self):
        # call with two arguments
        self.assertRaises(TypeError, sys.exit, 42, 42)

        # call without argument
        with self.assertRaises(SystemExit) as cm:
            sys.exit()
        self.assertIsNone(cm.exception.code)

        rc, out, err = assert_python_ok('-c', 'import sys; sys.exit()')
        self.assertEqual(rc, 0)
        self.assertEqual(out, b'')
        self.assertEqual(err, b'')

        # gh-125842: Windows uses 32-bit unsigned integers for exit codes
        # so a -1 exit code is sometimes interpreted as 0xffff_ffff.
        rc, out, err = assert_python_failure('-c', 'import sys; sys.exit(0xffff_ffff)')
        self.assertIn(rc, (-1, 0xff, 0xffff_ffff))
        self.assertEqual(out, b'')
        self.assertEqual(err, b'')

        # Overflow results in a -1 exit code, which may be converted to 0xff
        # or 0xffff_ffff.
        rc, out, err = assert_python_failure('-c', 'import sys; sys.exit(2**128)')
        self.assertIn(rc, (-1, 0xff, 0xffff_ffff))
        self.assertEqual(out, b'')
        self.assertEqual(err, b'')

        # call with integer argument
        with self.assertRaises(SystemExit) as cm:
            sys.exit(42)
        self.assertEqual(cm.exception.code, 42)

        # call with tuple argument with one entry
        # entry will be unpacked
        with self.assertRaises(SystemExit) as cm:
            sys.exit((42,))
        self.assertEqual(cm.exception.code, 42)

        # call with string argument
        with self.assertRaises(SystemExit) as cm:
            sys.exit("exit")
        self.assertEqual(cm.exception.code, "exit")

        # call with tuple argument with two entries
        with self.assertRaises(SystemExit) as cm:
            sys.exit((17, 23))
        self.assertEqual(cm.exception.code, (17, 23))

        # test that the exit machinery handles SystemExits properly
        rc, out, err = assert_python_failure('-c', 'raise SystemExit(47)')
        self.assertEqual(rc, 47)
        self.assertEqual(out, b'')
        self.assertEqual(err, b'')

        def check_exit_message(code, expected, **env_vars):
            rc, out, err = assert_python_failure('-c', code, **env_vars)
            self.assertEqual(rc, 1)
            self.assertEqual(out, b'')
            self.assertStartsWith(err, expected)

        # test that stderr buffer is flushed before the exit message is written
        # into stderr
        check_exit_message(
            r'import sys; sys.stderr.write("unflushed,"); sys.exit("message")',
            b"unflushed,message")

        # test that the exit message is written with backslashreplace error
        # handler to stderr
        check_exit_message(
            r'import sys; sys.exit("surrogates:\uDCFF")',
            b"surrogates:\\udcff")

        # test that the unicode message is encoded to the stderr encoding
        # instead of the default encoding (utf8)
        check_exit_message(
            r'import sys; sys.exit("h\xe9")',
            b"h\xe9", PYTHONIOENCODING='latin-1')

    @support.requires_subprocess()
    def test_exit_codes_under_repl(self):
        # GH-129900: SystemExit, or things that raised it, didn't
        # get their return code propagated by the REPL
        import tempfile

        exit_ways = [
            "exit",
            "__import__('sys').exit",
            "raise SystemExit"
        ]

        for exitfunc in exit_ways:
            for return_code in (0, 123):
                with self.subTest(exitfunc=exitfunc, return_code=return_code):
                    with tempfile.TemporaryFile("w+") as stdin:
                        stdin.write(f"{exitfunc}({return_code})\n")
                        stdin.seek(0)
                        proc = subprocess.run([sys.executable], stdin=stdin)
                        self.assertEqual(proc.returncode, return_code)

    def test_getdefaultencoding(self):
        self.assertRaises(TypeError, sys.getdefaultencoding, 42)
        # can't check more than the type, as the user might have changed it
        self.assertIsInstance(sys.getdefaultencoding(), str)

    # testing sys.settrace() is done in test_sys_settrace.py
    # testing sys.setprofile() is done in test_sys_setprofile.py

    def test_switchinterval(self):
        self.assertRaises(TypeError, sys.setswitchinterval)
        self.assertRaises(TypeError, sys.setswitchinterval, "a")
        self.assertRaises(ValueError, sys.setswitchinterval, -1.0)
        self.assertRaises(ValueError, sys.setswitchinterval, 0.0)
        orig = sys.getswitchinterval()
        # sanity check
        self.assertTrue(orig < 0.5, orig)
        try:
            for n in 0.00001, 0.05, 3.0, orig:
                sys.setswitchinterval(n)
                self.assertAlmostEqual(sys.getswitchinterval(), n)
        finally:
            sys.setswitchinterval(orig)

    def test_getrecursionlimit(self):
        limit = sys.getrecursionlimit()
        self.assertIsInstance(limit, int)
        self.assertGreater(limit, 1)

        self.assertRaises(TypeError, sys.getrecursionlimit, 42)

    def test_setrecursionlimit(self):
        old_limit = sys.getrecursionlimit()
        try:
            sys.setrecursionlimit(10_005)
            self.assertEqual(sys.getrecursionlimit(), 10_005)

            self.assertRaises(TypeError, sys.setrecursionlimit)
            self.assertRaises(ValueError, sys.setrecursionlimit, -42)
        finally:
            sys.setrecursionlimit(old_limit)

    def test_recursionlimit_recovery(self):
        if hasattr(sys, 'gettrace') and sys.gettrace():
            self.skipTest('fatal error if run with a trace function')

        old_limit = sys.getrecursionlimit()
        def f():
            f()
        try:
            for depth in (50, 75, 100, 250, 1000):
                try:
                    sys.setrecursionlimit(depth)
                except RecursionError:
                    # Issue #25274: The recursion limit is too low at the
                    # current recursion depth
                    continue

                # Issue #5392: test stack overflow after hitting recursion
                # limit twice
                with self.assertRaises(RecursionError):
                    f()
                with self.assertRaises(RecursionError):
                    f()
        finally:
            sys.setrecursionlimit(old_limit)

    @test.support.cpython_only
    def test_setrecursionlimit_to_depth(self):
        # Issue #25274: Setting a low recursion limit must be blocked if the
        # current recursion depth is already higher than limit.

        old_limit = sys.getrecursionlimit()
        try:
            depth = support.get_recursion_depth()
            with self.subTest(limit=sys.getrecursionlimit(), depth=depth):
                # depth + 1 is OK
                sys.setrecursionlimit(depth + 1)

                # reset the limit to be able to call self.assertRaises()
                # context manager
                sys.setrecursionlimit(old_limit)
                with self.assertRaises(RecursionError) as cm:
                    sys.setrecursionlimit(depth)
            self.assertRegex(str(cm.exception),
                             "cannot set the recursion limit to [0-9]+ "
                             "at the recursion depth [0-9]+: "
                             "the limit is too low")
        finally:
            sys.setrecursionlimit(old_limit)

    def test_getwindowsversion(self):
        # Raise SkipTest if sys doesn't have getwindowsversion attribute
        test.support.get_attribute(sys, "getwindowsversion")
        v = sys.getwindowsversion()
        self.assertEqual(len(v), 5)
        self.assertIsInstance(v[0], int)
        self.assertIsInstance(v[1], int)
        self.assertIsInstance(v[2], int)
        self.assertIsInstance(v[3], int)
        self.assertIsInstance(v[4], str)
        self.assertRaises(IndexError, operator.getitem, v, 5)
        self.assertIsInstance(v.major, int)
        self.assertIsInstance(v.minor, int)
        self.assertIsInstance(v.build, int)
        self.assertIsInstance(v.platform, int)
        self.assertIsInstance(v.service_pack, str)
        self.assertIsInstance(v.service_pack_minor, int)
        self.assertIsInstance(v.service_pack_major, int)
        self.assertIsInstance(v.suite_mask, int)
        self.assertIsInstance(v.product_type, int)
        self.assertEqual(v[0], v.major)
        self.assertEqual(v[1], v.minor)
        self.assertEqual(v[2], v.build)
        self.assertEqual(v[3], v.platform)
        self.assertEqual(v[4], v.service_pack)
        support.check_immutable_type(self, type(v))

        # This is how platform.py calls it. Make sure tuple
        #  still has 5 elements
        maj, min, buildno, plat, csd = sys.getwindowsversion()

    def test_call_tracing(self):
        self.assertRaises(TypeError, sys.call_tracing, type, 2)

    @unittest.skipUnless(hasattr(sys, "setdlopenflags"),
                         'test needs sys.setdlopenflags()')
    def test_dlopenflags(self):
        self.assertHasAttr(sys, "getdlopenflags")
        self.assertRaises(TypeError, sys.getdlopenflags, 42)
        oldflags = sys.getdlopenflags()
        self.assertRaises(TypeError, sys.setdlopenflags)
        sys.setdlopenflags(oldflags+1)
        self.assertEqual(sys.getdlopenflags(), oldflags+1)
        sys.setdlopenflags(oldflags)

    @test.support.refcount_test
    def test_refcount(self):
        # n here originally had to be a global in order for this test to pass
        # while tracing with a python function. Tracing used to call
        # PyFrame_FastToLocals, which would add a copy of any locals to the
        # frame object, causing the ref count to increase by 2 instead of 1.
        # While that no longer happens (due to PEP 667), this test case retains
        # its original global-based implementation
        # PEP 683's immortal objects also made this point moot, since the
        # refcount for None doesn't change anyway. Maybe this test should be
        # using a different constant value? (e.g. an integer)
        global n
        self.assertRaises(TypeError, sys.getrefcount)
        c = sys.getrefcount(None)
        n = None
        # Singleton refcnts don't change
        self.assertEqual(sys.getrefcount(None), c)
        del n
        self.assertEqual(sys.getrefcount(None), c)
        if hasattr(sys, "gettotalrefcount"):
            self.assertIsInstance(sys.gettotalrefcount(), int)

    def test_getframe(self):
        self.assertRaises(TypeError, sys._getframe, 42, 42)
        self.assertRaises(ValueError, sys._getframe, 2000000000)
        self.assertTrue(
            SysModuleTest.test_getframe.__code__ \
            is sys._getframe().f_code
        )

    def test_getframemodulename(self):
        # Default depth gets ourselves
        self.assertEqual(__name__, sys._getframemodulename())
        self.assertEqual("unittest.case", sys._getframemodulename(1))
        i = 0
        f = sys._getframe(i)
        while f:
            self.assertEqual(
                f.f_globals['__name__'],
                sys._getframemodulename(i) or '__main__'
            )
            i += 1
            f2 = f.f_back
            try:
                f = sys._getframe(i)
            except ValueError:
                break
            self.assertIs(f, f2)
        self.assertIsNone(sys._getframemodulename(i))

    @support.cpython_only  # sys._current_frames() is a CPython-only gimmick.
    @threading_helper.reap_threads
    @threading_helper.requires_working_threading()
    def test_current_frames(self):
        import threading
        import traceback

