from contextlib import contextmanager
import linecache
import logging
import os
import importlib
import inspect
from io import StringIO
import re
import sys
import textwrap
import types
from typing import overload, get_overloads
import unittest
from test import support
from test.support import import_helper
from test.support import os_helper
from test.support import warnings_helper
from test.support import force_not_colorized
from test.support.script_helper import assert_python_ok, assert_python_failure

from test.test_warnings.data import package_helper
from test.test_warnings.data import stacklevel as warning_tests

import warnings as original_warnings
from warnings import deprecated


py_warnings = import_helper.import_fresh_module('_py_warnings')
py_warnings._set_module(py_warnings)

c_warnings = import_helper.import_fresh_module(
    "warnings", fresh=["_warnings", "_py_warnings"]
)
c_warnings._set_module(c_warnings)

@contextmanager
def warnings_state(module):
    """Use a specific warnings implementation in warning_tests."""
    global __warningregistry__
    for to_clear in (sys, warning_tests):
        try:
            to_clear.__warningregistry__.clear()
        except AttributeError:
            pass
    try:
        __warningregistry__.clear()
    except NameError:
        pass
    original_warnings = warning_tests.warnings
    if module._use_context:
        saved_context, context = module._new_context()
    else:
        original_filters = module.filters
        module.filters = original_filters[:]
    try:
        module.simplefilter("once")
        warning_tests.warnings = module
        yield
    finally:
        warning_tests.warnings = original_warnings
        if module._use_context:
            module._set_context(saved_context)
        else:
            module.filters = original_filters


class TestWarning(Warning):
    pass


class BaseTest:

    """Basic bookkeeping required for testing."""

    def setUp(self):
        self.old_unittest_module = unittest.case.warnings
        # The __warningregistry__ needs to be in a pristine state for tests
        # to work properly.
        if '__warningregistry__' in globals():
            del globals()['__warningregistry__']
        if hasattr(warning_tests, '__warningregistry__'):
            del warning_tests.__warningregistry__
        if hasattr(sys, '__warningregistry__'):
            del sys.__warningregistry__
        # The 'warnings' module must be explicitly set so that the proper
        # interaction between _warnings and 'warnings' can be controlled.
        sys.modules['warnings'] = self.module
        # Ensure that unittest.TestCase.assertWarns() uses the same warnings
        # module than warnings.catch_warnings(). Otherwise,
        # warnings.catch_warnings() will be unable to remove the added filter.
        unittest.case.warnings = self.module
        super(BaseTest, self).setUp()

    def tearDown(self):
        sys.modules['warnings'] = original_warnings
        unittest.case.warnings = self.old_unittest_module
        super(BaseTest, self).tearDown()

class PublicAPITests(BaseTest):

    """Ensures that the correct values are exposed in the
    public API.
    """

    def test_module_all_attribute(self):
        self.assertHasAttr(self.module, '__all__')
        target_api = ["warn", "warn_explicit", "showwarning",
                      "formatwarning", "filterwarnings", "simplefilter",
                      "resetwarnings", "catch_warnings", "deprecated"]
        self.assertSetEqual(set(self.module.__all__),
                            set(target_api))

class CPublicAPITests(PublicAPITests, unittest.TestCase):
    module = c_warnings

class PyPublicAPITests(PublicAPITests, unittest.TestCase):
    module = py_warnings

class FilterTests(BaseTest):

    """Testing the filtering functionality."""

    def test_error(self):
        with self.module.catch_warnings() as w:
            self.module.resetwarnings()
            self.module.filterwarnings("error", category=UserWarning)
            self.assertRaises(UserWarning, self.module.warn,
                                "FilterTests.test_error")

    def test_error_after_default(self):
        with self.module.catch_warnings() as w:
            self.module.resetwarnings()
            message = "FilterTests.test_ignore_after_default"
            def f():
                self.module.warn(message, UserWarning)

            with support.captured_stderr() as stderr:
                f()
            stderr = stderr.getvalue()
            self.assertIn("UserWarning: FilterTests.test_ignore_after_default",
                          stderr)
            self.assertIn("self.module.warn(message, UserWarning)",
                          stderr)

            self.module.filterwarnings("error", category=UserWarning)
            self.assertRaises(UserWarning, f)

    def test_ignore(self):
        with self.module.catch_warnings(record=True) as w:
            self.module.resetwarnings()
            self.module.filterwarnings("ignore", category=UserWarning)
            self.module.warn("FilterTests.test_ignore", UserWarning)
            self.assertEqual(len(w), 0)
            self.assertEqual(list(__warningregistry__), ['version'])

    def test_ignore_after_default(self):
        with self.module.catch_warnings(record=True) as w:
            self.module.resetwarnings()
            message = "FilterTests.test_ignore_after_default"
            def f():
                self.module.warn(message, UserWarning)
            f()
            self.module.filterwarnings("ignore", category=UserWarning)
            f()
            f()
            self.assertEqual(len(w), 1)

    def test_always_and_all(self):
        for mode in {"always", "all"}:
            with self.module.catch_warnings(record=True) as w:
                self.module.resetwarnings()
                self.module.filterwarnings(mode, category=UserWarning)
                message = "FilterTests.test_always_and_all"
                def f():
                    self.module.warn(message, UserWarning)
                f()
                self.assertEqual(len(w), 1)
                self.assertEqual(w[-1].message.args[0], message)
                f()
                self.assertEqual(len(w), 2)
                self.assertEqual(w[-1].message.args[0], message)

    def test_always_and_all_after_default(self):
        for mode in {"always", "all"}:
            with self.module.catch_warnings(record=True) as w:
                self.module.resetwarnings()
                message = "FilterTests.test_always_and_all_after_ignore"
                def f():
                    self.module.warn(message, UserWarning)
                f()
                self.assertEqual(len(w), 1)
                self.assertEqual(w[-1].message.args[0], message)
                f()
                self.assertEqual(len(w), 1)
                self.module.filterwarnings(mode, category=UserWarning)
                f()
                self.assertEqual(len(w), 2)
                self.assertEqual(w[-1].message.args[0], message)
                f()
                self.assertEqual(len(w), 3)
                self.assertEqual(w[-1].message.args[0], message)

    def test_default(self):
        with self.module.catch_warnings(record=True) as w:
            self.module.resetwarnings()
            self.module.filterwarnings("default", category=UserWarning)
            message = UserWarning("FilterTests.test_default")
            for x in range(2):
                self.module.warn(message, UserWarning)
                if x == 0:
                    self.assertEqual(w[-1].message, message)
                    del w[:]
                elif x == 1:
                    self.assertEqual(len(w), 0)
                else:
                    raise ValueError("loop variant unhandled")

    def test_module(self):
        with self.module.catch_warnings(record=True) as w:
            self.module.resetwarnings()
            self.module.filterwarnings("module", category=UserWarning)
            message = UserWarning("FilterTests.test_module")
            self.module.warn(message, UserWarning)
            self.assertEqual(w[-1].message, message)
            del w[:]
            self.module.warn(message, UserWarning)
            self.assertEqual(len(w), 0)

    def test_once(self):
        with self.module.catch_warnings(record=True) as w:
            self.module.resetwarnings()
            self.module.filterwarnings("once", category=UserWarning)
            message = UserWarning("FilterTests.test_once")
            self.module.warn_explicit(message, UserWarning, "__init__.py",
                                    42)
            self.assertEqual(w[-1].message, message)
            del w[:]
            self.module.warn_explicit(message, UserWarning, "__init__.py",
                                    13)
            self.assertEqual(len(w), 0)
            self.module.warn_explicit(message, UserWarning, "test_warnings2.py",
                                    42)
            self.assertEqual(len(w), 0)

    def test_filter_module(self):
        MS_WINDOWS = (sys.platform == 'win32')
        with self.module.catch_warnings(record=True) as w:
            self.module.simplefilter('error')
            self.module.filterwarnings('always', module=r'package\.module\z')
            self.module.warn_explicit('msg', UserWarning, 'filename', 42,
                                      module='package.module')
            self.assertEqual(len(w), 1)
            with self.assertRaises(UserWarning):
                self.module.warn_explicit('msg', UserWarning, '/path/to/package/module', 42)
            with self.assertRaises(UserWarning):
                self.module.warn_explicit('msg', UserWarning, '/path/to/package/module.py', 42)

        with self.module.catch_warnings(record=True) as w:
            self.module.simplefilter('error')
            self.module.filterwarnings('always', module='package')
            self.module.warn_explicit('msg', UserWarning, 'filename', 42,
                                      module='package.module')
            self.assertEqual(len(w), 1)
            with self.assertRaises(UserWarning):
                self.module.warn_explicit('msg', UserWarning, 'filename', 42,
                                          module='other.package.module')
            with self.assertRaises(UserWarning):
                self.module.warn_explicit('msg', UserWarning, '/path/to/otherpackage/module.py', 42)

        with self.module.catch_warnings(record=True) as w:
            self.module.simplefilter('error')
            self.module.filterwarnings('always', module=r'/path/to/package/module\z')
            self.module.warn_explicit('msg', UserWarning, '/path/to/package/module', 42)
            self.assertEqual(len(w), 1)
            self.module.warn_explicit('msg', UserWarning, '/path/to/package/module.py', 42)
            self.assertEqual(len(w), 2)
            with self.assertRaises(UserWarning):
                self.module.warn_explicit('msg', UserWarning, '/PATH/TO/PACKAGE/MODULE', 42)
            if MS_WINDOWS:
                if self.module is py_warnings:
                    self.module.warn_explicit('msg', UserWarning, r'/path/to/package/module.PY', 42)
                    self.assertEqual(len(w), 3)
                with self.assertRaises(UserWarning):
                    self.module.warn_explicit('msg', UserWarning, r'/path/to/package/module/__init__.py', 42)
                with self.assertRaises(UserWarning):
                    self.module.warn_explicit('msg', UserWarning, r'/path/to/package/module.pyw', 42)
                with self.assertRaises(UserWarning):
                    self.module.warn_explicit('msg', UserWarning, r'\path\to\package\module', 42)

