# Source code for _pytest.python

    """Python test discovery, setup and run of test functions."""
    import enum
    import fnmatch
    import inspect
    import itertools
    import os
    import sys
    import types
    import warnings
    from collections import Counter
    from collections import defaultdict
    from functools import partial
    from typing import Any
    from typing import Callable
    from typing import Dict
    from typing import Generator
    from typing import Iterable
    from typing import Iterator
    from typing import List
    from typing import Mapping
    from typing import Optional
    from typing import Sequence
    from typing import Set
    from typing import Tuple
    from typing import Type
    from typing import TYPE_CHECKING
    from typing import Union

    import py

    import _pytest
    from _pytest import fixtures
    from _pytest import nodes
    from _pytest._code import filter_traceback
    from _pytest._code import getfslineno
    from _pytest._code.code import ExceptionInfo
    from _pytest._code.code import TerminalRepr
    from _pytest._io import TerminalWriter
    from _pytest._io.saferepr import saferepr
    from _pytest.compat import ascii_escaped
    from _pytest.compat import final
    from _pytest.compat import get_default_arg_names
    from _pytest.compat import get_real_func
    from _pytest.compat import getimfunc
    from _pytest.compat import getlocation
    from _pytest.compat import is_async_function
    from _pytest.compat import is_generator
    from _pytest.compat import NOTSET
    from _pytest.compat import REGEX_TYPE
    from _pytest.compat import safe_getattr
    from _pytest.compat import safe_isclass
    from _pytest.compat import STRING_TYPES
    from _pytest.config import Config
    from _pytest.config import ExitCode
    from _pytest.config import hookimpl
    from _pytest.config.argparsing import Parser
    from _pytest.deprecated import FSCOLLECTOR_GETHOOKPROXY_ISINITPATH
    from _pytest.fixtures import FuncFixtureInfo
    from _pytest.main import Session
    from _pytest.mark import MARK_GEN
    from _pytest.mark import ParameterSet
    from _pytest.mark.structures import get_unpacked_marks
    from _pytest.mark.structures import Mark
    from _pytest.mark.structures import MarkDecorator
    from _pytest.mark.structures import normalize_mark_list
    from _pytest.outcomes import fail
    from _pytest.outcomes import skip
    from _pytest.pathlib import import_path
    from _pytest.pathlib import ImportPathMismatchError
    from _pytest.pathlib import parts
    from _pytest.pathlib import visit
    from _pytest.warning_types import PytestCollectionWarning
    from _pytest.warning_types import PytestUnhandledCoroutineWarning

    if TYPE_CHECKING:
        from typing_extensions import Literal
        from _pytest.fixtures import _Scope

    def pytest_addoption(parser: Parser) -> None:
        group = parser.getgroup("general")
        group.addoption(
            "--fixtures",
            "--funcargs",
            action="store_true",
            dest="showfixtures",
            default=False,
            help="show available fixtures, sorted by plugin appearance "
            "(fixtures with leading '_' are only shown with '-v')",
        )
        group.addoption(
            "--fixtures-per-test",
            action="store_true",
            dest="show_fixtures_per_test",
            default=False,
            help="show fixtures per test",
        )
        parser.addini(
            "python_files",
            type="args",
            # NOTE: default is also used in AssertionRewritingHook.
            default=["test_*.py", "*_test.py"],
            help="glob-style file patterns for Python test module discovery",
        )
        parser.addini(
            "python_classes",
            type="args",
            default=["Test"],
            help="prefixes or glob names for Python test class discovery",
        )
        parser.addini(
            "python_functions",
            type="args",
            default=["test"],
            help="prefixes or glob names for Python test function and method discovery",
        )
        parser.addini(
            "disable_test_id_escaping_and_forfeit_all_rights_to_community_support",
            type="bool",
            default=False,
            help="disable string escape non-ascii characters, might cause unwanted "
            "side effects(use at your own risk)",
        )