        # Spawn a thread that blocks at a known place.  Then the main
        # thread does sys._current_frames(), and verifies that the frames
        # returned make sense.
        entered_g = threading.Event()
        leave_g = threading.Event()
        thread_info = []  # the thread's id

        def f123():
            g456()

        def g456():
            thread_info.append(threading.get_ident())
            entered_g.set()
            leave_g.wait()

        t = threading.Thread(target=f123)
        t.start()
        entered_g.wait()

        try:
            # At this point, t has finished its entered_g.set(), although it's
            # impossible to guess whether it's still on that line or has moved on
            # to its leave_g.wait().
            self.assertEqual(len(thread_info), 1)
            thread_id = thread_info[0]

            d = sys._current_frames()
            for tid in d:
                self.assertIsInstance(tid, int)
                self.assertGreater(tid, 0)

            main_id = threading.get_ident()
            self.assertIn(main_id, d)
            self.assertIn(thread_id, d)

            # Verify that the captured main-thread frame is _this_ frame.
            frame = d.pop(main_id)
            self.assertTrue(frame is sys._getframe())

            # Verify that the captured thread frame is blocked in g456, called
            # from f123.  This is a little tricky, since various bits of
            # threading.py are also in the thread's call stack.
            frame = d.pop(thread_id)
            stack = traceback.extract_stack(frame)
            for i, (filename, lineno, funcname, sourceline) in enumerate(stack):
                if funcname == "f123":
                    break
            else:
                self.fail("didn't find f123() on thread's call stack")

            self.assertEqual(sourceline, "g456()")

            # And the next record must be for g456().
            filename, lineno, funcname, sourceline = stack[i+1]
            self.assertEqual(funcname, "g456")
            self.assertIn(sourceline, ["leave_g.wait()", "entered_g.set()"])
        finally:
            # Reap the spawned thread.
            leave_g.set()
            t.join()

    @support.cpython_only
    @requires_subinterpreters
    @threading_helper.requires_working_threading()
    def test_current_frames_other_interpreters(self):
        # gh-158364: sys._current_frames() would access frames of another
        # interpreter and crash
        import threading

        entered = threading.Event()
        left = threading.Event()

        def park():
            entered.set()
            left.wait()

        t = threading.Thread(target=park)
        with threading_helper.start_threads([t], unlock=left.set):
            entered.wait()
            interp = interpreters.create()
            try:
                interp.exec(f"""if True:
                    import sys
                    import threading

                    frames = sys._current_frames()
                    assert threading.get_ident() in frames, frames
                    assert frames[threading.get_ident()].f_globals is globals()
                    assert {t.ident} not in frames, frames
                    """)
            finally:
                interp.close()

    @threading_helper.reap_threads
    @threading_helper.requires_working_threading()
    def test_current_exceptions(self):
        import threading
        import traceback

        # Spawn a thread that blocks at a known place.  Then the main
        # thread does sys._current_frames(), and verifies that the frames
        # returned make sense.
        g_raised = threading.Event()
        leave_g = threading.Event()
        thread_info = []  # the thread's id

        def f123():
            g456()

        def g456():
            thread_info.append(threading.get_ident())
            while True:
                try:
                    raise ValueError("oops")
                except ValueError:
                    g_raised.set()
                    if leave_g.wait(timeout=support.LONG_TIMEOUT):
                        break

        t = threading.Thread(target=f123)
        t.start()
        g_raised.wait(timeout=support.LONG_TIMEOUT)

        try:
            self.assertEqual(len(thread_info), 1)
            thread_id = thread_info[0]

            d = sys._current_exceptions()
            for tid in d:
                self.assertIsInstance(tid, int)
                self.assertGreater(tid, 0)

            main_id = threading.get_ident()
            self.assertIn(main_id, d)
            self.assertIn(thread_id, d)
            self.assertEqual(None, d.pop(main_id))

            # Verify that the captured thread frame is blocked in g456, called
            # from f123.  This is a little tricky, since various bits of
            # threading.py are also in the thread's call stack.
            exc_value = d.pop(thread_id)
            stack = traceback.extract_stack(exc_value.__traceback__.tb_frame)
            for i, (filename, lineno, funcname, sourceline) in enumerate(stack):
                if funcname == "f123":
                    break
            else:
                self.fail("didn't find f123() on thread's call stack")

            self.assertEqual(sourceline, "g456()")

            # And the next record must be for g456().
            filename, lineno, funcname, sourceline = stack[i+1]
            self.assertEqual(funcname, "g456")
            self.assertStartsWith(sourceline, ("if leave_g.wait(", "g_raised.set()"))
        finally:
            # Reap the spawned thread.
            leave_g.set()
            t.join()

    @support.cpython_only
    @requires_subinterpreters
    @threading_helper.requires_working_threading()
    def test_current_exceptions_other_interpreters(self):
        # gh-158364: sys._current_exceptions() would hand out exceptions of
        # another interpreter and crash
        import threading

        entered = threading.Event()
        left = threading.Event()

        def hold():
            # The thread has to be handling an exception, otherwise
            # sys._current_exceptions() has nothing to report for it.
            try:
                raise ValueError
            except ValueError:
                entered.set()
                left.wait()

        t = threading.Thread(target=hold)
        with threading_helper.start_threads([t], unlock=left.set):
            entered.wait()
            interp = interpreters.create()
            try:
                interp.exec(f"""if True:
                    import sys

                    assert {t.ident} not in sys._current_exceptions()
                    """)
            finally:
                interp.close()

    def test_attributes(self):
        self.assertIsInstance(sys.api_version, int)
        self.assertIsInstance(sys.argv, list)
        for arg in sys.argv:
            self.assertIsInstance(arg, str)
        self.assertIsInstance(sys.orig_argv, list)
        for arg in sys.orig_argv:
            self.assertIsInstance(arg, str)
        self.assertIn(sys.byteorder, ("little", "big"))
        self.assertIsInstance(sys.builtin_module_names, tuple)
        self.assertIsInstance(sys.copyright, str)
        self.assertIsInstance(sys.exec_prefix, str)
        self.assertIsInstance(sys.base_exec_prefix, str)
        self.assertIsInstance(sys.executable, str)
        self.assertEqual(len(sys.float_info), 11)
        self.assertEqual(sys.float_info.radix, 2)
        self.assertEqual(len(sys.int_info), 4)
        self.assertTrue(sys.int_info.bits_per_digit % 5 == 0)
        self.assertTrue(sys.int_info.sizeof_digit >= 1)
        self.assertGreaterEqual(sys.int_info.default_max_str_digits, 500)
        self.assertGreaterEqual(sys.int_info.str_digits_check_threshold, 100)
        self.assertGreater(sys.int_info.default_max_str_digits,
                           sys.int_info.str_digits_check_threshold)
        self.assertEqual(type(sys.int_info.bits_per_digit), int)
        self.assertEqual(type(sys.int_info.sizeof_digit), int)
        self.assertIsInstance(sys.int_info.default_max_str_digits, int)
        self.assertIsInstance(sys.int_info.str_digits_check_threshold, int)
        self.assertIsInstance(sys.hexversion, int)

        self.assertEqual(len(sys.hash_info), 9)
        self.assertLess(sys.hash_info.modulus, 2**sys.hash_info.width)
        # sys.hash_info.modulus should be a prime; we do a quick
        # probable primality test (doesn't exclude the possibility of
        # a Carmichael number)
        for x in range(1, 100):
            self.assertEqual(
                pow(x, sys.hash_info.modulus-1, sys.hash_info.modulus),
                1,
                "sys.hash_info.modulus {} is a non-prime".format(
                    sys.hash_info.modulus)
                )
        self.assertIsInstance(sys.hash_info.inf, int)
        self.assertIsInstance(sys.hash_info.nan, int)
        self.assertIsInstance(sys.hash_info.imag, int)
        algo = sysconfig.get_config_var("Py_HASH_ALGORITHM")
        if sys.hash_info.algorithm in {"fnv", "siphash13", "siphash24"}:
            self.assertIn(sys.hash_info.hash_bits, {32, 64})
            self.assertIn(sys.hash_info.seed_bits, {32, 64, 128})

            if algo == 1:
                self.assertEqual(sys.hash_info.algorithm, "siphash24")
            elif algo == 2:
                self.assertEqual(sys.hash_info.algorithm, "fnv")
            elif algo == 3:
                self.assertEqual(sys.hash_info.algorithm, "siphash13")
            else:
                self.assertIn(sys.hash_info.algorithm, {"fnv", "siphash13", "siphash24"})
        else:
            # PY_HASH_EXTERNAL
            self.assertEqual(algo, 0)
        self.assertGreaterEqual(sys.hash_info.cutoff, 0)
        self.assertLess(sys.hash_info.cutoff, 8)
        support.check_immutable_type(self, type(sys.hash_info))

        self.assertIsInstance(sys.maxsize, int)
        self.assertIsInstance(sys.maxunicode, int)
        self.assertEqual(sys.maxunicode, 0x10FFFF)
        self.assertIsInstance(sys.platform, str)
        self.assertIsInstance(sys.prefix, str)
        self.assertIsInstance(sys.base_prefix, str)
        self.assertIsInstance(sys.platlibdir, str)
        self.assertIsInstance(sys.version, str)
        vi = sys.version_info
        self.assertIsInstance(vi[:], tuple)
        self.assertEqual(len(vi), 5)
        self.assertIsInstance(vi[0], int)
        self.assertIsInstance(vi[1], int)
        self.assertIsInstance(vi[2], int)
        self.assertIn(vi[3], ("alpha", "beta", "candidate", "final"))
        self.assertIsInstance(vi[4], int)
        self.assertIsInstance(vi.major, int)
        self.assertIsInstance(vi.minor, int)
        self.assertIsInstance(vi.micro, int)
        self.assertIn(vi.releaselevel, ("alpha", "beta", "candidate", "final"))
        self.assertIsInstance(vi.serial, int)
        self.assertEqual(vi[0], vi.major)
        self.assertEqual(vi[1], vi.minor)
        self.assertEqual(vi[2], vi.micro)
        self.assertEqual(vi[3], vi.releaselevel)
        self.assertEqual(vi[4], vi.serial)
        self.assertTrue(vi > (1,0,0))
        self.assertIsInstance(sys.float_repr_style, str)
        self.assertIn(sys.float_repr_style, ('short', 'legacy'))
        if not sys.platform.startswith('win'):
            self.assertIsInstance(sys.abiflags, str)
        else:
            self.assertFalse(hasattr(sys, 'abiflags'))

    def test_thread_info(self):
        info = sys.thread_info
        self.assertEqual(len(info), 3)
        self.assertIn(info.name, ('nt', 'pthread', 'pthread-stubs', 'solaris', None))
        self.assertIn(info.lock, ('pymutex', None))
        if sys.platform.startswith(("linux", "android", "freebsd", "wasi")):
            self.assertEqual(info.name, "pthread")
        elif sys.platform == "win32":
            self.assertEqual(info.name, "nt")
        elif sys.platform == "emscripten":
            self.assertIn(info.name, {"pthread", "pthread-stubs"})

    def test_abi_info(self):
        info = sys.abi_info
        info_keys = {'pointer_bits', 'free_threaded', 'debug', 'byteorder'}
        self.assertEqual(set(vars(info)), info_keys)
        pointer_bits = 64 if sys.maxsize > 2**32 else 32
        self.assertEqual(info.pointer_bits, pointer_bits)
        self.assertEqual(info.free_threaded,
                         bool(sysconfig.get_config_var('Py_GIL_DISABLED')))
        self.assertEqual(info.debug,
                         bool(sysconfig.get_config_var('Py_DEBUG')))
        self.assertEqual(info.byteorder, sys.byteorder)