        with self.module.catch_warnings(record=True) as w:
            self.module.simplefilter('error')
            self.module.filterwarnings('always', module=r'/path/to/package/__init__\z')
            self.module.warn_explicit('msg', UserWarning, '/path/to/package/__init__.py', 42)
            self.assertEqual(len(w), 1)
            self.module.warn_explicit('msg', UserWarning, '/path/to/package/__init__', 42)
            self.assertEqual(len(w), 2)

        if MS_WINDOWS:
            with self.module.catch_warnings(record=True) as w:
                self.module.simplefilter('error')
                self.module.filterwarnings('always', module=r'C:\\path\\to\\package\\module\z')
                self.module.warn_explicit('msg', UserWarning, r'C:\path\to\package\module', 42)
                self.assertEqual(len(w), 1)
                self.module.warn_explicit('msg', UserWarning, r'C:\path\to\package\module.py', 42)
                self.assertEqual(len(w), 2)
                if self.module is py_warnings:
                    self.module.warn_explicit('msg', UserWarning, r'C:\path\to\package\module.PY', 42)
                    self.assertEqual(len(w), 3)
                with self.assertRaises(UserWarning):
                    self.module.warn_explicit('msg', UserWarning, r'C:\path\to\package\module.pyw', 42)
                with self.assertRaises(UserWarning):
                    self.module.warn_explicit('msg', UserWarning, r'C:\PATH\TO\PACKAGE\MODULE', 42)
                with self.assertRaises(UserWarning):
                    self.module.warn_explicit('msg', UserWarning, r'C:/path/to/package/module', 42)
                with self.assertRaises(UserWarning):
                    self.module.warn_explicit('msg', UserWarning, r'C:\path\to\package\module\__init__.py', 42)

        with self.module.catch_warnings(record=True) as w:
            self.module.simplefilter('error')
            self.module.filterwarnings('always', module=r'<unknown>\z')
            self.module.warn_explicit('msg', UserWarning, '', 42)
            self.assertEqual(len(w), 1)

    def test_module_globals(self):
        with self.module.catch_warnings(record=True) as w:
            self.module.simplefilter("always", UserWarning)

            # bpo-33509: module_globals=None must not crash
            self.module.warn_explicit('msg', UserWarning, "filename", 42,
                                      module_globals=None)
            self.assertEqual(len(w), 1)

            # Invalid module_globals type
            with self.assertRaises(TypeError):
                self.module.warn_explicit('msg', UserWarning, "filename", 42,
                                          module_globals=True)
            self.assertEqual(len(w), 1)

            # Empty module_globals
            self.module.warn_explicit('msg', UserWarning, "filename", 42,
                                      module_globals={})
            self.assertEqual(len(w), 2)

    def test_inheritance(self):
        with self.module.catch_warnings() as w:
            self.module.resetwarnings()
            self.module.filterwarnings("error", category=Warning)
            self.assertRaises(UserWarning, self.module.warn,
                                "FilterTests.test_inheritance", UserWarning)

    def test_ordering(self):
        with self.module.catch_warnings(record=True) as w:
            self.module.resetwarnings()
            self.module.filterwarnings("ignore", category=UserWarning)
            self.module.filterwarnings("error", category=UserWarning,
                                        append=True)
            del w[:]
            try:
                self.module.warn("FilterTests.test_ordering", UserWarning)
            except UserWarning:
                self.fail("order handling for actions failed")
            self.assertEqual(len(w), 0)

    def test_filterwarnings(self):
        # Test filterwarnings().
        # Implicitly also tests resetwarnings().
        with self.module.catch_warnings(record=True) as w:
            self.module.filterwarnings("error", "", Warning, "", 0)
            self.assertRaises(UserWarning, self.module.warn, 'convert to error')

            self.module.resetwarnings()
            text = 'handle normally'
            self.module.warn(text)
            self.assertEqual(str(w[-1].message), text)
            self.assertIs(w[-1].category, UserWarning)

            self.module.filterwarnings("ignore", "", Warning, "", 0)
            text = 'filtered out'
            self.module.warn(text)
            self.assertNotEqual(str(w[-1].message), text)

            self.module.resetwarnings()
            self.module.filterwarnings("error", "hex*", Warning, "", 0)
            self.assertRaises(UserWarning, self.module.warn, 'hex/oct')
            text = 'nonmatching text'
            self.module.warn(text)
            self.assertEqual(str(w[-1].message), text)
            self.assertIs(w[-1].category, UserWarning)

    def test_message_matching(self):
        with self.module.catch_warnings(record=True) as w:
            self.module.simplefilter("ignore", UserWarning)
            self.module.filterwarnings("error", "match", UserWarning)
            self.assertRaises(UserWarning, self.module.warn, "match")
            self.assertRaises(UserWarning, self.module.warn, "match prefix")
            self.module.warn("suffix match")
            self.assertEqual(w, [])
            self.module.warn("something completely different")
            self.assertEqual(w, [])

    def test_mutate_filter_list(self):
        class X:
            def match(self, a):
                L[:] = []

        L = [("default",X(),UserWarning,X(),0) for i in range(2)]
        with self.module.catch_warnings(record=True) as w:
            self.module.filters = L
            self.module.warn_explicit(UserWarning("b"), None, "f.py", 42)
            self.assertEqual(str(w[-1].message), "b")

    def test_filterwarnings_duplicate_filters(self):
        with self.module.catch_warnings():
            self.module.resetwarnings()
            self.module.filterwarnings("error", category=UserWarning)
            self.assertEqual(len(self.module._get_filters()), 1)
            self.module.filterwarnings("ignore", category=UserWarning)
            self.module.filterwarnings("error", category=UserWarning)
            self.assertEqual(
                len(self.module._get_filters()), 2,
                "filterwarnings inserted duplicate filter"
            )
            self.assertEqual(
                self.module._get_filters()[0][0], "error",
                "filterwarnings did not promote filter to "
                "the beginning of list"
            )

    def test_simplefilter_duplicate_filters(self):
        with self.module.catch_warnings():
            self.module.resetwarnings()
            self.module.simplefilter("error", category=UserWarning)
            self.assertEqual(len(self.module._get_filters()), 1)
            self.module.simplefilter("ignore", category=UserWarning)
            self.module.simplefilter("error", category=UserWarning)
            self.assertEqual(
                len(self.module._get_filters()), 2,
                "simplefilter inserted duplicate filter"
            )
            self.assertEqual(
                self.module._get_filters()[0][0], "error",
                "simplefilter did not promote filter to the beginning of list"
            )

    def test_append_duplicate(self):
        with self.module.catch_warnings(record=True) as w:
            self.module.resetwarnings()
            self.module.simplefilter("ignore")
            self.module.simplefilter("error", append=True)
            self.module.simplefilter("ignore", append=True)
            self.module.warn("test_append_duplicate", category=UserWarning)
            self.assertEqual(len(self.module._get_filters()), 2,
                "simplefilter inserted duplicate filter"
            )
            self.assertEqual(len(w), 0,
                "appended duplicate changed order of filters"
            )

    def test_argument_validation(self):
        with self.assertRaises(ValueError):
            self.module.filterwarnings(action='foo')
        with self.assertRaises(TypeError):
            self.module.filterwarnings('ignore', message=0)
        with self.assertRaises(TypeError):
            self.module.filterwarnings('ignore', category=0)
        with self.assertRaises(TypeError):
            self.module.filterwarnings('ignore', category=int)
        with self.assertRaises(TypeError):
            self.module.filterwarnings('ignore', module=0)
        with self.assertRaises(TypeError):
            self.module.filterwarnings('ignore', lineno=int)
        with self.assertRaises(ValueError):
            self.module.filterwarnings('ignore', lineno=-1)
        with self.assertRaises(ValueError):
            self.module.simplefilter(action='foo')
        with self.assertRaises(TypeError):
            self.module.simplefilter('ignore', lineno=int)
        with self.assertRaises(ValueError):
            self.module.simplefilter('ignore', lineno=-1)

    def test_catchwarnings_with_simplefilter_ignore(self):
        with self.module.catch_warnings(module=self.module):
            self.module.resetwarnings()
            self.module.simplefilter("error")
            with self.module.catch_warnings(action="ignore"):
                self.module.warn("This will be ignored")

    def test_catchwarnings_with_simplefilter_error(self):
        with self.module.catch_warnings():
            self.module.resetwarnings()
            with self.module.catch_warnings(
                action="error", category=FutureWarning
            ):
                with support.captured_stderr() as stderr:
                    error_msg = "Other types of warnings are not errors"
                    self.module.warn(error_msg)
                    self.assertRaises(FutureWarning,
                                      self.module.warn, FutureWarning("msg"))
                    stderr = stderr.getvalue()
                    self.assertIn(error_msg, stderr)

    def test_catchwarnings_with_showwarning(self):
        # gh-146358: catch_warnings must override warnings.showwarning()
        # if it's not the default implementation.

        warns = []
        def custom_showwarning(message, category, filename, lineno,
                               file=None, line=None):
            warns.append(message)

        with self.module.catch_warnings():
            self.module.resetwarnings()

            with support.swap_attr(self.module, 'showwarning',
                                   custom_showwarning):
                with self.module.catch_warnings(record=True) as recorded:
                    self.module.warn("recorded")
                self.assertEqual(len(recorded), 1)
                self.assertEqual(str(recorded[0].message), 'recorded')
                self.assertIs(self.module.showwarning, custom_showwarning)

                self.module.warn("custom")

        self.assertEqual(len(warns), 1)
        self.assertEqual(str(warns[0]), "custom")

    def test_catchwarnings_logging(self):
        # gh-146358: catch_warnings(record=True) must replace the
        # showwarning() function set by logging.captureWarnings(True).