    @unittest.skipUnless(support.is_emscripten, "only available on Emscripten")
    def test_emscripten_info(self):
        self.assertEqual(len(sys._emscripten_info), 4)
        self.assertIsInstance(sys._emscripten_info.emscripten_version, tuple)
        self.assertIsInstance(sys._emscripten_info.runtime, (str, type(None)))
        self.assertIsInstance(sys._emscripten_info.pthreads, bool)
        self.assertIsInstance(sys._emscripten_info.shared_memory, bool)

    def test_43581(self):
        # Can't use sys.stdout, as this is a StringIO object when
        # the test runs under regrtest.
        self.assertEqual(sys.__stdout__.encoding, sys.__stderr__.encoding)

    def test_intern(self):
        has_is_interned = (test.support.check_impl_detail(cpython=True)
                           or hasattr(sys, '_is_interned'))
        self.assertRaises(TypeError, sys.intern)
        self.assertRaises(TypeError, sys.intern, b'abc')
        if has_is_interned:
            self.assertRaises(TypeError, sys._is_interned)
            self.assertRaises(TypeError, sys._is_interned, b'abc')
        s = "never interned before" + str(random.randrange(0, 10**9))
        self.assertTrue(sys.intern(s) is s)
        if has_is_interned:
            self.assertIs(sys._is_interned(s), True)
        s2 = s.swapcase().swapcase()
        if has_is_interned:
            self.assertIs(sys._is_interned(s2), False)
        self.assertTrue(sys.intern(s2) is s)
        if has_is_interned:
            self.assertIs(sys._is_interned(s2), False)

        # Subclasses of string can't be interned, because they
        # provide too much opportunity for insane things to happen.
        # We don't want them in the interned dict and if they aren't
        # actually interned, we don't want to create the appearance
        # that they are by allowing intern() to succeed.
        class S(str):
            def __hash__(self):
                return 123

        self.assertRaises(TypeError, sys.intern, S("abc"))
        if has_is_interned:
            self.assertIs(sys._is_interned(S("abc")), False)

    @support.cpython_only
    @requires_subinterpreters
    def test_subinterp_intern_dynamically_allocated(self):
        # Implementation detail: Dynamically allocated strings
        # are distinct between interpreters
        s = "never interned before" + str(random.randrange(0, 10**9))
        t = sys.intern(s)
        self.assertIs(t, s)

        interp = interpreters.create()
        interp.exec(textwrap.dedent(f'''
            import sys

            # set `s`, avoid parser interning & constant folding
            s = str({s.encode()!r}, 'utf-8')

            t = sys.intern(s)

            assert id(t) != {id(s)}, (id(t), {id(s)})
            assert id(t) != {id(t)}, (id(t), {id(t)})
            '''))

    @support.cpython_only
    @requires_subinterpreters
    def test_subinterp_intern_statically_allocated(self):
        # Implementation detail: Statically allocated strings are shared
        # between interpreters.
        # See Tools/build/generate_global_objects.py for the list
        # of strings that are always statically allocated.
        for s in ('__init__', 'CANCELLED', '<module>', 'utf-8',
                  '{{', '', '\n', '_', 'x', '\0', '\N{CEDILLA}', '\xff',
                  ):
            with self.subTest(s=s):
                t = sys.intern(s)

                interp = interpreters.create()
                interp.exec(textwrap.dedent(f'''
                    import sys

                    # set `s`, avoid parser interning & constant folding
                    s = str({s.encode()!r}, 'utf-8')

                    t = sys.intern(s)
                    assert id(t) == {id(t)}, (id(t), {id(t)})
                    '''))

    @support.cpython_only
    @requires_subinterpreters
    def test_subinterp_intern_singleton(self):
        # Implementation detail: singletons are used for 0- and 1-character
        # latin1 strings.
        for s in '', '\n', '_', 'x', '\0', '\N{CEDILLA}', '\xff':
            with self.subTest(s=s):
                interp = interpreters.create()
                interp.exec(textwrap.dedent(f'''
                    import sys

                    # set `s`, avoid parser interning & constant folding
                    s = str({s.encode()!r}, 'utf-8')

                    assert id(s) == {id(s)}
                    t = sys.intern(s)
                    '''))
                self.assertTrue(sys._is_interned(s))

    def test_sys_flags_indexable_attributes(self):
        self.assertTrue(sys.flags)
        # We've stopped assigning sequence indices to new sys.flags attributes:
        # https://github.com/python/cpython/issues/122575#issuecomment-2416497086
        indexable_attrs = ("debug",
                 "inspect", "interactive", "optimize",
                 "dont_write_bytecode", "no_user_site", "no_site",
                 "ignore_environment", "verbose", "bytes_warning", "quiet",
                 "hash_randomization", "isolated", "dev_mode", "utf8_mode",
                 "warn_default_encoding", "safe_path", "int_max_str_digits")
        for attr_idx, attr in enumerate(indexable_attrs):
            self.assertHasAttr(sys.flags, attr)
            attr_type = bool if attr in ("dev_mode", "safe_path") else int
            self.assertEqual(type(getattr(sys.flags, attr)), attr_type, attr)
            attr_value = getattr(sys.flags, attr)
            self.assertEqual(sys.flags[attr_idx], attr_value,
                             msg=f"sys.flags .{attr} vs [{attr_idx}]")
        self.assertTrue(repr(sys.flags))
        self.assertEqual(len(sys.flags), 18, msg="Do not increase, see GH-122575")

        self.assertIn(sys.flags.utf8_mode, {0, 1, 2})

    def test_sys_flags_name_only_attributes(self):
        # non-tuple sequence fields (name only sys.flags attributes)
        self.assertIsInstance(sys.flags.gil, int|type(None))
        self.assertIsInstance(sys.flags.thread_inherit_context, int|type(None))
        self.assertIsInstance(sys.flags.context_aware_warnings, int|type(None))
        self.assertIsInstance(sys.flags.lazy_imports, int|type(None))

    def assert_raise_on_new_sys_type(self, sys_attr):
        # Users are intentionally prevented from creating new instances of
        # sys.flags, sys.version_info, and sys.getwindowsversion.
        support.check_disallow_instantiation(self, type(sys_attr), sys_attr)

    def test_sys_flags_type(self):
        self.assert_raise_on_new_sys_type(sys.flags)
        support.check_immutable_type(self, type(sys.flags))

    def test_sys_version_info_type(self):
        self.assert_raise_on_new_sys_type(sys.version_info)
        support.check_immutable_type(self, type(sys.version_info))

    def test_sys_getwindowsversion_no_instantiation(self):
        # Skip if not being run on Windows.
        test.support.get_attribute(sys, "getwindowsversion")
        self.assert_raise_on_new_sys_type(sys.getwindowsversion())

    @test.support.cpython_only
    def test_clear_type_cache(self):
        with self.assertWarnsRegex(DeprecationWarning,
                                   r"sys\._clear_type_cache\(\) is deprecated.*"):
            sys._clear_type_cache()

    @force_not_colorized
    @support.requires_subprocess()
    def test_ioencoding(self):
        env = dict(os.environ)

        # Test character: cent sign, encoded as 0x4A (ASCII J) in CP424,
        # not representable in ASCII.

        env["PYTHONIOENCODING"] = "cp424"
        p = subprocess.Popen([sys.executable, "-c", 'print(chr(0xa2))'],
                             stdout = subprocess.PIPE, env=env)
        out = p.communicate()[0].strip()
        expected = ("\xa2" + os.linesep).encode("cp424")
        self.assertEqual(out, expected)

        env["PYTHONIOENCODING"] = "ascii:replace"
        p = subprocess.Popen([sys.executable, "-c", 'print(chr(0xa2))'],
                             stdout = subprocess.PIPE, env=env)
        out = p.communicate()[0].strip()
        self.assertEqual(out, b'?')

        env["PYTHONIOENCODING"] = "ascii"
        p = subprocess.Popen([sys.executable, "-c", 'print(chr(0xa2))'],
                             stdout=subprocess.PIPE, stderr=subprocess.PIPE,
                             env=env)
        out, err = p.communicate()
        self.assertEqual(out, b'')
        self.assertIn(b'UnicodeEncodeError:', err)
        self.assertIn(rb"'\xa2'", err)

        env["PYTHONIOENCODING"] = "ascii:"
        p = subprocess.Popen([sys.executable, "-c", 'print(chr(0xa2))'],
                             stdout=subprocess.PIPE, stderr=subprocess.PIPE,
                             env=env)
        out, err = p.communicate()
        self.assertEqual(out, b'')
        self.assertIn(b'UnicodeEncodeError:', err)
        self.assertIn(rb"'\xa2'", err)

        env["PYTHONIOENCODING"] = ":surrogateescape"
        p = subprocess.Popen([sys.executable, "-c", 'print(chr(0xdcbd))'],
                             stdout=subprocess.PIPE, env=env)
        out = p.communicate()[0].strip()
        self.assertEqual(out, b'\xbd')

    @unittest.skipUnless(os_helper.FS_NONASCII,
                         'requires OS support of non-ASCII encodings')
    @unittest.skipUnless(sys.getfilesystemencoding() == locale.getpreferredencoding(False),
                         'requires FS encoding to match locale')
    @support.requires_subprocess()
    def test_ioencoding_nonascii(self):
        env = dict(os.environ)

        env["PYTHONIOENCODING"] = ""
        p = subprocess.Popen([sys.executable, "-c",
                                'print(%a)' % os_helper.FS_NONASCII],
                                stdout=subprocess.PIPE, env=env)
        out = p.communicate()[0].strip()
        self.assertEqual(out, os.fsencode(os_helper.FS_NONASCII))

    @unittest.skipIf(sys.base_prefix != sys.prefix,
                     'Test is not venv-compatible')
    @support.requires_subprocess()
    def test_executable(self):
        # sys.executable should be absolute
        self.assertEqual(os.path.abspath(sys.executable), sys.executable)

        # Issue #7774: Ensure that sys.executable is an empty string if argv[0]
        # has been set to a non existent program name and Python is unable to
        # retrieve the real program name