        with self.module.catch_warnings():
            self.module.resetwarnings()
            logging.captureWarnings(True)

            with self.module.catch_warnings(record=True) as recorded:
                self.module.warn("recorded")
            self.assertEqual(len(recorded), 1)
            self.assertEqual(str(recorded[0].message), 'recorded')

            logging.captureWarnings(False)


class CFilterTests(FilterTests, unittest.TestCase):
    module = c_warnings

class PyFilterTests(FilterTests, unittest.TestCase):
    module = py_warnings


class WarnTests(BaseTest):

    """Test warnings.warn() and warnings.warn_explicit()."""

    def test_message(self):
        with self.module.catch_warnings(record=True) as w:
            self.module.simplefilter("once")
            for i in range(4):
                text = 'multi %d' %i  # Different text on each call.
                self.module.warn(text)
                self.assertEqual(str(w[-1].message), text)
                self.assertIs(w[-1].category, UserWarning)

    # Issue 3639
    def test_warn_nonstandard_types(self):
        # warn() should handle non-standard types without issue.
        for ob in (Warning, None, 42):
            with self.module.catch_warnings(record=True) as w:
                self.module.simplefilter("once")
                self.module.warn(ob)
                # Don't directly compare objects since
                # ``Warning() != Warning()``.
                self.assertEqual(str(w[-1].message), str(UserWarning(ob)))

    def test_filename(self):
        with warnings_state(self.module):
            with self.module.catch_warnings(record=True) as w:
                warning_tests.inner("spam1")
                self.assertEqual(os.path.basename(w[-1].filename),
                                    "stacklevel.py")
                warning_tests.outer("spam2")
                self.assertEqual(os.path.basename(w[-1].filename),
                                    "stacklevel.py")

    def test_stacklevel(self):
        # Test stacklevel argument
        # make sure all messages are different, so the warning won't be skipped
        with warnings_state(self.module):
            with self.module.catch_warnings(record=True) as w:
                warning_tests.inner("spam3", stacklevel=1)
                self.assertEqual(os.path.basename(w[-1].filename),
                                    "stacklevel.py")
                warning_tests.outer("spam4", stacklevel=1)
                self.assertEqual(os.path.basename(w[-1].filename),
                                    "stacklevel.py")

                warning_tests.inner("spam5", stacklevel=2)
                self.assertEqual(os.path.basename(w[-1].filename),
                                    "__init__.py")
                warning_tests.outer("spam6", stacklevel=2)
                self.assertEqual(os.path.basename(w[-1].filename),
                                    "stacklevel.py")
                warning_tests.outer("spam6.5", stacklevel=3)
                self.assertEqual(os.path.basename(w[-1].filename),
                                    "__init__.py")

                warning_tests.inner("spam7", stacklevel=9999)
                self.assertEqual(os.path.basename(w[-1].filename),
                                    "<sys>")

    def test_stacklevel_import(self):
        # Issue #24305: With stacklevel=2, module-level warnings should work.
        import_helper.unload('test.test_warnings.data.import_warning')
        with warnings_state(self.module):
            with self.module.catch_warnings(record=True) as w:
                self.module.simplefilter('always')
                import test.test_warnings.data.import_warning  # noqa: F401
                self.assertEqual(len(w), 1)
                self.assertEqual(w[0].filename, __file__)

    def test_skip_file_prefixes(self):
        with warnings_state(self.module):
            with self.module.catch_warnings(record=True) as w:
                self.module.simplefilter('always')

                # Warning never attributed to the data/ package.
                package_helper.inner_api(
                        "inner_api", stacklevel=2,
                        warnings_module=warning_tests.warnings)
                self.assertEqual(w[-1].filename, __file__)
                warning_tests.package("package api", stacklevel=2)
                self.assertEqual(w[-1].filename, __file__)
                self.assertEqual(w[-2].filename, w[-1].filename)
                # Low stacklevels are overridden to 2 behavior.
                warning_tests.package("package api 1", stacklevel=1)
                self.assertEqual(w[-1].filename, __file__)
                warning_tests.package("package api 0", stacklevel=0)
                self.assertEqual(w[-1].filename, __file__)
                warning_tests.package("package api -99", stacklevel=-99)
                self.assertEqual(w[-1].filename, __file__)

                # The stacklevel still goes up out of the package.
                warning_tests.package("prefix02", stacklevel=3)
                self.assertIn("unittest", w[-1].filename)

    def test_skip_file_prefixes_file_path(self):
        # see: gh-126209
        with warnings_state(self.module):
            skipped = warning_tests.__file__
            with self.module.catch_warnings(record=True) as w:
                warning_tests.outer("msg", skip_file_prefixes=(skipped,))

            self.assertEqual(len(w), 1)
            self.assertNotEqual(w[-1].filename, skipped)

    def test_skip_file_prefixes_type_errors(self):
        with warnings_state(self.module):
            warn = warning_tests.warnings.warn
            with self.assertRaises(TypeError):
                warn("msg", skip_file_prefixes=[])
            with self.assertRaises(TypeError):
                warn("msg", skip_file_prefixes=(b"bytes",))
            with self.assertRaises(TypeError):
                warn("msg", skip_file_prefixes="a sequence of strs")

    def test_exec_filename(self):
        filename = "<warnings-test>"
        codeobj = compile(("import warnings\n"
                           "warnings.warn('hello', UserWarning)"),
                          filename, "exec")
        with self.module.catch_warnings(record=True) as w:
            self.module.simplefilter("always", category=UserWarning)
            exec(codeobj)
        self.assertEqual(w[0].filename, filename)

    def test_warn_explicit_non_ascii_filename(self):
        with self.module.catch_warnings(record=True) as w:
            self.module.resetwarnings()
            self.module.filterwarnings("always", category=UserWarning)
            filenames = ["nonascii\xe9\u20ac", "surrogate\udc80"]
            for filename in filenames:
                try:
                    os.fsencode(filename)
                except UnicodeEncodeError:
                    continue
                self.module.warn_explicit("text", UserWarning, filename, 1)
                self.assertEqual(w[-1].filename, filename)

    def test_warn_explicit_type_errors(self):
        # warn_explicit() should error out gracefully if it is given objects
        # of the wrong types.
        # lineno is expected to be an integer.
        self.assertRaises(TypeError, self.module.warn_explicit,
                            None, UserWarning, None, None)
        # Either 'message' needs to be an instance of Warning or 'category'
        # needs to be a subclass.
        self.assertRaises(TypeError, self.module.warn_explicit,
                            None, None, None, 1)
        # 'registry' must be a dict or None.
        self.assertRaises((TypeError, AttributeError),
                            self.module.warn_explicit,
                            None, Warning, None, 1, registry=42)

    def test_bad_str(self):
        # issue 6415
        # Warnings instance with a bad format string for __str__ should not
        # trigger a bus error.
        class BadStrWarning(Warning):
            """Warning with a bad format string for __str__."""
            def __str__(self):
                return ("A bad formatted string %(err)" %
                        {"err" : "there is no %(err)s"})

        with self.assertRaises(ValueError):
            self.module.warn(BadStrWarning())

    def test_warning_classes(self):
        class MyWarningClass(Warning):
            pass

        class NonWarningSubclass:
            pass

        # passing a non-subclass of Warning should raise a TypeError
        with self.assertRaises(TypeError) as cm:
            self.module.warn('bad warning category', '')
        self.assertIn('category must be a Warning subclass, not ',
                      str(cm.exception))

        with self.assertRaises(TypeError) as cm:
            self.module.warn('bad warning category', NonWarningSubclass)
        self.assertIn('category must be a Warning subclass, not ',
                      str(cm.exception))

        # check that warning instances also raise a TypeError
        with self.assertRaises(TypeError) as cm:
            self.module.warn('bad warning category', MyWarningClass())
        self.assertIn('category must be a Warning subclass, not ',
                      str(cm.exception))

        with self.module.catch_warnings():
            self.module.resetwarnings()
            self.module.filterwarnings('default')
            with self.assertWarns(MyWarningClass) as cm:
                self.module.warn('good warning category', MyWarningClass)
            self.assertEqual('good warning category', str(cm.warning))

            with self.assertWarns(UserWarning) as cm:
                self.module.warn('good warning category', None)
            self.assertEqual('good warning category', str(cm.warning))

            with self.assertWarns(MyWarningClass) as cm:
                self.module.warn('good warning category', MyWarningClass)
            self.assertIsInstance(cm.warning, Warning)

    def check_module_globals(self, module_globals):
        with self.module.catch_warnings(record=True) as w:
            self.module.filterwarnings('default')
            self.module.warn_explicit(
                'eggs', UserWarning, 'bar', 1,
                module_globals=module_globals)
        self.assertEqual(len(w), 1)
        self.assertEqual(w[0].category, UserWarning)
        self.assertEqual(str(w[0].message), 'eggs')

    def check_module_globals_error(self, module_globals, errmsg, errtype=ValueError):
        if self.module is py_warnings:
            self.check_module_globals(module_globals)
            return
        with self.module.catch_warnings(record=True) as w:
            self.module.filterwarnings('always')
            with self.assertRaisesRegex(errtype, re.escape(errmsg)):
                self.module.warn_explicit(
                    'eggs', UserWarning, 'bar', 1,
                    module_globals=module_globals)
        self.assertEqual(len(w), 0)

    def check_module_globals_deprecated(self, module_globals, msg):
        if self.module is py_warnings:
            self.check_module_globals(module_globals)
            return
        with self.module.catch_warnings(record=True) as w:
            self.module.filterwarnings('always')
            self.module.warn_explicit(
                'eggs', UserWarning, 'bar', 1,
                module_globals=module_globals)
        self.assertEqual(len(w), 2)
        self.assertEqual(w[0].category, DeprecationWarning)
        self.assertEqual(str(w[0].message), msg)
        self.assertEqual(w[1].category, UserWarning)
        self.assertEqual(str(w[1].message), 'eggs')

    def test_gh86298_no_loader_and_no_spec(self):
        self.check_module_globals({'__name__': 'bar'})

    def test_gh86298_loader_is_none_and_no_spec(self):
        self.check_module_globals({'__name__': 'bar', '__loader__': None})

    def test_gh86298_no_loader_and_spec_is_none(self):
        self.check_module_globals_error(
            {'__name__': 'bar', '__spec__': None},
            'Module globals is missing a __spec__.loader')

    def test_gh86298_loader_is_none_and_spec_is_none(self):
        self.check_module_globals_error(
            {'__name__': 'bar', '__loader__': None, '__spec__': None},
            'Module globals is missing a __spec__.loader')

    def test_gh86298_loader_is_none_and_spec_loader_is_none(self):
        self.check_module_globals_error(
            {'__name__': 'bar', '__loader__': None,
             '__spec__': types.SimpleNamespace(loader=None)},
            'Module globals is missing a __spec__.loader')

    def test_gh86298_no_spec(self):
        self.check_module_globals_deprecated(
            {'__name__': 'bar', '__loader__': object()},
            'Module globals is missing a __spec__.loader')

    def test_gh86298_spec_is_none(self):
        self.check_module_globals_deprecated(
            {'__name__': 'bar', '__loader__': object(), '__spec__': None},
            'Module globals is missing a __spec__.loader')

    def test_gh86298_no_spec_loader(self):
        self.check_module_globals_deprecated(
            {'__name__': 'bar', '__loader__': object(),
             '__spec__': types.SimpleNamespace()},
            'Module globals is missing a __spec__.loader')

    def test_gh86298_loader_and_spec_loader_disagree(self):
        self.check_module_globals_deprecated(
            {'__name__': 'bar', '__loader__': object(),
             '__spec__': types.SimpleNamespace(loader=object())},
            'Module globals; __loader__ != __spec__.loader')

    def test_gh86298_no_loader_and_no_spec_loader(self):
        self.check_module_globals_error(
            {'__name__': 'bar', '__spec__': types.SimpleNamespace()},
            'Module globals is missing a __spec__.loader', AttributeError)

    def test_gh86298_no_loader_with_spec_loader_okay(self):
        self.check_module_globals(
            {'__name__': 'bar',
             '__spec__': types.SimpleNamespace(loader=object())})

class CWarnTests(WarnTests, unittest.TestCase):
    module = c_warnings

    # As an early adopter, we sanity check the
    # test.import_helper.import_fresh_module utility function
    def test_accelerated(self):
        self.assertIsNot(original_warnings, self.module)
        self.assertNotHasAttr(self.module.warn, '__code__')

class PyWarnTests(WarnTests, unittest.TestCase):
    module = py_warnings

    # As an early adopter, we sanity check the
    # test.import_helper.import_fresh_module utility function
    def test_pure_python(self):
        self.assertIsNot(original_warnings, self.module)
        self.assertHasAttr(self.module.warn, '__code__')


class WCmdLineTests(BaseTest):

    def test_improper_input(self):
        # Uses the private _setoption() function to test the parsing
        # of command-line warning arguments
        with self.module.catch_warnings():
            self.assertRaises(self.module._OptionError,
                              self.module._setoption, '1:2:3:4:5:6')
            self.assertRaises(self.module._OptionError,
                              self.module._setoption, 'bogus::Warning')
            self.assertRaises(self.module._OptionError,
                              self.module._setoption, 'ignore:2::4:-5')
            with self.assertRaises(self.module._OptionError):
                self.module._setoption('ignore::123')
            with self.assertRaises(self.module._OptionError):
                self.module._setoption('ignore::123abc')
            with self.assertRaises(self.module._OptionError):
                self.module._setoption('ignore::===')
            with self.assertRaisesRegex(self.module._OptionError, 'Wärning'):
                self.module._setoption('ignore::Wärning')
            self.module._setoption('error::Warning::0')
            self.assertRaises(UserWarning, self.module.warn, 'convert to error')

    def test_import_from_module(self):
        with self.module.catch_warnings():
            self.module._setoption('ignore::Warning')
            with self.assertRaises(self.module._OptionError):
                self.module._setoption('ignore::TestWarning')
            with self.assertRaises(self.module._OptionError):
                self.module._setoption('ignore::test.test_warnings.bogus')
            self.module._setoption('error::test.test_warnings.TestWarning')
            with self.assertRaises(TestWarning):
                self.module.warn('test warning', TestWarning)


class CWCmdLineTests(WCmdLineTests, unittest.TestCase):
    module = c_warnings


class PyWCmdLineTests(WCmdLineTests, unittest.TestCase):
    module = py_warnings

    def test_improper_option(self):
        # Same as above, but check that the message is printed out when
        # the interpreter is executed. This also checks that options are
        # actually parsed at all.
        rc, out, err = assert_python_ok("-Wxxx", "-c", "pass")
        self.assertIn(b"Invalid -W option ignored: invalid action: 'xxx'", err)

    def test_warnings_bootstrap(self):
        # Check that the warnings module does get loaded when -W<some option>
        # is used (see issue #10372 for an example of silent bootstrap failure).
        rc, out, err = assert_python_ok("-Wi", "-c",
            "import sys; sys.modules['warnings'].warn('foo', RuntimeWarning)")
        # '-Wi' was observed
        self.assertFalse(out.strip())
        self.assertNotIn(b'RuntimeWarning', err)


class _WarningsTests(BaseTest, unittest.TestCase):

    """Tests specific to the _warnings module."""

    module = c_warnings

    def test_filter(self):
        # Everything should function even if 'filters' is not in warnings.
        with self.module.catch_warnings() as w:
            self.module.filterwarnings("error", "", Warning, "", 0)
            self.assertRaises(UserWarning, self.module.warn,
                                'convert to error')
            del self.module.filters
            self.assertRaises(UserWarning, self.module.warn,
                                'convert to error')

    def test_onceregistry(self):
        # Replacing or removing the onceregistry should be okay.
        global __warningregistry__
        message = UserWarning('onceregistry test')
        try:
            original_registry = self.module.onceregistry
            __warningregistry__ = {}
            with self.module.catch_warnings(record=True) as w:
                self.module.resetwarnings()
                self.module.filterwarnings("once", category=UserWarning)
                self.module.warn_explicit(message, UserWarning, "file", 42)
                self.assertEqual(w[-1].message, message)
                del w[:]
                self.module.warn_explicit(message, UserWarning, "file", 42)
                self.assertEqual(len(w), 0)
                # Test the resetting of onceregistry.
                self.module.onceregistry = {}
                __warningregistry__ = {}
                self.module.warn('onceregistry test')
                self.assertEqual(w[-1].message.args, message.args)
                # Removal of onceregistry is okay.
                del w[:]
                del self.module.onceregistry
                __warningregistry__ = {}
                self.module.warn_explicit(message, UserWarning, "file", 42)
                self.assertEqual(len(w), 0)
        finally:
            self.module.onceregistry = original_registry

    def test_default_action(self):
        # Replacing or removing defaultaction should be okay.
        message = UserWarning("defaultaction test")
        original = self.module.defaultaction
        try:
            with self.module.catch_warnings(record=True) as w:
                self.module.resetwarnings()
                registry = {}
                self.module.warn_explicit(message, UserWarning, "<test>", 42,
                                            registry=registry)
                self.assertEqual(w[-1].message, message)
                self.assertEqual(len(w), 1)
                # One actual registry key plus the "version" key
                self.assertEqual(len(registry), 2)
                self.assertIn("version", registry)
                del w[:]
                # Test removal.
                del self.module.defaultaction
                __warningregistry__ = {}
                registry = {}
                self.module.warn_explicit(message, UserWarning, "<test>", 43,
                                            registry=registry)
                self.assertEqual(w[-1].message, message)
                self.assertEqual(len(w), 1)
                self.assertEqual(len(registry), 2)
                del w[:]
                # Test setting.
                self.module.defaultaction = "ignore"
                __warningregistry__ = {}
                registry = {}
                self.module.warn_explicit(message, UserWarning, "<test>", 44,
                                            registry=registry)
                self.assertEqual(len(w), 0)
        finally:
            self.module.defaultaction = original

    def test_showwarning_missing(self):
        # Test that showwarning() missing is okay.
        if self.module._use_context:
            # If _use_context is true, the warnings module does not
            # override/restore showwarning()
            return
        text = 'del showwarning test'
        with self.module.catch_warnings():
            self.module.filterwarnings("always", category=UserWarning)
            del self.module.showwarning
            with support.captured_output('stderr') as stream:
                self.module.warn(text)
                result = stream.getvalue()
        self.assertIn(text, result)

    def test_showwarnmsg_missing(self):
        # Test that _showwarnmsg() missing is okay.
        text = 'del _showwarnmsg test'
        with self.module.catch_warnings():
            self.module.filterwarnings("always", category=UserWarning)

            show = self.module._showwarnmsg
            try:
                del self.module._showwarnmsg
                with support.captured_output('stderr') as stream:
                    self.module.warn(text)
                    result = stream.getvalue()
            finally:
                self.module._showwarnmsg = show
        self.assertIn(text, result)