        # For a normal installation, it should work without 'cwd'
        # argument. For test runs in the build directory, see #7774.
        python_dir = os.path.dirname(os.path.realpath(sys.executable))
        p = subprocess.Popen(
            ["nonexistent", "-c",
             'import sys; print(sys.executable.encode("ascii", "backslashreplace"))'],
            executable=sys.executable, stdout=subprocess.PIPE, cwd=python_dir)
        stdout = p.communicate()[0]
        executable = stdout.strip().decode("ASCII")
        p.wait()
        self.assertIn(executable, ["b''", repr(sys.executable.encode("ascii", "backslashreplace"))])

    def check_fsencoding(self, fs_encoding, expected=None):
        self.assertIsNotNone(fs_encoding)
        codecs.lookup(fs_encoding)
        if expected:
            self.assertEqual(fs_encoding, expected)

    def test_getfilesystemencoding(self):
        fs_encoding = sys.getfilesystemencoding()
        if sys.platform == 'darwin':
            expected = 'utf-8'
        else:
            expected = None
        self.check_fsencoding(fs_encoding, expected)

    def c_locale_get_error_handler(self, locale, isolated=False, encoding=None):
        # Force the POSIX locale
        env = os.environ.copy()
        env["LC_ALL"] = locale
        env["PYTHONCOERCECLOCALE"] = "0"
        code = '\n'.join((
            'import sys',
            'def dump(name):',
            '    std = getattr(sys, name)',
            '    print("%s: %s" % (name, std.errors))',
            'dump("stdin")',
            'dump("stdout")',
            'dump("stderr")',
        ))
        args = [sys.executable, "-X", "utf8=0", "-c", code]
        if isolated:
            args.append("-I")
        if encoding is not None:
            env['PYTHONIOENCODING'] = encoding
        else:
            env.pop('PYTHONIOENCODING', None)
        p = subprocess.Popen(args,
                              stdout=subprocess.PIPE,
                              stderr=subprocess.STDOUT,
                              env=env,
                              universal_newlines=True)
        stdout, stderr = p.communicate()
        return stdout

    def check_locale_surrogateescape(self, locale):
        out = self.c_locale_get_error_handler(locale, isolated=True)
        self.assertEqual(out,
                         'stdin: surrogateescape\n'
                         'stdout: surrogateescape\n'
                         'stderr: backslashreplace\n')

        # replace the default error handler
        out = self.c_locale_get_error_handler(locale, encoding=':ignore')
        self.assertEqual(out,
                         'stdin: ignore\n'
                         'stdout: ignore\n'
                         'stderr: backslashreplace\n')

        # force the encoding
        out = self.c_locale_get_error_handler(locale, encoding='iso8859-1')
        self.assertEqual(out,
                         'stdin: strict\n'
                         'stdout: strict\n'
                         'stderr: backslashreplace\n')
        out = self.c_locale_get_error_handler(locale, encoding='iso8859-1:')
        self.assertEqual(out,
                         'stdin: strict\n'
                         'stdout: strict\n'
                         'stderr: backslashreplace\n')

        # have no any effect
        out = self.c_locale_get_error_handler(locale, encoding=':')
        self.assertEqual(out,
                         'stdin: surrogateescape\n'
                         'stdout: surrogateescape\n'
                         'stderr: backslashreplace\n')
        out = self.c_locale_get_error_handler(locale, encoding='')
        self.assertEqual(out,
                         'stdin: surrogateescape\n'
                         'stdout: surrogateescape\n'
                         'stderr: backslashreplace\n')

    @support.requires_subprocess()
    def test_c_locale_surrogateescape(self):
        self.check_locale_surrogateescape('C')

    @support.requires_subprocess()
    def test_posix_locale_surrogateescape(self):
        self.check_locale_surrogateescape('POSIX')

    def test_implementation(self):
        # This test applies to all implementations equally.

        levels = {'alpha': 0xA, 'beta': 0xB, 'candidate': 0xC, 'final': 0xF}

        self.assertHasAttr(sys.implementation, 'name')
        self.assertHasAttr(sys.implementation, 'version')
        self.assertHasAttr(sys.implementation, 'hexversion')
        self.assertHasAttr(sys.implementation, 'cache_tag')
        self.assertHasAttr(sys.implementation, 'supports_isolated_interpreters')

        version = sys.implementation.version
        self.assertEqual(version[:2], (version.major, version.minor))

        hexversion = (version.major << 24 | version.minor << 16 |
                      version.micro << 8 | levels[version.releaselevel] << 4 |
                      version.serial << 0)
        self.assertEqual(sys.implementation.hexversion, hexversion)

        # PEP 421 requires that .name be lower case.
        self.assertEqual(sys.implementation.name,
                         sys.implementation.name.lower())

        # https://peps.python.org/pep-0734
        sii = sys.implementation.supports_isolated_interpreters
        self.assertIsInstance(sii, bool)
        if test.support.check_impl_detail(cpython=True):
            if test.support.is_emscripten or test.support.is_wasi:
                self.assertFalse(sii)
            else:
                self.assertTrue(sii)

    @test.support.cpython_only
    def test_debugmallocstats(self):
        # Test sys._debugmallocstats()
        from test.support.script_helper import assert_python_ok
        args = ['-c', 'import sys; sys._debugmallocstats()']
        ret, out, err = assert_python_ok(*args)

        # Output of sys._debugmallocstats() depends on configure flags.
        # The sysconfig vars are not available on Windows.
        if sys.platform != "win32":
            with_pymalloc = sysconfig.get_config_var("WITH_PYMALLOC")
            with_sanitizer = support.check_sanitizer(address=True, memory=True)
            self.assertIn(b"free PyDictObjects", err)
            # ASan and MSan builds default to malloc, even with pymalloc.
            if with_pymalloc and not with_sanitizer:
                self.assertIn(b'Small block threshold', err)

        # The function has no parameter
        self.assertRaises(TypeError, sys._debugmallocstats, True)

    @unittest.skipUnless(hasattr(sys, "getallocatedblocks"),
                         "sys.getallocatedblocks unavailable on this build")
    def test_getallocatedblocks(self):
        try:
            import _testinternalcapi
        except ImportError:
            with_pymalloc = support.with_pymalloc()
        else:
            try:
                alloc_name = _testinternalcapi.pymem_getallocatorsname()
            except RuntimeError as exc:
                # "cannot get allocators name" (ex: tracemalloc is used)
                with_pymalloc = True
            else:
                with_pymalloc = (alloc_name in ('pymalloc', 'pymalloc_debug'))

        # Some sanity checks
        a = sys.getallocatedblocks()
        self.assertIs(type(a), int)
        if with_pymalloc:
            self.assertGreater(a, 0)
        else:
            # When WITH_PYMALLOC isn't available, we don't know anything
            # about the underlying implementation: the function might
            # return 0 or something greater.
            self.assertGreaterEqual(a, 0)
        gc.collect()
        b = sys.getallocatedblocks()
        self.assertLessEqual(b, a)
        try:
            # The reported blocks will include immortalized strings, but the
            # total ref count will not. This will sanity check that among all
            # other objects (those eligible for garbage collection) there
            # are more references being tracked than allocated blocks.
            interned_immortal = sys.getunicodeinternedsize(_only_immortal=True)
            self.assertLess(a - interned_immortal, sys.gettotalrefcount())
        except AttributeError:
            # gettotalrefcount() not available
            pass
        gc.collect()
        c = sys.getallocatedblocks()
        self.assertIn(c, range(b - 50, b + 50))

    def test_is_gil_enabled(self):
        if support.Py_GIL_DISABLED:
            self.assertIs(type(sys._is_gil_enabled()), bool)
        else:
            self.assertTrue(sys._is_gil_enabled())

    def test_is_finalizing(self):
        self.assertIs(sys.is_finalizing(), False)
        # Don't use the atexit module because _Py_Finalizing is only set
        # after calling atexit callbacks
        code = """if 1:
            import sys

            class AtExit:
                is_finalizing = sys.is_finalizing
                print = print

                def __del__(self):
                    self.print(self.is_finalizing(), flush=True)

            # Keep a reference in the __main__ module namespace, so the
            # AtExit destructor will be called at Python exit
            ref = AtExit()
        """
        rc, stdout, stderr = assert_python_ok('-c', code)
        self.assertEqual(stdout.rstrip(), b'True')

    def test_issue20602(self):
        # sys.flags and sys.float_info were wiped during shutdown.
        code = """if 1:
            import sys
            class A:
                def __del__(self, sys=sys):
                    print(sys.flags)
                    print(sys.float_info)
            a = A()
            """
        rc, out, err = assert_python_ok('-c', code)
        out = out.splitlines()
        self.assertIn(b'sys.flags', out[0])
        self.assertIn(b'sys.float_info', out[1])

    def test_sys_ignores_cleaning_up_user_data(self):
        code = """if 1:
            import struct, sys

            class C:
                def __init__(self):
                    self.pack = struct.pack
                def __del__(self):
                    self.pack('I', -42)

            sys.x = C()
            """
        rc, stdout, stderr = assert_python_ok('-c', code)
        self.assertEqual(rc, 0)
        self.assertEqual(stdout.rstrip(), b"")
        self.assertEqual(stderr.rstrip(), b"")

    @unittest.skipUnless(sys.platform == "android", "Android only")
    def test_getandroidapilevel(self):
        level = sys.getandroidapilevel()
        self.assertIsInstance(level, int)
        self.assertGreater(level, 0)

    @force_not_colorized
    @support.requires_subprocess()
    def test_sys_tracebacklimit(self):
        code = """if 1:
            import sys
            def f1():
                1 / 0
            def f2():
                f1()
            sys.tracebacklimit = %r
            f2()
        """
        def check(tracebacklimit, expected):
            p = subprocess.Popen([sys.executable, '-c', code % tracebacklimit],
                                 stderr=subprocess.PIPE)
            out = p.communicate()[1]
            self.assertEqual(out.splitlines(), expected)

        traceback = [
            b'Traceback (most recent call last):',
            b'  File "<string>", line 8, in <module>',
            b'    f2()',
            b'    ~~^^',
            b'  File "<string>", line 6, in f2',
            b'    f1()',
            b'    ~~^^',
            b'  File "<string>", line 4, in f1',
            b'    1 / 0',
            b'    ~~^~~',
            b'ZeroDivisionError: division by zero'
        ]
        check(10, traceback)
        check(3, traceback)
        check(2, traceback[:1] + traceback[4:])
        check(1, traceback[:1] + traceback[7:])
        check(0, [traceback[-1]])
        check(-1, [traceback[-1]])
        check(1<<1000, traceback)
        check(-1<<1000, [traceback[-1]])
        check(None, traceback)

    def test_no_duplicates_in_meta_path(self):
        self.assertEqual(len(sys.meta_path), len(set(sys.meta_path)))