    def test_showwarning_not_callable(self):
        orig = self.module.showwarning
        try:
            with self.module.catch_warnings():
                self.module.filterwarnings("always", category=UserWarning)
                self.module.showwarning = print
                with support.captured_output('stdout'):
                    self.module.warn('Warning!')
                self.module.showwarning = 23
                self.assertRaises(TypeError, self.module.warn, "Warning!")
        finally:
            self.module.showwarning = orig

    def test_show_warning_output(self):
        # With showwarning() missing, make sure that output is okay.
        orig = self.module.showwarning
        try:
            text = 'test show_warning'
            with self.module.catch_warnings():
                self.module.filterwarnings("always", category=UserWarning)
                del self.module.showwarning
                with support.captured_output('stderr') as stream:
                    warning_tests.inner(text)
                    result = stream.getvalue()
            self.assertEqual(result.count('\n'), 2,
                                 "Too many newlines in %r" % result)
            first_line, second_line = result.split('\n', 1)
            expected_file = os.path.splitext(warning_tests.__file__)[0] + '.py'
            first_line_parts = first_line.rsplit(':', 3)
            path, line, warning_class, message = first_line_parts
            line = int(line)
            self.assertEqual(expected_file, path)
            self.assertEqual(warning_class, ' ' + UserWarning.__name__)
            self.assertEqual(message, ' ' + text)
            expected_line = '  ' + linecache.getline(path, line).strip() + '\n'
            assert expected_line
            self.assertEqual(second_line, expected_line)
        finally:
            self.module.showwarning = orig

    def test_filename_none(self):
        # issue #12467: race condition if a warning is emitted at shutdown
        globals_dict = globals()
        oldfile = globals_dict['__file__']
        try:
            catch = self.module.catch_warnings(record=True)
            with catch as w:
                self.module.filterwarnings("always", category=UserWarning)
                globals_dict['__file__'] = None
                self.module.warn('test', UserWarning)
                self.assertTrue(len(w))
        finally:
            globals_dict['__file__'] = oldfile

    def test_stderr_none(self):
        rc, stdout, stderr = assert_python_ok("-c",
            "import sys; sys.stderr = None; "
            "import warnings; warnings.simplefilter('always'); "
            "warnings.warn('Warning!')")
        self.assertEqual(stdout, b'')
        self.assertNotIn(b'Warning!', stderr)
        self.assertNotIn(b'Error', stderr)

    def test_issue31285(self):
        # warn_explicit() should neither raise a SystemError nor cause an
        # assertion failure, in case the return value of get_source() has a
        # bad splitlines() method.
        get_source_called = []
        def get_module_globals(*, splitlines_ret_val):
            class BadSource(str):
                def splitlines(self):
                    return splitlines_ret_val

            class BadLoader:
                def get_source(self, fullname):
                    get_source_called.append(splitlines_ret_val)
                    return BadSource('spam')

            loader = BadLoader()
            spec = importlib.machinery.ModuleSpec('foobar', loader)
            return {'__loader__': loader,
                    '__spec__': spec,
                    '__name__': 'foobar'}


        wmod = self.module
        with wmod.catch_warnings():
            wmod.filterwarnings('default', category=UserWarning)

            linecache.clearcache()
            with support.captured_stderr() as stderr:
                wmod.warn_explicit(
                    'foo', UserWarning, 'bar', 1,
                    module_globals=get_module_globals(splitlines_ret_val=42))
            self.assertIn('UserWarning: foo', stderr.getvalue())
            self.assertEqual(get_source_called, [42])

            linecache.clearcache()
            with support.swap_attr(wmod, '_showwarnmsg', None):
                del wmod._showwarnmsg
                with support.captured_stderr() as stderr:
                    wmod.warn_explicit(
                        'eggs', UserWarning, 'bar', 1,
                        module_globals=get_module_globals(splitlines_ret_val=[42]))
                self.assertIn('UserWarning: eggs', stderr.getvalue())
            self.assertEqual(get_source_called, [42, [42]])
            linecache.clearcache()

    @support.cpython_only
    def test_issue31411(self):
        # warn_explicit() shouldn't raise a SystemError in case
        # warnings.onceregistry isn't a dictionary.
        wmod = self.module
        with wmod.catch_warnings():
            wmod.filterwarnings('once')
            with support.swap_attr(wmod, 'onceregistry', None):
                with self.assertRaises(TypeError):
                    wmod.warn_explicit('foo', Warning, 'bar', 1, registry=None)

    @support.cpython_only
    def test_issue31416(self):
        # warn_explicit() shouldn't cause an assertion failure in case of a
        # bad warnings.filters or warnings.defaultaction.
        wmod = self.module
        with wmod.catch_warnings():
            wmod._get_filters()[:] = [(None, None, Warning, None, 0)]
            with self.assertRaises(TypeError):
                wmod.warn_explicit('foo', Warning, 'bar', 1)

            wmod._get_filters()[:] = []
            with support.swap_attr(wmod, 'defaultaction', None), \
                 self.assertRaises(TypeError):
                wmod.warn_explicit('foo', Warning, 'bar', 1)

    @support.cpython_only
    def test_issue31566(self):
        # warn() shouldn't cause an assertion failure in case of a bad
        # __name__ global.
        with self.module.catch_warnings():
            self.module.filterwarnings('error', category=UserWarning)
            with support.swap_item(globals(), '__name__', b'foo'), \
                 support.swap_item(globals(), '__file__', None):
                self.assertRaises(UserWarning, self.module.warn, 'bar')


class WarningsDisplayTests(BaseTest):

    """Test the displaying of warnings and the ability to overload functions
    related to displaying warnings."""

    def test_formatwarning(self):
        message = "msg"
        category = Warning
        file_name = os.path.splitext(warning_tests.__file__)[0] + '.py'
        line_num = 5
        file_line = linecache.getline(file_name, line_num).strip()
        format = "%s:%s: %s: %s\n  %s\n"
        expect = format % (file_name, line_num, category.__name__, message,
                            file_line)
        self.assertEqual(expect, self.module.formatwarning(message,
                                                category, file_name, line_num))
        # Test the 'line' argument.
        file_line += " for the win!"
        expect = format % (file_name, line_num, category.__name__, message,
                            file_line)
        self.assertEqual(expect, self.module.formatwarning(message,
                                    category, file_name, line_num, file_line))

    def test_showwarning(self):
        file_name = os.path.splitext(warning_tests.__file__)[0] + '.py'
        line_num = 3
        expected_file_line = linecache.getline(file_name, line_num).strip()
        message = 'msg'
        category = Warning
        file_object = StringIO()
        expect = self.module.formatwarning(message, category, file_name,
                                            line_num)
        self.module.showwarning(message, category, file_name, line_num,
                                file_object)
        self.assertEqual(file_object.getvalue(), expect)
        # Test 'line' argument.
        expected_file_line += "for the win!"
        expect = self.module.formatwarning(message, category, file_name,
                                            line_num, expected_file_line)
        file_object = StringIO()
        self.module.showwarning(message, category, file_name, line_num,
                                file_object, expected_file_line)
        self.assertEqual(expect, file_object.getvalue())

    def test_formatwarning_override(self):
        # bpo-35178: Test that a custom formatwarning function gets the 'line'
        # argument as a positional argument, and not only as a keyword argument
        def myformatwarning(message, category, filename, lineno, text):
            return f'm={message}:c={category}:f={filename}:l={lineno}:t={text}'

        file_name = os.path.splitext(warning_tests.__file__)[0] + '.py'
        line_num = 3
        file_line = linecache.getline(file_name, line_num).strip()
        message = 'msg'
        category = Warning
        file_object = StringIO()
        expected = f'm={message}:c={category}:f={file_name}:l={line_num}' + \
                   f':t={file_line}'
        with support.swap_attr(self.module, 'formatwarning', myformatwarning):
            self.module.showwarning(message, category, file_name, line_num,
                                    file_object, file_line)
            self.assertEqual(file_object.getvalue(), expected)


class CWarningsDisplayTests(WarningsDisplayTests, unittest.TestCase):
    module = c_warnings

class PyWarningsDisplayTests(WarningsDisplayTests, unittest.TestCase):
    module = py_warnings

    def test_tracemalloc(self):
        self.addCleanup(os_helper.unlink, os_helper.TESTFN)

        with open(os_helper.TESTFN, 'w', encoding="utf-8") as fp:
            fp.write(textwrap.dedent("""
                def func():
                    f = open(__file__, "rb")
                    # Emit ResourceWarning
                    f = None

                func()
            """))

        def run(*args):
            res = assert_python_ok(*args, PYTHONIOENCODING='utf-8')
            stderr = res.err.decode('utf-8', 'replace')
            stderr = '\n'.join(stderr.splitlines())

            # normalize newlines
            stderr = re.sub('<.*>', '<...>', stderr)
            return stderr

        # tracemalloc disabled
        filename = os.path.abspath(os_helper.TESTFN)
        stderr = run('-Wd', os_helper.TESTFN)
        expected = textwrap.dedent(f'''
            {filename}:5: ResourceWarning: unclosed file <...>
              f = None
            ResourceWarning: Enable tracemalloc to get the object allocation traceback
        ''').strip()
        self.assertEqual(stderr, expected)

        # tracemalloc enabled
        stderr = run('-Wd', '-X', 'tracemalloc=2', os_helper.TESTFN)
        expected = textwrap.dedent(f'''
            {filename}:5: ResourceWarning: unclosed file <...>
              f = None
            Object allocated at (most recent call last):
              File "{filename}", lineno 7
                func()
              File "{filename}", lineno 3
                f = open(__file__, "rb")
        ''').strip()
        self.assertEqual(stderr, expected)


class CatchWarningTests(BaseTest):

    """Test catch_warnings()."""

    def test_catch_warnings_restore(self):
        if self.module._use_context:
            return  # test disabled if using context vars
        wmod = self.module
        orig_filters = wmod.filters
        orig_showwarning = wmod.showwarning
        # Ensure both showwarning and filters are restored when recording
        with wmod.catch_warnings(record=True):
            wmod.filters = wmod.showwarning = object()
        self.assertIs(wmod.filters, orig_filters)
        self.assertIs(wmod.showwarning, orig_showwarning)
        # Same test, but with recording disabled
        with wmod.catch_warnings(record=False):
            wmod.filters = wmod.showwarning = object()
        self.assertIs(wmod.filters, orig_filters)
        self.assertIs(wmod.showwarning, orig_showwarning)

    def test_catch_warnings_recording(self):
        wmod = self.module
        # Ensure warnings are recorded when requested
        with wmod.catch_warnings(record=True) as w:
            self.assertEqual(w, [])
            self.assertIs(type(w), list)
            wmod.simplefilter("always")
            wmod.warn("foo")
            self.assertEqual(str(w[-1].message), "foo")
            wmod.warn("bar")
            self.assertEqual(str(w[-1].message), "bar")
            self.assertEqual(str(w[0].message), "foo")
            self.assertEqual(str(w[1].message), "bar")
            del w[:]
            self.assertEqual(w, [])
        # Ensure warnings are not recorded when not requested
        orig_showwarning = wmod.showwarning
        with wmod.catch_warnings(record=False) as w:
            self.assertIsNone(w)
            self.assertIs(wmod.showwarning, orig_showwarning)

    def test_catch_warnings_reentry_guard(self):
        wmod = self.module
        # Ensure catch_warnings is protected against incorrect usage
        x = wmod.catch_warnings(record=True)
        self.assertRaises(RuntimeError, x.__exit__)
        with x:
            self.assertRaises(RuntimeError, x.__enter__)
        # Same test, but with recording disabled
        x = wmod.catch_warnings(record=False)
        self.assertRaises(RuntimeError, x.__exit__)
        with x:
            self.assertRaises(RuntimeError, x.__enter__)

    def test_catch_warnings_defaults(self):
        wmod = self.module
        orig_filters = wmod._get_filters()
        orig_showwarning = wmod.showwarning
        # Ensure default behaviour is not to record warnings
        with wmod.catch_warnings() as w:
            self.assertIsNone(w)
            self.assertIs(wmod.showwarning, orig_showwarning)
            self.assertIsNot(wmod._get_filters(), orig_filters)
        self.assertIs(wmod._get_filters(), orig_filters)
        if wmod is sys.modules['warnings']:
            # Ensure the default module is this one
            with wmod.catch_warnings() as w:
                self.assertIsNone(w)
                self.assertIs(wmod.showwarning, orig_showwarning)
                self.assertIsNot(wmod._get_filters(), orig_filters)
            self.assertIs(wmod._get_filters(), orig_filters)

    def test_record_override_showwarning_before(self):
        # Issue #28835: If warnings.showwarning() was overridden, make sure
        # that catch_warnings(record=True) overrides it again.
        if self.module._use_context:
            # If _use_context is true, the warnings module does not restore
            # showwarning()
            return
        text = "This is a warning"
        wmod = self.module
        my_log = []

        def my_logger(message, category, filename, lineno, file=None, line=None):
            nonlocal my_log
            my_log.append(message)

        # Override warnings.showwarning() before calling catch_warnings()
        with support.swap_attr(wmod, 'showwarning', my_logger):
            with wmod.catch_warnings(record=True) as log:
                self.assertIsNot(wmod.showwarning, my_logger)

                wmod.simplefilter("always")
                wmod.warn(text)

            self.assertIs(wmod.showwarning, my_logger)

        self.assertEqual(len(log), 1, log)
        self.assertEqual(log[0].message.args[0], text)
        self.assertEqual(my_log, [])

    def test_record_override_showwarning_inside(self):
        # Issue #28835: It is possible to override warnings.showwarning()
        # in the catch_warnings(record=True) context manager.
        if self.module._use_context:
            # If _use_context is true, the warnings module does not restore
            # showwarning()
            return
        text = "This is a warning"
        wmod = self.module
        my_log = []

        def my_logger(message, category, filename, lineno, file=None, line=None):
            nonlocal my_log
            my_log.append(message)

        with wmod.catch_warnings(record=True) as log:
            wmod.simplefilter("always")
            wmod.showwarning = my_logger
            wmod.warn(text)

        self.assertEqual(len(my_log), 1, my_log)
        self.assertEqual(my_log[0].args[0], text)
        self.assertEqual(log, [])

    def test_check_warnings(self):
        # Explicit tests for the test.support convenience wrapper
        wmod = self.module
        if wmod is not sys.modules['warnings']:
            self.skipTest('module to test is not loaded warnings module')
        with warnings_helper.check_warnings(quiet=False) as w:
            self.assertEqual(w.warnings, [])
            wmod.simplefilter("always")
            wmod.warn("foo")
            self.assertEqual(str(w.message), "foo")
            wmod.warn("bar")
            self.assertEqual(str(w.message), "bar")
            self.assertEqual(str(w.warnings[0].message), "foo")
            self.assertEqual(str(w.warnings[1].message), "bar")
            w.reset()
            self.assertEqual(w.warnings, [])

        with warnings_helper.check_warnings():
            # defaults to quiet=True without argument
            pass
        with warnings_helper.check_warnings(('foo', UserWarning)):
            wmod.warn("foo")

        with self.assertRaises(AssertionError):
            with warnings_helper.check_warnings(('', RuntimeWarning)):
                # defaults to quiet=False with argument
                pass
        with self.assertRaises(AssertionError):
            with warnings_helper.check_warnings(('foo', RuntimeWarning)):
                wmod.warn("foo")

class CCatchWarningTests(CatchWarningTests, unittest.TestCase):
    module = c_warnings

class PyCatchWarningTests(CatchWarningTests, unittest.TestCase):
    module = py_warnings


class EnvironmentVariableTests(BaseTest):

    def test_single_warning(self):
        rc, stdout, stderr = assert_python_ok("-c",
            "import sys; sys.stdout.write(str(sys.warnoptions))",
            PYTHONWARNINGS="ignore::DeprecationWarning",
            PYTHONDEVMODE="")
        self.assertEqual(stdout, b"['ignore::DeprecationWarning']")

    def test_comma_separated_warnings(self):
        rc, stdout, stderr = assert_python_ok("-c",
            "import sys; sys.stdout.write(str(sys.warnoptions))",
            PYTHONWARNINGS="ignore::DeprecationWarning,ignore::UnicodeWarning",
            PYTHONDEVMODE="")
        self.assertEqual(stdout,
            b"['ignore::DeprecationWarning', 'ignore::UnicodeWarning']")

    @force_not_colorized
    def test_envvar_and_command_line(self):
        rc, stdout, stderr = assert_python_ok("-Wignore::UnicodeWarning", "-c",
            "import sys; sys.stdout.write(str(sys.warnoptions))",
            PYTHONWARNINGS="ignore::DeprecationWarning",
            PYTHONDEVMODE="")
        self.assertEqual(stdout,
            b"['ignore::DeprecationWarning', 'ignore::UnicodeWarning']")

    @force_not_colorized
    def test_conflicting_envvar_and_command_line(self):
        rc, stdout, stderr = assert_python_failure("-Werror::DeprecationWarning", "-c",
            "import sys, warnings; sys.stdout.write(str(sys.warnoptions)); "
            "warnings.warn('Message', DeprecationWarning)",
            PYTHONWARNINGS="default::DeprecationWarning",
            PYTHONDEVMODE="")
        self.assertEqual(stdout,
            b"['default::DeprecationWarning', 'error::DeprecationWarning']")
        self.assertEqual(stderr.splitlines(),
            [b"Traceback (most recent call last):",
             b"  File \"<string>\", line 1, in <module>",
             b'    import sys, warnings; sys.stdout.write(str(sys.warnoptions)); warnings.w'
             b"arn('Message', DeprecationWarning)",
             b'                                                                  ~~~~~~~~~~'
             b'~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^',
             b"DeprecationWarning: Message"])

    def test_default_filter_configuration(self):
        pure_python_api = self.module is py_warnings
        if support.Py_DEBUG:
            expected_default_filters = []
        else:
            if pure_python_api:
                main_module_filter = re.compile("__main__")
            else:
                main_module_filter = "__main__"
            expected_default_filters = [
                ('default', None, DeprecationWarning, main_module_filter, 0),
                ('ignore', None, DeprecationWarning, None, 0),
                ('ignore', None, PendingDeprecationWarning, None, 0),
                ('ignore', None, ImportWarning, None, 0),
                ('ignore', None, ResourceWarning, None, 0),
            ]
        expected_output = [str(f).encode() for f in expected_default_filters]

        if pure_python_api:
            # Disable the warnings acceleration module in the subprocess
            code = "import sys; sys.modules.pop('warnings', None); sys.modules['_warnings'] = None; "
        else:
            code = ""
        code += "import warnings; [print(f) for f in warnings._get_filters()]"

        rc, stdout, stderr = assert_python_ok("-c", code, __isolated=True)
        stdout_lines = [line.strip() for line in stdout.splitlines()]
        self.maxDiff = None
        self.assertEqual(stdout_lines, expected_output)