    @support.requires_subprocess()
    def test_orig_argv(self):
        code = textwrap.dedent('''
            import sys
            print(sys.argv)
            print(sys.orig_argv)
        ''')
        args = [sys.executable, '-I', '-X', 'utf8', '-c', code, 'arg']
        proc = subprocess.run(args, check=True, capture_output=True, text=True)
        expected = [
            repr(['-c', 'arg']),  # sys.argv
            repr(args),  # sys.orig_argv
        ]
        self.assertEqual(proc.stdout.rstrip().splitlines(), expected,
                         proc)

    def test_module_names(self):
        self.assertIsInstance(sys.stdlib_module_names, frozenset)
        for name in sys.stdlib_module_names:
            self.assertIsInstance(name, str)

    @unittest.skipUnless(hasattr(sys, '_stdlib_dir'), 'need sys._stdlib_dir')
    def test_stdlib_dir(self):
        os = import_helper.import_fresh_module('os')
        marker = getattr(os, '__file__', None)
        if marker and not os.path.exists(marker):
            marker = None
        expected = os.path.dirname(marker) if marker else None
        self.assertEqual(os.path.normpath(sys._stdlib_dir),
                         os.path.normpath(expected))

    @unittest.skipUnless(hasattr(sys, 'getobjects'), 'need sys.getobjects()')
    def test_getobjects(self):
        # sys.getobjects(0)
        all_objects = sys.getobjects(0)
        self.assertIsInstance(all_objects, list)
        self.assertGreater(len(all_objects), 0)

        # sys.getobjects(0, MyType)
        class MyType:
            pass
        size = 100
        my_objects = [MyType() for _ in range(size)]
        get_objects = sys.getobjects(0, MyType)
        self.assertEqual(len(get_objects), size)
        for obj in get_objects:
            self.assertIsInstance(obj, MyType)

        # sys.getobjects(3, MyType)
        get_objects = sys.getobjects(3, MyType)
        self.assertEqual(len(get_objects), 3)

    @unittest.skipUnless(hasattr(sys, '_stats_on'), 'need Py_STATS build')
    def test_pystats(self):
        # Call the functions, just check that they don't crash
        # Cannot save/restore state.
        sys._stats_on()
        sys._stats_off()
        sys._stats_clear()
        sys._stats_dump()

    @test.support.cpython_only
    @unittest.skipUnless(hasattr(sys, 'abiflags'), 'need sys.abiflags')
    def test_disable_gil_abi(self):
        self.assertEqual('t' in sys.abiflags, support.Py_GIL_DISABLED)

    def test_int_max_str_digits(self):
        old_limit = sys.get_int_max_str_digits()
        self.assertIsInstance(old_limit, int)
        self.assertGreaterEqual(old_limit, 0)
        self.addCleanup(sys.set_int_max_str_digits, old_limit)

        sys.set_int_max_str_digits(0)
        self.assertEqual(sys.get_int_max_str_digits(), 0)

        sys.set_int_max_str_digits(2_048)
        self.assertEqual(sys.get_int_max_str_digits(), 2_048)

        with self.assertRaises(ValueError):
            # the minimum is 640 digits
            sys.set_int_max_str_digits(5)
        with self.assertRaises(ValueError):
            sys.set_int_max_str_digits(-2)
        with self.assertRaises(TypeError):
            sys.set_int_max_str_digits(2_048.0)

    @test.support.cpython_only
    def test_is_immortal(self):
        is_immortal = sys._is_immortal

        # Singletons
        self.assertTrue(is_immortal(None))
        self.assertTrue(is_immortal(False))
        self.assertTrue(is_immortal(True))
        self.assertTrue(is_immortal(0))
        self.assertTrue(is_immortal(b''))
        self.assertTrue(is_immortal(''))
        self.assertTrue(is_immortal(b'x'))
        self.assertTrue(is_immortal('x'))
        self.assertTrue(is_immortal(()))

        # Static types
        self.assertTrue(is_immortal(int))
        self.assertTrue(is_immortal(dict))

        # Test some mortal objects
        class PythonType:
            pass
        self.assertFalse(is_immortal([1, 2, 3]))
        self.assertFalse(is_immortal({'key': 5}))
        self.assertFalse(is_immortal(object()))
        self.assertFalse(is_immortal(PythonType))
        self.assertFalse(is_immortal(2 ** 100))
        # Use encode/decode to get a fresh object
        self.assertFalse(is_immortal(b'abc'.decode()))
        self.assertFalse(is_immortal('abc'.encode()))


@test.support.cpython_only
@test.support.force_not_colorized_test_class
class UnraisableHookTest(unittest.TestCase):
    def test_original_unraisablehook(self):
        _testcapi = import_helper.import_module('_testcapi')
        from _testcapi import err_writeunraisable, err_formatunraisable
        obj = hex

        with support.swap_attr(sys, 'unraisablehook',
                                    sys.__unraisablehook__):
            with support.captured_stderr() as stderr:
                err_writeunraisable(ValueError(42), obj)
            lines = stderr.getvalue().splitlines()
            self.assertEqual(lines[0], f'Exception ignored in: {obj!r}')
            self.assertEqual(lines[1], 'Traceback (most recent call last):')
            self.assertEqual(lines[-1], 'ValueError: 42')

            with support.captured_stderr() as stderr:
                err_writeunraisable(ValueError(42), None)
            lines = stderr.getvalue().splitlines()
            self.assertEqual(lines[0], 'Traceback (most recent call last):')
            self.assertEqual(lines[-1], 'ValueError: 42')

            with support.captured_stderr() as stderr:
                err_formatunraisable(ValueError(42), 'Error in %R', obj)
            lines = stderr.getvalue().splitlines()
            self.assertEqual(lines[0], f'Error in {obj!r}:')
            self.assertEqual(lines[1], 'Traceback (most recent call last):')
            self.assertEqual(lines[-1], 'ValueError: 42')

            with support.captured_stderr() as stderr:
                err_formatunraisable(ValueError(42), None)
            lines = stderr.getvalue().splitlines()
            self.assertEqual(lines[0], 'Traceback (most recent call last):')
            self.assertEqual(lines[-1], 'ValueError: 42')

    def test_original_unraisablehook_err(self):
        # bpo-22836: PyErr_WriteUnraisable() should give sensible reports
        class BrokenDel:
            def __del__(self):
                exc = ValueError("del is broken")
                # The following line is included in the traceback report:
                raise exc

        class BrokenStrException(Exception):
            def __str__(self):
                raise Exception("str() is broken")

        class BrokenExceptionDel:
            def __del__(self):
                exc = BrokenStrException()
                # The following line is included in the traceback report:
                raise exc

        for test_class in (BrokenDel, BrokenExceptionDel):
            with self.subTest(test_class):
                obj = test_class()
                with test.support.captured_stderr() as stderr, \
                     test.support.swap_attr(sys, 'unraisablehook',
                                            sys.__unraisablehook__):
                    # Trigger obj.__del__()
                    del obj

                report = stderr.getvalue()
                self.assertIn("Exception ignored", report)
                self.assertIn(test_class.__del__.__qualname__, report)
                self.assertIn("test_sys.py", report)
                self.assertIn("raise exc", report)
                if test_class is BrokenExceptionDel:
                    self.assertIn("BrokenStrException", report)
                    self.assertIn("<exception str() failed>", report)
                else:
                    self.assertIn("ValueError", report)
                    self.assertIn("del is broken", report)
                self.assertEndsWith(report, "\n")

    def test_original_unraisablehook_exception_qualname(self):
        # See bpo-41031, bpo-45083.
        # Check that the exception is printed with its qualified name
        # rather than just classname, and the module names appears
        # unless it is one of the hard-coded exclusions.
        _testcapi = import_helper.import_module('_testcapi')
        from _testcapi import err_writeunraisable
        class A:
            class B:
                class X(Exception):
                    pass

        for moduleName in 'builtins', '__main__', 'some_module':
            with self.subTest(moduleName=moduleName):
                A.B.X.__module__ = moduleName
                with test.support.captured_stderr() as stderr, test.support.swap_attr(
                    sys, 'unraisablehook', sys.__unraisablehook__
                ):
                    err_writeunraisable(A.B.X(), "obj")
                report = stderr.getvalue()
                self.assertIn(A.B.X.__qualname__, report)
                if moduleName in ['builtins', '__main__']:
                    self.assertNotIn(moduleName + '.', report)
                else:
                    self.assertIn(moduleName + '.', report)

    def test_original_unraisablehook_wrong_type(self):
        exc = ValueError(42)
        with test.support.swap_attr(sys, 'unraisablehook',
                                    sys.__unraisablehook__):
            with self.assertRaises(TypeError):
                sys.unraisablehook(exc)

    def test_custom_unraisablehook(self):
        _testcapi = import_helper.import_module('_testcapi')
        from _testcapi import err_writeunraisable, err_formatunraisable
        hook_args = None

        def hook_func(args):
            nonlocal hook_args
            hook_args = args

        obj = hex
        try:
            with test.support.swap_attr(sys, 'unraisablehook', hook_func):
                exc = ValueError(42)
                err_writeunraisable(exc, obj)
                self.assertIs(hook_args.exc_type, type(exc))
                self.assertIs(hook_args.exc_value, exc)
                self.assertIs(hook_args.exc_traceback, exc.__traceback__)
                self.assertIsNone(hook_args.err_msg)
                self.assertEqual(hook_args.object, obj)

                err_formatunraisable(exc, "custom hook %R", obj)
                self.assertIs(hook_args.exc_type, type(exc))
                self.assertIs(hook_args.exc_value, exc)
                self.assertIs(hook_args.exc_traceback, exc.__traceback__)
                self.assertEqual(hook_args.err_msg, f'custom hook {obj!r}')
                self.assertIsNone(hook_args.object)
        finally:
            # expected and hook_args contain an exception: break reference cycle
            expected = None
            hook_args = None

    def test_custom_unraisablehook_fail(self):
        _testcapi = import_helper.import_module('_testcapi')
        from _testcapi import err_writeunraisable

        def hook_func(*args):
            raise Exception("hook_func failed")

        with test.support.captured_output("stderr") as stderr:
            with test.support.swap_attr(sys, 'unraisablehook', hook_func):
                err_writeunraisable(ValueError(42), "custom hook fail")

        err = stderr.getvalue()
        self.assertIn(f'Exception ignored in sys.unraisablehook: '
                      f'{hook_func!r}\n',
                      err)
        self.assertIn('Traceback (most recent call last):\n', err)
        self.assertIn('Exception: hook_func failed\n', err)