    @unittest.skipUnless(sys.getfilesystemencoding() != 'ascii',
                         'requires non-ascii filesystemencoding')
    def test_nonascii(self):
        PYTHONWARNINGS="ignore:DeprecationWarning" + os_helper.FS_NONASCII
        rc, stdout, stderr = assert_python_ok("-c",
            "import sys; sys.stdout.write(str(sys.warnoptions))",
            PYTHONIOENCODING="utf-8",
            PYTHONWARNINGS=PYTHONWARNINGS,
            PYTHONDEVMODE="")
        self.assertEqual(stdout, str([PYTHONWARNINGS]).encode())

class CEnvironmentVariableTests(EnvironmentVariableTests, unittest.TestCase):
    module = c_warnings

class PyEnvironmentVariableTests(EnvironmentVariableTests, unittest.TestCase):
    module = py_warnings


class LocksTest(unittest.TestCase):
    @support.cpython_only
    @unittest.skipUnless(c_warnings, 'C module is required')
    def test_release_lock_no_lock(self):
        with self.assertRaisesRegex(
            RuntimeError,
            'cannot release un-acquired lock',
        ):
            c_warnings._release_lock()


class _DeprecatedTest(BaseTest, unittest.TestCase):

    """Test _deprecated()."""

    module = original_warnings

    def test_warning(self):
        version = (3, 11, 0, "final", 0)
        test = [(4, 12), (4, 11), (4, 0), (3, 12)]
        for remove in test:
            msg = rf".*test_warnings.*{remove[0]}\.{remove[1]}"
            filter = msg, DeprecationWarning
            with self.subTest(remove=remove):
                with warnings_helper.check_warnings(filter, quiet=False):
                    self.module._deprecated("test_warnings", remove=remove,
                                            _version=version)

        version = (3, 11, 0, "alpha", 0)
        msg = r".*test_warnings.*3\.11"
        with warnings_helper.check_warnings((msg, DeprecationWarning), quiet=False):
            self.module._deprecated("test_warnings", remove=(3, 11),
                                    _version=version)

    def test_RuntimeError(self):
        version = (3, 11, 0, "final", 0)
        test = [(2, 0), (2, 12), (3, 10)]
        for remove in test:
            with self.subTest(remove=remove):
                with self.assertRaises(RuntimeError):
                    self.module._deprecated("test_warnings", remove=remove,
                                            _version=version)
        for level in ["beta", "candidate", "final"]:
            version = (3, 11, 0, level, 0)
            with self.subTest(releaselevel=level):
                with self.assertRaises(RuntimeError):
                    self.module._deprecated("test_warnings", remove=(3, 11),
                                            _version=version)


class BootstrapTest(unittest.TestCase):

    def test_issue_8766(self):
        # "import encodings" emits a warning whereas the warnings is not loaded
        # or not completely loaded (warnings imports indirectly encodings by
        # importing linecache) yet
        with os_helper.temp_cwd() as cwd, os_helper.temp_cwd('encodings'):
            # encodings loaded by initfsencoding()
            assert_python_ok('-c', 'pass', PYTHONPATH=cwd)

            # Use -W to load warnings module at startup
            assert_python_ok('-c', 'pass', '-W', 'always', PYTHONPATH=cwd)


class FinalizationTest(unittest.TestCase):
    def test_finalization(self):
        # Issue #19421: warnings.warn() should not crash
        # during Python finalization
        code = """
import warnings
warn = warnings.warn

class A:
    def __del__(self):
        warn("test")

a=A()
        """
        rc, out, err = assert_python_ok("-c", code)
        self.assertEqual(err.decode().rstrip(),
                         '<string>:7: UserWarning: test')

    def test_late_resource_warning(self):
        # Issue #21925: Emitting a ResourceWarning late during the Python
        # shutdown must be logged.

        expected = b"<sys>:0: ResourceWarning: unclosed file "

        # don't import the warnings module
        # (_warnings will try to import it)
        code = "f = open(%a)" % __file__
        rc, out, err = assert_python_ok("-Wd", "-c", code)
        self.assertStartsWith(err, expected)

        # import the warnings module
        code = "import warnings; f = open(%a)" % __file__
        rc, out, err = assert_python_ok("-Wd", "-c", code)
        self.assertStartsWith(err, expected)


class AsyncTests(BaseTest):
    """Verifies that the catch_warnings() context manager behaves
    as expected when used inside async co-routines.  This requires
    that the context_aware_warnings flag is enabled, so that
    the context manager uses a context variable.
    """

    def setUp(self):
        super().setUp()
        self.module.resetwarnings()

    @unittest.skipIf(not sys.flags.context_aware_warnings,
                     "requires context aware warnings")
    def test_async_context(self):
        import asyncio

        # Events to force the execution interleaving we want.
        step_a1 = asyncio.Event()
        step_a2 = asyncio.Event()
        step_b1 = asyncio.Event()
        step_b2 = asyncio.Event()

        async def run_a():
            with self.module.catch_warnings(record=True) as w:
                await step_a1.wait()
                # The warning emitted here should be caught be the enclosing
                # context manager.
                self.module.warn('run_a warning', UserWarning)
                step_b1.set()
                await step_a2.wait()
                self.assertEqual(len(w), 1)
                self.assertEqual(w[0].message.args[0], 'run_a warning')
                step_b2.set()

        async def run_b():
            with self.module.catch_warnings(record=True) as w:
                step_a1.set()
                await step_b1.wait()
                # The warning emitted here should be caught be the enclosing
                # context manager.
                self.module.warn('run_b warning', UserWarning)
                step_a2.set()
                await step_b2.wait()
                self.assertEqual(len(w), 1)
                self.assertEqual(w[0].message.args[0], 'run_b warning')

        async def run_tasks():
            await asyncio.gather(run_a(), run_b())

        asyncio.run(run_tasks())

    @unittest.skipIf(not sys.flags.context_aware_warnings,
                     "requires context aware warnings")
    def test_async_task_inherit(self):
        """Check that a new asyncio task inherits warnings context from the
        coroutine that spawns it.
        """
        import asyncio

        step1 = asyncio.Event()
        step2 = asyncio.Event()

        async def run_child1():
            await step1.wait()
            # This should be recorded by the run_parent() catch_warnings
            # context.
            self.module.warn('child warning', UserWarning)
            step2.set()

        async def run_child2():
            # This establishes a new catch_warnings() context.  The
            # run_child1() task should still be using the context from
            # run_parent() if context-aware warnings are enabled.
            with self.module.catch_warnings(record=True) as w:
                step1.set()
                await step2.wait()

        async def run_parent():
            with self.module.catch_warnings(record=True) as w:
                await asyncio.gather(run_child1(), run_child2())
                self.assertEqual(len(w), 1)
                self.assertEqual(w[0].message.args[0], 'child warning')

        asyncio.run(run_parent())


class CAsyncTests(AsyncTests, unittest.TestCase):
    module = c_warnings


class PyAsyncTests(AsyncTests, unittest.TestCase):
    module = py_warnings


class ThreadTests(BaseTest):
    """Verifies that the catch_warnings() context manager behaves as
    expected when used within threads.  This requires that both the
    context_aware_warnings flag and thread_inherit_context flags are enabled.
    """

    ENABLE_THREAD_TESTS = (sys.flags.context_aware_warnings and
                           sys.flags.thread_inherit_context)

    def setUp(self):
        super().setUp()
        self.module.resetwarnings()

    @unittest.skipIf(not ENABLE_THREAD_TESTS,
                     "requires thread-safe warnings flags")
    def test_threaded_context(self):
        import threading

        barrier = threading.Barrier(2, timeout=2)

        def run_a():
            with self.module.catch_warnings(record=True) as w:
                barrier.wait()
                # The warning emitted here should be caught be the enclosing
                # context manager.
                self.module.warn('run_a warning', UserWarning)
                barrier.wait()
                self.assertEqual(len(w), 1)
                self.assertEqual(w[0].message.args[0], 'run_a warning')
            # Should be caught be the catch_warnings() context manager of run_threads()
            self.module.warn('main warning', UserWarning)

        def run_b():
            with self.module.catch_warnings(record=True) as w:
                barrier.wait()
                # The warning emitted here should be caught be the enclosing
                # context manager.
                barrier.wait()
                self.module.warn('run_b warning', UserWarning)
                self.assertEqual(len(w), 1)
                self.assertEqual(w[0].message.args[0], 'run_b warning')
            # Should be caught be the catch_warnings() context manager of run_threads()
            self.module.warn('main warning', UserWarning)

        def run_threads():
            threads = [
                threading.Thread(target=run_a),
                threading.Thread(target=run_b),
                ]
            with self.module.catch_warnings(record=True) as w:
                for thread in threads:
                    thread.start()
                for thread in threads:
                    thread.join()
                self.assertEqual(len(w), 2)
                self.assertEqual(w[0].message.args[0], 'main warning')
                self.assertEqual(w[1].message.args[0], 'main warning')

        run_threads()


class CThreadTests(ThreadTests, unittest.TestCase):
    module = c_warnings


class PyThreadTests(ThreadTests, unittest.TestCase):
    module = py_warnings


class DeprecatedTests(PyPublicAPITests):
    def test_dunder_deprecated(self):
        @deprecated("A will go away soon")
        class A:
            pass

        self.assertEqual(A.__deprecated__, "A will go away soon")
        self.assertIsInstance(A, type)

        @deprecated("b will go away soon")
        def b():
            pass

        self.assertEqual(b.__deprecated__, "b will go away soon")
        self.assertIsInstance(b, types.FunctionType)