@test.support.cpython_only
class SizeofTest(unittest.TestCase):

    def setUp(self):
        self.P = struct.calcsize('P')
        self.longdigit = sys.int_info.sizeof_digit
        _testinternalcapi = import_helper.import_module("_testinternalcapi")
        self.gc_headsize = _testinternalcapi.SIZEOF_PYGC_HEAD
        self.managed_pre_header_size = _testinternalcapi.SIZEOF_MANAGED_PRE_HEADER

    check_sizeof = test.support.check_sizeof

    def test_gc_head_size(self):
        # Check that the gc header size is added to objects tracked by the gc.
        vsize = test.support.calcvobjsize
        gc_header_size = self.gc_headsize
        # bool objects are not gc tracked
        self.assertEqual(sys.getsizeof(True), vsize('') + self.longdigit)
        # but lists are
        self.assertEqual(sys.getsizeof([]), vsize('Pn') + gc_header_size)

    def test_errors(self):
        class BadSizeof:
            def __sizeof__(self):
                raise ValueError
        self.assertRaises(ValueError, sys.getsizeof, BadSizeof())

        class InvalidSizeof:
            def __sizeof__(self):
                return None
        self.assertRaises(TypeError, sys.getsizeof, InvalidSizeof())
        sentinel = ["sentinel"]
        self.assertIs(sys.getsizeof(InvalidSizeof(), sentinel), sentinel)

        class FloatSizeof:
            def __sizeof__(self):
                return 4.5
        self.assertRaises(TypeError, sys.getsizeof, FloatSizeof())
        self.assertIs(sys.getsizeof(FloatSizeof(), sentinel), sentinel)

        class OverflowSizeof(int):
            def __sizeof__(self):
                return int(self)
        self.assertEqual(sys.getsizeof(OverflowSizeof(sys.maxsize)),
                         sys.maxsize + self.gc_headsize + self.managed_pre_header_size)
        with self.assertRaises(OverflowError):
            sys.getsizeof(OverflowSizeof(sys.maxsize + 1))
        with self.assertRaises(ValueError):
            sys.getsizeof(OverflowSizeof(-1))
        with self.assertRaises((ValueError, OverflowError)):
            sys.getsizeof(OverflowSizeof(-sys.maxsize - 1))

    def test_default(self):
        size = test.support.calcvobjsize
        self.assertEqual(sys.getsizeof(True), size('') + self.longdigit)
        self.assertEqual(sys.getsizeof(True, -1), size('') + self.longdigit)

    def test_objecttypes(self):
        # check all types defined in Objects/
        calcsize = struct.calcsize
        size = test.support.calcobjsize
        vsize = test.support.calcvobjsize
        check = self.check_sizeof
        # bool
        check(True, vsize('') + self.longdigit)
        check(False, vsize('') + self.longdigit)
        # buffer
        # XXX
        # builtin_function_or_method
        check(len, size('5P'))
        # bytearray
        samples = [b'', b'u'*100000]
        for sample in samples:
            x = bytearray(sample)
            check(x, vsize('n2PiP') + x.__alloc__())
        # bytearray_iterator
        check(iter(bytearray()), size('nP'))
        # bytes
        check(b'', vsize('n') + 1)
        check(b'x' * 10, vsize('n') + 11)
        # cell
        def get_cell():
            x = 42
            def inner():
                return x
            return inner
        check(get_cell().__closure__[0], size('P'))
        # code
        def check_code_size(a, expected_size):
            self.assertGreaterEqual(sys.getsizeof(a), expected_size)
        check_code_size(get_cell().__code__, size('6i13P'))
        check_code_size(get_cell.__code__, size('6i13P'))
        def get_cell2(x):
            def inner():
                return x
            return inner
        check_code_size(get_cell2.__code__, size('6i13P') + calcsize('n'))
        # complex
        check(complex(0,1), size('2d'))
        # method_descriptor (descriptor object)
        check(str.lower, size('3PPP'))
        # classmethod_descriptor (descriptor object)
        # XXX
        # member_descriptor (descriptor object)
        import datetime
        check(datetime.timedelta.days, size('3PP'))
        # getset_descriptor (descriptor object)
        import collections
        check(collections.defaultdict.default_factory, size('3PP'))
        # wrapper_descriptor (descriptor object)
        check(int.__add__, size('3P2P'))
        # method-wrapper (descriptor object)
        check({}.__iter__, size('2P'))
        # empty dict
        check({}, size('nQ2P'))
        # dict (string key)
        check({"a": 1}, size('nQ2P') + calcsize(DICT_KEY_STRUCT_FORMAT) + 8 + (8*2//3)*calcsize('2P'))
        longdict = {str(i): i for i in range(8)}
        check(longdict, size('nQ2P') + calcsize(DICT_KEY_STRUCT_FORMAT) + 16 + (16*2//3)*calcsize('2P'))
        # dict (non-string key)
        check({1: 1}, size('nQ2P') + calcsize(DICT_KEY_STRUCT_FORMAT) + 8 + (8*2//3)*calcsize('n2P'))
        longdict = {1:1, 2:2, 3:3, 4:4, 5:5, 6:6, 7:7, 8:8}
        check(longdict, size('nQ2P') + calcsize(DICT_KEY_STRUCT_FORMAT) + 16 + (16*2//3)*calcsize('n2P'))
        # dictionary-keyview
        check({}.keys(), size('P'))
        # dictionary-valueview
        check({}.values(), size('P'))
        # dictionary-itemview
        check({}.items(), size('P'))
        # dictionary iterator
        check(iter({}), size('P2nPn'))
        # dictionary-keyiterator
        check(iter({}.keys()), size('P2nPn'))
        # dictionary-valueiterator
        check(iter({}.values()), size('P2nPn'))
        # dictionary-itemiterator
        check(iter({}.items()), size('P2nPn'))
        # dictproxy
        class C(object): pass
        check(C.__dict__, size('P'))
        # BaseException
        check(BaseException(), size('6Pb'))
        # UnicodeEncodeError
        check(UnicodeEncodeError("", "", 0, 0, ""), size('6Pb 2P2nP'))
        # UnicodeDecodeError
        check(UnicodeDecodeError("", b"", 0, 0, ""), size('6Pb 2P2nP'))
        # UnicodeTranslateError
        check(UnicodeTranslateError("", 0, 1, ""), size('6Pb 2P2nP'))
        # ellipses
        check(Ellipsis, size(''))
        # EncodingMap
        import codecs, encodings.iso8859_3
        x = codecs.charmap_build(encodings.iso8859_3.decoding_table)
        check(x, size('32B2iB'))
        # enumerate
        check(enumerate([]), size('n4P'))
        # reverse
        check(reversed(''), size('nP'))
        # float
        check(float(0), size('d'))
        # sys.floatinfo
        check(sys.float_info, self.P + vsize('') + self.P * len(sys.float_info))
        # frame
        def func():
            return sys._getframe()
        x = func()
        if support.Py_GIL_DISABLED:
            INTERPRETER_FRAME = '9PihcP'
        else:
            INTERPRETER_FRAME = '9PhcP'
        check(x, size('3PiccPPPP' + INTERPRETER_FRAME + 'P'))
        # function
        def func(): pass
        check(func, size('16Pi'))
        class c():
            @staticmethod
            def foo():
                pass
            @classmethod
            def bar(cls):
                pass
            # staticmethod
            check(foo, size('PP'))
            # classmethod
            check(bar, size('PP'))
        # generator
        def get_gen(): yield 1
        check(get_gen(), size('6P4c' + INTERPRETER_FRAME + 'P'))
        # iterator
        check(iter('abc'), size('lP'))
        # callable-iterator
        import re
        check(re.finditer('',''), size('3P'))
        # list
        check(list([]), vsize('Pn'))
        check(list([1]), vsize('Pn') + 2*self.P)
        check(list([1, 2]), vsize('Pn') + 2*self.P)
        check(list([1, 2, 3]), vsize('Pn') + 4*self.P)
        # sortwrapper (list)
        # XXX
        # cmpwrapper (list)
        # XXX
        # listiterator (list)
        check(iter([]), size('lP'))
        # listreverseiterator (list)
        check(reversed([]), size('nP'))
        # int
        check(0, vsize('') + self.longdigit)
        check(1, vsize('') + self.longdigit)
        check(-1, vsize('') + self.longdigit)
        PyLong_BASE = 2**sys.int_info.bits_per_digit
        check(int(PyLong_BASE), vsize('') + 2*self.longdigit)
        check(int(PyLong_BASE**2-1), vsize('') + 2*self.longdigit)
        check(int(PyLong_BASE**2), vsize('') + 3*self.longdigit)
        # module
        if support.Py_GIL_DISABLED:
            md_gil = '?'
        else:
            md_gil = ''
        check(unittest, size('PPPP?' + md_gil + 'NPPPPP'))
        # None
        check(None, size(''))
        # NotImplementedType
        check(NotImplemented, size(''))
        # object
        check(object(), size(''))
        # property (descriptor object)
        class C(object):
            def getx(self): return self.__x
            def setx(self, value): self.__x = value
            def delx(self): del self.__x
            x = property(getx, setx, delx, "")
            check(x, size('5Pi'))
        # PyCapsule
        try:
            import _datetime
        except ModuleNotFoundError:
            pass
        else:
            check(_datetime.datetime_CAPI, size('6P'))
        # rangeiterator
        check(iter(range(1)), size('3l'))
        check(iter(range(2**65)), size('3P'))
        # reverse
        check(reversed(''), size('nP'))
        # range
        check(range(1), size('4P'))
        check(range(66000), size('4P'))
        # set
        # frozenset
        PySet_MINSIZE = 8
        samples = [[], range(10), range(50)]
        s = size('3nP' + PySet_MINSIZE*'nP' + '2nP')
        for sample in samples:
            minused = len(sample)
            if minused == 0: tmp = 1
            # the computation of minused is actually a bit more complicated
            # but this suffices for the sizeof test
            minused = minused*2
            newsize = PySet_MINSIZE
            while newsize <= minused:
                newsize = newsize << 1
            if newsize <= 8:
                check(set(sample), s)
                check(frozenset(sample), s)
            else:
                check(set(sample), s + newsize*calcsize('nP'))
                check(frozenset(sample), s + newsize*calcsize('nP'))
        # setiterator
        check(iter(set()), size('P3n'))
        # slice
        check(slice(0), size('3P'))
        # super
        check(super(int), size('3P'))
        # tuple
        check((), vsize('') + self.P)
        check((1,2,3), vsize('') + self.P + 3*self.P)
        # type
        # static type: PyTypeObject
        fmt = 'P2nPI13Pl4Pn9Pn12PI2PcP'
        s = vsize(fmt)
        check(int, s)
        typeid = 'n' if support.Py_GIL_DISABLED else ''
        # class
        s = vsize(fmt +                 # PyTypeObject
                  '4P'                  # PyAsyncMethods
                  '36P'                 # PyNumberMethods
                  '3P'                  # PyMappingMethods
                  '10P'                 # PySequenceMethods
                  '2P'                  # PyBufferProcs
                  '7P'
                  '1PIP'                # Specializer cache
                  + typeid              # heap type id (free-threaded only)
                  )
        class newstyleclass(object): pass
        # Separate block for PyDictKeysObject with 8 keys and 5 entries
        check(newstyleclass, s + calcsize(DICT_KEY_STRUCT_FORMAT) + 64 + 42*calcsize("2P"))
        # dict with shared keys
        [newstyleclass() for _ in range(100)]
        check(newstyleclass().__dict__, size('nQ2P') + self.P)
        o = newstyleclass()
        o.a = o.b = o.c = o.d = o.e = o.f = o.g = o.h = 1
        # Separate block for PyDictKeysObject with 16 keys and 10 entries
        check(newstyleclass, s + calcsize(DICT_KEY_STRUCT_FORMAT) + 64 + 42*calcsize("2P"))
        # dict with shared keys
        check(newstyleclass().__dict__, size('nQ2P') + self.P)
        # unicode
        # each tuple contains a string and its expected character size
        # don't put any static strings here, as they may contain
        # wchar_t or UTF-8 representations
        samples = ['1'*100, '\xff'*50,
                   '\u0100'*40, '\uffff'*100,
                   '\U00010000'*30, '\U0010ffff'*100]
        # also update field definitions in test_unicode.test_raiseMemError
        asciifields = "nnb"
        compactfields = asciifields + "nP"
        unicodefields = compactfields + "P"
        for s in samples:
            maxchar = ord(max(s))
            if maxchar < 128:
                L = size(asciifields) + len(s) + 1
            elif maxchar < 256:
                L = size(compactfields) + len(s) + 1
            elif maxchar < 65536:
                L = size(compactfields) + 2*(len(s) + 1)
            else:
                L = size(compactfields) + 4*(len(s) + 1)
            check(s, L)
        # verify that the UTF-8 size is accounted for
        s = chr(0x4000)   # 4 bytes canonical representation
        check(s, size(compactfields) + 4)
        # compile() will trigger the generation of the UTF-8
        # representation as a side effect
        compile(s, "<stdin>", "eval")
        check(s, size(compactfields) + 4 + 4)
        # TODO: add check that forces the presence of wchar_t representation
        # TODO: add check that forces layout of unicodefields
        # weakref
        import weakref
        if support.Py_GIL_DISABLED:
            expected = size('2Pn4P')
        else:
            expected = size('2Pn3P')
        check(weakref.ref(int), expected)
        # weakproxy
        # XXX
        # weakcallableproxy
        check(weakref.proxy(int), expected)

    def check_slots(self, obj, base, extra):
        expected = sys.getsizeof(base) + struct.calcsize(extra)
        if gc.is_tracked(obj) and not gc.is_tracked(base):
            expected += self.gc_headsize
        self.assertEqual(sys.getsizeof(obj), expected)

    def test_slots(self):
        # check all subclassable types defined in Objects/ that allow
        # non-empty __slots__
        check = self.check_slots
        class BA(bytearray):
            __slots__ = 'a', 'b', 'c'
        check(BA(), bytearray(), '3P')
        class D(dict):
            __slots__ = 'a', 'b', 'c'
        check(D(x=[]), {'x': []}, '3P')
        class L(list):
            __slots__ = 'a', 'b', 'c'
        check(L(), [], '3P')
        class S(set):
            __slots__ = 'a', 'b', 'c'
        check(S(), set(), '3P')
        class FS(frozenset):
            __slots__ = 'a', 'b', 'c'

        class mytuple(tuple):
            pass
        check(FS([mytuple()]), frozenset([mytuple()]), '3P')
        from collections import OrderedDict
        class OD(OrderedDict):
            __slots__ = 'a', 'b', 'c'
        check(OD(x=[]), OrderedDict(x=[]), '3P')

    def test_pythontypes(self):
        # check all types defined in Python/
        size = test.support.calcobjsize
        vsize = test.support.calcvobjsize
        check = self.check_sizeof
        # _ast.AST
        import _ast
        check(_ast.Module(), size('3P'))
        try:
            raise TypeError
        except TypeError as e:
            tb = e.__traceback__
            # traceback
            if tb is not None:
                check(tb, size('2P2i'))
        # symtable entry
        # XXX
        # sys.flags
        # FIXME: The non_sequence_fields adjustment is for these flags:
        # - 'gil'
        # - 'thread_inherit_context'
        # - 'context_aware_warnings'
        # - 'lazy_imports'
        # Not needing to increment this every time we add a new field
        # per GH-122575 would be nice...
        # Q: What is the actual point of this sys.flags C size derived from PyStructSequence_Field array assertion?
        non_sequence_fields = 4
        check(sys.flags, vsize('') + self.P + self.P * (non_sequence_fields + len(sys.flags)))

    def test_asyncgen_hooks(self):
        old = sys.get_asyncgen_hooks()
        self.assertIsNone(old.firstiter)
        self.assertIsNone(old.finalizer)

        firstiter = lambda *a: None
        finalizer = lambda *a: None

        with self.assertRaises(TypeError):
            sys.set_asyncgen_hooks(firstiter=firstiter, finalizer="invalid")
        cur = sys.get_asyncgen_hooks()
        self.assertIsNone(cur.firstiter)
        self.assertIsNone(cur.finalizer)
        support.check_immutable_type(self, type(cur))

        # gh-118473
        with self.assertRaises(TypeError):
            sys.set_asyncgen_hooks(firstiter="invalid", finalizer=finalizer)
        cur = sys.get_asyncgen_hooks()
        self.assertIsNone(cur.firstiter)
        self.assertIsNone(cur.finalizer)

        sys.set_asyncgen_hooks(firstiter=firstiter)
        hooks = sys.get_asyncgen_hooks()
        self.assertIs(hooks.firstiter, firstiter)
        self.assertIs(hooks[0], firstiter)
        self.assertIs(hooks.finalizer, None)
        self.assertIs(hooks[1], None)

        sys.set_asyncgen_hooks(finalizer=finalizer)
        hooks = sys.get_asyncgen_hooks()
        self.assertIs(hooks.firstiter, firstiter)
        self.assertIs(hooks[0], firstiter)
        self.assertIs(hooks.finalizer, finalizer)
        self.assertIs(hooks[1], finalizer)

        sys.set_asyncgen_hooks(*old)
        cur = sys.get_asyncgen_hooks()
        self.assertIsNone(cur.firstiter)
        self.assertIsNone(cur.finalizer)

    def test_changing_sys_stderr_and_removing_reference(self):
        # If the default displayhook doesn't take a strong reference
        # to sys.stderr the following code can crash. See bpo-43660
        # for more details.
        code = textwrap.dedent('''
            import sys
            class MyStderr:
                def write(self, s):
                    sys.stderr = None
            sys.stderr = MyStderr()
            1/0
        ''')
        rc, out, err = assert_python_failure('-c', code)
        self.assertEqual(out, b"")
        self.assertEqual(err, b"")


@test.support.support_remote_exec_only
@test.support.cpython_only
class TestRemoteExec(unittest.TestCase):
    def tearDown(self):
        test.support.reap_children()

    def _run_remote_exec_test(self, script_code, python_args=None, env=None,
                              python_executable=None, prologue='',
                              after_ready=None,
                              script_path=os_helper.TESTFN + '_remote.py'):
        # Create the script that will be remotely executed
        self.addCleanup(os_helper.unlink, script_path)

        with open(script_path, 'w') as f:
            f.write(script_code)

        # Create and run the target process
        target = os_helper.TESTFN + '_target.py'
        self.addCleanup(os_helper.unlink, target)

        port = find_unused_port()

        with open(target, 'w') as f:
            f.write(f'''
import sys
import time
import socket

# Connect to the test process
sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
sock.connect(('localhost', {port}))

{prologue}

# Signal that the process is ready
sock.sendall(b"ready")

print("Target process running...")

# Wait for remote script to be executed
# (the execution will happen as the following
# code is processed as soon as the recv call
# unblocks)
sock.recv(1024)

# Do a bunch of work to give the remote script time to run
x = 0
for i in range(100):
    x += i

# Write confirmation back
sock.sendall(b"executed")
sock.close()
''')

        # Start the target process and capture its output
        if python_executable is None:
            python_executable = sys.executable

        cmd = [python_executable]
        if python_args:
            cmd.extend(python_args)
        cmd.append(target)

        # Create a socket server to communicate with the target process
        server_socket = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
        server_socket.bind(('localhost', port))
        server_socket.settimeout(SHORT_TIMEOUT)
        server_socket.listen(1)

        with subprocess.Popen(cmd,
                              stdout=subprocess.PIPE,
                              stderr=subprocess.PIPE,
                              env=env,
                              ) as proc:
            client_socket = None
            try:
                # Accept connection from target process
                client_socket, _ = server_socket.accept()
                server_socket.close()

                response = client_socket.recv(1024)
                self.assertEqual(response, b"ready")

                if after_ready is not None:
                    after_ready(proc)

                # Try remote exec on the target process
                sys.remote_exec(proc.pid, script_path)

                # Signal script to continue
                client_socket.sendall(b"continue")

                # Wait for execution confirmation
                response = client_socket.recv(1024)
                self.assertEqual(response, b"executed")

                # Return output for test verification
                stdout, stderr = proc.communicate(timeout=10.0)
                return proc.returncode, stdout, stderr
            except PermissionError:
                self.skipTest("Insufficient permissions to execute code in remote process")
            finally:
                if client_socket is not None:
                    client_socket.close()
                proc.kill()
                proc.terminate()
                proc.wait(timeout=SHORT_TIMEOUT)

    def _run_remote_exec_with_deleted_mapping(self, deleted_path, **kwargs):
        def delete_loaded_mapping(proc):
            os_helper.unlink(deleted_path)
            with open(f'/proc/{proc.pid}/maps', encoding='utf-8') as maps:
                self.assertIn(f'{deleted_path} (deleted)', maps.read())

        script = 'print("Remote script executed successfully!")'
        returncode, stdout, stderr = self._run_remote_exec_test(
            script, after_ready=delete_loaded_mapping, **kwargs)
        self.assertEqual(returncode, 0)
        self.assertIn(b"Remote script executed successfully!", stdout)
        self.assertEqual(stderr, b"")

    def test_remote_exec(self):
        """Test basic remote exec functionality"""
        script = 'print("Remote script executed successfully!")'
        returncode, stdout, stderr = self._run_remote_exec_test(script)
        # self.assertEqual(returncode, 0)
        self.assertIn(b"Remote script executed successfully!", stdout)
        self.assertEqual(stderr, b"")

    def test_remote_exec_bytes(self):
        script = 'print("Remote script executed successfully!")'
        script_path = os.fsencode(os_helper.TESTFN) + b'_bytes_remote.py'
        returncode, stdout, stderr = self._run_remote_exec_test(script,
                                                    script_path=script_path)
        self.assertIn(b"Remote script executed successfully!", stdout)
        self.assertEqual(stderr, b"")