        @overload
        @deprecated("no more ints")
        def h(x: int) -> int: ...
        @overload
        def h(x: str) -> str: ...
        def h(x):
            return x

        overloads = get_overloads(h)
        self.assertEqual(len(overloads), 2)
        self.assertEqual(overloads[0].__deprecated__, "no more ints")

    def test_class(self):
        @deprecated("A will go away soon")
        class A:
            pass

        with self.assertWarnsRegex(DeprecationWarning, "A will go away soon"):
            A()
        with self.assertWarnsRegex(DeprecationWarning, "A will go away soon"):
            with self.assertRaises(TypeError):
                A(42)

    def test_class_with_init(self):
        @deprecated("HasInit will go away soon")
        class HasInit:
            def __init__(self, x):
                self.x = x

        with self.assertWarnsRegex(DeprecationWarning, "HasInit will go away soon"):
            instance = HasInit(42)
        self.assertEqual(instance.x, 42)

    def test_class_with_new(self):
        has_new_called = False

        @deprecated("HasNew will go away soon")
        class HasNew:
            def __new__(cls, x):
                nonlocal has_new_called
                has_new_called = True
                return super().__new__(cls)

            def __init__(self, x) -> None:
                self.x = x

        with self.assertWarnsRegex(DeprecationWarning, "HasNew will go away soon"):
            instance = HasNew(42)
        self.assertEqual(instance.x, 42)
        self.assertTrue(has_new_called)

    def test_class_with_inherited_new(self):
        new_base_called = False

        class NewBase:
            def __new__(cls, x):
                nonlocal new_base_called
                new_base_called = True
                return super().__new__(cls)

            def __init__(self, x) -> None:
                self.x = x

        @deprecated("HasInheritedNew will go away soon")
        class HasInheritedNew(NewBase):
            pass

        with self.assertWarnsRegex(DeprecationWarning, "HasInheritedNew will go away soon"):
            instance = HasInheritedNew(42)
        self.assertEqual(instance.x, 42)
        self.assertTrue(new_base_called)

    def test_class_with_new_but_no_init(self):
        new_called = False

        @deprecated("HasNewNoInit will go away soon")
        class HasNewNoInit:
            def __new__(cls, x):
                nonlocal new_called
                new_called = True
                obj = super().__new__(cls)
                obj.x = x
                return obj

        with self.assertWarnsRegex(DeprecationWarning, "HasNewNoInit will go away soon"):
            instance = HasNewNoInit(42)
        self.assertEqual(instance.x, 42)
        self.assertTrue(new_called)

    def test_mixin_class(self):
        @deprecated("Mixin will go away soon")
        class Mixin:
            pass

        class Base:
            def __init__(self, a) -> None:
                self.a = a

        with self.assertWarnsRegex(DeprecationWarning, "Mixin will go away soon"):
            class Child(Base, Mixin):
                pass

        instance = Child(42)
        self.assertEqual(instance.a, 42)

    def test_do_not_shadow_user_arguments(self):
        new_called = False
        new_called_cls = None

        @deprecated("MyMeta will go away soon")
        class MyMeta(type):
            def __new__(mcs, name, bases, attrs, cls=None):
                nonlocal new_called, new_called_cls
                new_called = True
                new_called_cls = cls
                return super().__new__(mcs, name, bases, attrs)

        with self.assertWarnsRegex(DeprecationWarning, "MyMeta will go away soon"):
            class Foo(metaclass=MyMeta, cls='haha'):
                pass

        self.assertTrue(new_called)
        self.assertEqual(new_called_cls, 'haha')

    def test_existing_init_subclass(self):
        @deprecated("C will go away soon")
        class C:
            def __init_subclass__(cls) -> None:
                cls.inited = True

        with self.assertWarnsRegex(DeprecationWarning, "C will go away soon"):
            C()

        with self.assertWarnsRegex(DeprecationWarning, "C will go away soon"):
            class D(C):
                pass

        self.assertTrue(D.inited)
        self.assertIsInstance(D(), D)  # no deprecation

    def test_existing_init_subclass_in_base(self):
        class Base:
            def __init_subclass__(cls, x) -> None:
                cls.inited = x

        @deprecated("C will go away soon")
        class C(Base, x=42):
            pass

        self.assertEqual(C.inited, 42)

        with self.assertWarnsRegex(DeprecationWarning, "C will go away soon"):
            C()

        with self.assertWarnsRegex(DeprecationWarning, "C will go away soon"):
            class D(C, x=3):
                pass

        self.assertEqual(D.inited, 3)

    def test_existing_init_subclass_in_sibling_base(self):
        @deprecated("A will go away soon")
        class A:
            pass
        class B:
            def __init_subclass__(cls, x):
                super().__init_subclass__()
                cls.inited = x

        with self.assertWarnsRegex(DeprecationWarning, "A will go away soon"):
            class C(A, B, x=42):
                pass
        self.assertEqual(C.inited, 42)

        with self.assertWarnsRegex(DeprecationWarning, "A will go away soon"):
            class D(B, A, x=42):
                pass
        self.assertEqual(D.inited, 42)

    def test_init_subclass_has_correct_cls(self):
        init_subclass_saw = None

        @deprecated("Base will go away soon")
        class Base:
            def __init_subclass__(cls) -> None:
                nonlocal init_subclass_saw
                init_subclass_saw = cls

        self.assertIsNone(init_subclass_saw)

        with self.assertWarnsRegex(DeprecationWarning, "Base will go away soon"):
            class C(Base):
                pass

        self.assertIs(init_subclass_saw, C)

    def test_init_subclass_with_explicit_classmethod(self):
        init_subclass_saw = None

        @deprecated("Base will go away soon")
        class Base:
            @classmethod
            def __init_subclass__(cls) -> None:
                nonlocal init_subclass_saw
                init_subclass_saw = cls

        self.assertIsNone(init_subclass_saw)

        with self.assertWarnsRegex(DeprecationWarning, "Base will go away soon"):
            class C(Base):
                pass

        self.assertIs(init_subclass_saw, C)

    def test_function(self):
        @deprecated("b will go away soon")
        def b():
            pass

        with self.assertWarnsRegex(DeprecationWarning, "b will go away soon"):
            b()

    def test_method(self):
        class Capybara:
            @deprecated("x will go away soon")
            def x(self):
                pass

        instance = Capybara()
        with self.assertWarnsRegex(DeprecationWarning, "x will go away soon"):
            instance.x()

    def test_property(self):
        class Capybara:
            @property
            @deprecated("x will go away soon")
            def x(self):
                pass

            @property
            def no_more_setting(self):
                return 42

            @no_more_setting.setter
            @deprecated("no more setting")
            def no_more_setting(self, value):
                pass

        instance = Capybara()
        with self.assertWarnsRegex(DeprecationWarning, "x will go away soon"):
            instance.x

        with py_warnings.catch_warnings():
            py_warnings.simplefilter("error")
            self.assertEqual(instance.no_more_setting, 42)

        with self.assertWarnsRegex(DeprecationWarning, "no more setting"):
            instance.no_more_setting = 42

    def test_category(self):
        @deprecated("c will go away soon", category=RuntimeWarning)
        def c():
            pass

        with self.assertWarnsRegex(RuntimeWarning, "c will go away soon"):
            c()

    def test_turn_off_warnings(self):
        @deprecated("d will go away soon", category=None)
        def d():
            pass

        with py_warnings.catch_warnings():
            py_warnings.simplefilter("error")
            d()

    def test_only_strings_allowed(self):
        with self.assertRaisesRegex(
            TypeError,
            "Expected an object of type str for 'message', not 'type'"
        ):
            @deprecated
            class Foo: ...

        with self.assertRaisesRegex(
            TypeError,
            "Expected an object of type str for 'message', not 'function'"
        ):
            @deprecated
            def foo(): ...

    def test_no_retained_references_to_wrapper_instance(self):
        @deprecated('depr')
        def d(): pass

        self.assertFalse(any(
            isinstance(cell.cell_contents, deprecated) for cell in d.__closure__
        ))

    def test_inspect(self):
        @deprecated("depr")
        def sync():
            pass

        @deprecated("depr")
        async def coro():
            pass

        class Cls:
            @deprecated("depr")
            def sync(self):
                pass

            @deprecated("depr")
            async def coro(self):
                pass

        self.assertFalse(inspect.iscoroutinefunction(sync))
        self.assertTrue(inspect.iscoroutinefunction(coro))
        self.assertFalse(inspect.iscoroutinefunction(Cls.sync))
        self.assertTrue(inspect.iscoroutinefunction(Cls.coro))

    def test_inspect_class_signature(self):
        class Cls1:  # no __init__ or __new__
            pass

        class Cls2:  # __new__ only
            def __new__(cls, x, y):
                return super().__new__(cls)

        class Cls3:  # __init__ only
            def __init__(self, x, y):
                pass

        class Cls4:  # __new__ and __init__
            def __new__(cls, x, y):
                return super().__new__(cls)

            def __init__(self, x, y):
                pass

        class Cls5(Cls1):  # inherits no __init__ or __new__
            pass

        class Cls6(Cls2):  # inherits __new__ only
            pass

        class Cls7(Cls3):  # inherits __init__ only
            pass

        class Cls8(Cls4):  # inherits __new__ and __init__
            pass

        # The `@deprecated` decorator will update the class in-place.
        # Test the child classes first.
        for cls in reversed((Cls1, Cls2, Cls3, Cls4, Cls5, Cls6, Cls7, Cls8)):
            with self.subTest(f'class {cls.__name__} signature'):
                try:
                    original_signature = inspect.signature(cls)
                except ValueError:
                    original_signature = None
                try:
                    original_new_signature = inspect.signature(cls.__new__)
                except ValueError:
                    original_new_signature = None

                deprecated_cls = deprecated("depr")(cls)

                try:
                    deprecated_signature = inspect.signature(deprecated_cls)
                except ValueError:
                    deprecated_signature = None
                self.assertEqual(original_signature, deprecated_signature)

                try:
                    deprecated_new_signature = inspect.signature(deprecated_cls.__new__)
                except ValueError:
                    deprecated_new_signature = None
                self.assertEqual(original_new_signature, deprecated_new_signature)


def setUpModule():
    py_warnings.onceregistry.clear()
    c_warnings.onceregistry.clear()


tearDownModule = setUpModule

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