    @unittest.skipUnless(os_helper.TESTFN_UNDECODABLE, 'requires undecodable path')
    @unittest.skipIf(sys.platform == 'darwin',
                     'undecodable paths are not supported on macOS')
    def test_remote_exec_undecodable(self):
        script = 'print("Remote script executed successfully!")'
        script_path = os_helper.TESTFN_UNDECODABLE + b'_undecodable_remote.py'
        for script_path in [script_path, os.fsdecode(script_path)]:
            returncode, stdout, stderr = self._run_remote_exec_test(script,
                                                        script_path=script_path)
            self.assertIn(b"Remote script executed successfully!", stdout)
            self.assertEqual(stderr, b"")

    def test_remote_exec_with_self_process(self):
        """Test remote exec with the target process being the same as the test process"""

        code = 'import sys;print("Remote script executed successfully!", file=sys.stderr)'
        file = os_helper.TESTFN + '_remote_self.py'
        with open(file, 'w') as f:
            f.write(code)
        self.addCleanup(os_helper.unlink, file)
        with mock.patch('sys.stderr', new_callable=StringIO) as mock_stderr:
            with mock.patch('sys.stdout', new_callable=StringIO) as mock_stdout:
                sys.remote_exec(os.getpid(), os.path.abspath(file))
                print("Done")
                self.assertEqual(mock_stderr.getvalue(), "Remote script executed successfully!\n")
                self.assertEqual(mock_stdout.getvalue(), "Done\n")

    def test_remote_exec_raises_audit_event(self):
        """Test remote exec raises an audit event"""
        prologue = '''\
import sys
def audit_hook(event, arg):
    print(f"Audit event: {event}, arg: {arg}".encode("ascii", errors="replace"))
sys.addaudithook(audit_hook)
'''
        script = '''
print("Remote script executed successfully!")
'''
        returncode, stdout, stderr = self._run_remote_exec_test(script, prologue=prologue)
        self.assertEqual(returncode, 0)
        self.assertIn(b"Remote script executed successfully!", stdout)
        self.assertIn(b"Audit event: cpython.remote_debugger_script, arg: ", stdout)
        self.assertEqual(stderr, b"")

    def test_remote_exec_with_exception(self):
        """Test remote exec with an exception raised in the target process

        The exception should be raised in the main thread of the target process
        but not crash the target process.
        """
        script = '''
raise Exception("Remote script exception")
'''
        returncode, stdout, stderr = self._run_remote_exec_test(script)
        self.assertEqual(returncode, 0)
        self.assertIn(b"Remote script exception", stderr)
        self.assertEqual(stdout.strip(), b"Target process running...")

    def test_new_namespace_for_each_remote_exec(self):
        """Test that each remote_exec call gets its own namespace."""
        script = textwrap.dedent(
            """
            assert globals() is not __import__("__main__").__dict__
            print("Remote script executed successfully!")
            """
        )
        returncode, stdout, stderr = self._run_remote_exec_test(script)
        self.assertEqual(returncode, 0)
        self.assertEqual(stderr, b"")
        self.assertIn(b"Remote script executed successfully", stdout)

    def test_remote_exec_disabled_by_env(self):
        """Test remote exec is disabled when PYTHON_DISABLE_REMOTE_DEBUG is set"""
        env = os.environ.copy()
        env['PYTHON_DISABLE_REMOTE_DEBUG'] = '1'
        with self.assertRaisesRegex(RuntimeError, "Remote debugging is not enabled in the remote process"):
            self._run_remote_exec_test("print('should not run')", env=env)

    def test_remote_exec_disabled_by_xoption(self):
        """Test remote exec is disabled with -Xdisable-remote-debug"""
        with self.assertRaisesRegex(RuntimeError, "Remote debugging is not enabled in the remote process"):
            self._run_remote_exec_test("print('should not run')", python_args=['-Xdisable-remote-debug'])

    def test_remote_exec_invalid_pid(self):
        """Test remote exec with invalid process ID"""
        with self.assertRaises(OSError):
            sys.remote_exec(99999, "print('should not run')")

    def test_remote_exec_invalid_script(self):
        """Test remote exec with invalid script type"""
        with self.assertRaises(TypeError):
            sys.remote_exec(0, None)
        with self.assertRaises(TypeError):
            sys.remote_exec(0, 123)

    def test_remote_exec_syntax_error(self):
        """Test remote exec with syntax error in script"""
        script = '''
this is invalid python code
'''
        returncode, stdout, stderr = self._run_remote_exec_test(script)
        self.assertEqual(returncode, 0)
        self.assertIn(b"SyntaxError", stderr)
        self.assertEqual(stdout.strip(), b"Target process running...")

    def test_remote_exec_invalid_script_path(self):
        """Test remote exec with invalid script path"""
        with self.assertRaises(OSError):
            sys.remote_exec(os.getpid(), "invalid_script_path")

    @unittest.skipUnless(sys.platform == 'linux', 'Linux-only regression test')
    @unittest.skipUnless(
        sysconfig.get_config_var('Py_ENABLE_SHARED') == 1,
        'requires a shared libpython build')
    def test_remote_exec_deleted_libpython(self):
        """Test remote exec when the target libpython was deleted."""
        build_dir = sysconfig.get_config_var('abs_builddir')
        ldlibrary = sysconfig.get_config_var('LDLIBRARY')
        instsoname = sysconfig.get_config_var('INSTSONAME')
        if not build_dir or not ldlibrary or not instsoname:
            self.skipTest('cannot determine shared libpython location')

        source_libpython = os.path.join(build_dir, instsoname)
        if not os.path.exists(source_libpython):
            self.skipTest(f'{source_libpython!r} does not exist')

        with os_helper.temp_dir() as lib_dir:
            copied_libpython = os.path.join(lib_dir, instsoname)
            shutil.copy2(source_libpython, copied_libpython)
            if ldlibrary != instsoname:
                os.symlink(instsoname, os.path.join(lib_dir, ldlibrary))

            env = os.environ.copy()
            ld_library_path = env.get('LD_LIBRARY_PATH')
            env['LD_LIBRARY_PATH'] = lib_dir if not ld_library_path else (
                lib_dir + os.pathsep + ld_library_path)

            self._run_remote_exec_with_deleted_mapping(copied_libpython,
                                                       env=env)

    @unittest.skipUnless(sys.platform == 'linux', 'Linux-only regression test')
    @unittest.skipUnless(
        sysconfig.get_config_var('Py_ENABLE_SHARED') == 0,
        'requires a static Python build')
    def test_remote_exec_deleted_static_executable(self):
        """Test remote exec when the target static executable was deleted."""
        build_dir = sysconfig.get_config_var('abs_builddir')
        stdlib_dir = os.path.dirname(os.path.abspath(os.__file__))
        if not build_dir or not os.path.isdir(stdlib_dir):
            self.skipTest('cannot determine build-tree locations')

        pybuilddir_txt = os.path.join(build_dir, 'pybuilddir.txt')
        if not os.path.exists(pybuilddir_txt):
            self.skipTest(f'{pybuilddir_txt!r} does not exist')

        with open(pybuilddir_txt, encoding='utf-8') as pybuilddir_file:
            pybuilddir = pybuilddir_file.read().strip()
        source_ext_dir = os.path.join(build_dir, pybuilddir)
        if not os.path.isdir(source_ext_dir):
            self.skipTest(f'{source_ext_dir!r} does not exist')

        with os_helper.temp_dir() as copied_root:
            copied_build_dir = os.path.join(copied_root, 'build')
            copied_pybuilddir = os.path.join(copied_build_dir, pybuilddir)
            os.makedirs(os.path.dirname(copied_pybuilddir))
            os.symlink(stdlib_dir, os.path.join(copied_root, 'Lib'))
            os.symlink(source_ext_dir, copied_pybuilddir)
            shutil.copy2(pybuilddir_txt,
                         os.path.join(copied_build_dir, 'pybuilddir.txt'))

            copied_python = os.path.join(copied_build_dir,
                                         os.path.basename(sys.executable))
            shutil.copy2(sys.executable, copied_python)

            self._run_remote_exec_with_deleted_mapping(
                copied_python, python_args=['-S'],
                python_executable=copied_python)

    def test_remote_exec_in_process_without_debug_fails_envvar(self):
        """Test remote exec in a process without remote debugging enabled"""
        script = os_helper.TESTFN + '_remote.py'
        self.addCleanup(os_helper.unlink, script)
        with open(script, 'w') as f:
            f.write('print("Remote script executed successfully!")')
        env = os.environ.copy()
        env['PYTHON_DISABLE_REMOTE_DEBUG'] = '1'

        _, out, err = assert_python_failure('-c', f'import os, sys; sys.remote_exec(os.getpid(), "{script}")', **env)
        self.assertIn(b"Remote debugging is not enabled", err)
        self.assertEqual(out, b"")

    def test_remote_exec_in_process_without_debug_fails_xoption(self):
        """Test remote exec in a process without remote debugging enabled"""
        script = os_helper.TESTFN + '_remote.py'
        self.addCleanup(os_helper.unlink, script)
        with open(script, 'w') as f:
            f.write('print("Remote script executed successfully!")')

        _, out, err = assert_python_failure('-Xdisable-remote-debug', '-c', f'import os, sys; sys.remote_exec(os.getpid(), "{script}")')
        self.assertIn(b"Remote debugging is not enabled", err)
        self.assertEqual(out, b"")

class TestSysJIT(unittest.TestCase):

    def test_jit_is_available(self):
        available = sys._jit.is_available()
        script = f"import sys; assert sys._jit.is_available() is {available}"
        assert_python_ok("-c", script, PYTHON_JIT="0")
        assert_python_ok("-c", script, PYTHON_JIT="1")

    def test_jit_is_enabled(self):
        available = sys._jit.is_available()
        script = "import sys; assert sys._jit.is_enabled() is {enabled}"
        assert_python_ok("-c", script.format(enabled=False), PYTHON_JIT="0")
        assert_python_ok("-c", script.format(enabled=available), PYTHON_JIT="1")

    def test_jit_is_active(self):
        available = sys._jit.is_available()
        script = textwrap.dedent(
            """
            import _testcapi
            import _testinternalcapi
            import sys

            def frame_0_interpreter() -> None:
                assert sys._jit.is_active() is False

            def frame_1_interpreter() -> None:
                assert sys._jit.is_active() is False
                frame_0_interpreter()
                assert sys._jit.is_active() is False

            def frame_2_jit(expected: bool) -> None:
                # Inlined into the last loop of frame_3_jit:
                assert sys._jit.is_active() is expected
                # Insert C frame:
                _testcapi.pyobject_vectorcall(frame_1_interpreter, None, None)
                assert sys._jit.is_active() is expected

            def frame_3_jit() -> None:
                # JITs just before the last loop:
                # 1 extra iteration for tracing.
                for i in range(_testinternalcapi.TIER2_THRESHOLD + 2):
                    # Careful, doing this in the reverse order breaks tracing:
                    expected = {enabled} and i >= _testinternalcapi.TIER2_THRESHOLD
                    assert sys._jit.is_active() is expected
                    frame_2_jit(expected)
                    assert sys._jit.is_active() is expected

            def frame_4_interpreter() -> None:
                assert sys._jit.is_active() is False
                frame_3_jit()
                assert sys._jit.is_active() is False

            assert sys._jit.is_active() is False
            frame_4_interpreter()
            assert sys._jit.is_active() is False
            """
        )
        assert_python_ok("-c", script.format(enabled=False), PYTHON_JIT="0")
        assert_python_ok("-c", script.format(enabled=available), PYTHON_JIT="1")


if __name__ == "__main__":
    unittest.main()