    def pytest_cmdline_main(config: Config) -> Optional[Union[int, ExitCode]]:
        if config.option.showfixtures:
            showfixtures(config)
            return 0
        if config.option.show_fixtures_per_test:
            show_fixtures_per_test(config)
            return 0
        return None

    def pytest_generate_tests(metafunc: "Metafunc") -> None:
        for marker in metafunc.definition.iter_markers(name="parametrize"):
            # TODO: Fix this type-ignore (overlapping kwargs).
            metafunc.parametrize(*marker.args, **marker.kwargs, _param_mark=marker)  # type: ignore[misc]

    def pytest_configure(config: Config) -> None:
        config.addinivalue_line(
            "markers",
            "parametrize(argnames, argvalues): call a test function multiple "
            "times passing in different arguments in turn. argvalues generally "
            "needs to be a list of values if argnames specifies only one name "
            "or a list of tuples of values if argnames specifies multiple names. "
            "Example: @parametrize('arg1', [1,2]) would lead to two calls of the "
            "decorated test function, one with arg1=1 and another with arg1=2."
            "see https://docs.pytest.org/en/stable/parametrize.html for more info "
            "and examples.",
        )
        config.addinivalue_line(
            "markers",
            "usefixtures(fixturename1, fixturename2, ...): mark tests as needing "
            "all of the specified fixtures. see "
            "https://docs.pytest.org/en/stable/fixture.html#usefixtures ",
        )

    def async_warn_and_skip(nodeid: str) -> None:
        msg = "async def functions are not natively supported and have been skipped.\n"
        msg += (
            "You need to install a suitable plugin for your async framework, for example:\n"
        )
        msg += "  - anyio\n"
        msg += "  - pytest-asyncio\n"
        msg += "  - pytest-tornasync\n"
        msg += "  - pytest-trio\n"
        msg += "  - pytest-twisted"
        warnings.warn(PytestUnhandledCoroutineWarning(msg.format(nodeid)))
        skip(msg="async def function and no async plugin installed (see warnings)")

    @hookimpl(trylast=True)
    def pytest_pyfunc_call(pyfuncitem: "Function") -> Optional[object]:
        testfunction = pyfuncitem.obj
        if is_async_function(testfunction):
            async_warn_and_skip(pyfuncitem.nodeid)
        funcargs = pyfuncitem.funcargs
        testargs = {arg: funcargs[arg] for arg in pyfuncitem._fixtureinfo.argnames}
        result = testfunction(**testargs)
        if hasattr(result, "__await__") or hasattr(result, "__aiter__"):
            async_warn_and_skip(pyfuncitem.nodeid)
        return True

    def pytest_collect_file(
        path: py.path.local, parent: nodes.Collector
    ) -> Optional["Module"]:
        ext = path.ext
        if ext == ".py":
            if not parent.session.isinitpath(path):
                if not path_matches_patterns(
                    path, parent.config.getini("python_files") + ["__init__.py"]
                ):
                    return None
            ihook = parent.session.gethookproxy(path)
            module: Module = ihook.pytest_pycollect_makemodule(path=path, parent=parent)
            return module
        return None

    def path_matches_patterns(path: py.path.local, patterns: Iterable[str]) -> bool:
        """Return whether path matches any of the patterns in the list of globs given."""
        return any(path.fnmatch(pattern) for pattern in patterns)

    def pytest_pycollect_makemodule(path: py.path.local, parent) -> "Module":
        if path.basename == "__init__.py":
            pkg: Package = Package.from_parent(parent, fspath=path)
            return pkg
        mod: Module = Module.from_parent(parent, fspath=path)
        return mod

    @hookimpl(trylast=True)
    def pytest_pycollect_makeitem(collector: "PyCollector", name: str, obj: object):
        # Nothing was collected elsewhere, let's do it here.
        if safe_isclass(obj):
            if collector.istestclass(obj, name):
                return Class.from_parent(collector, name=name, obj=obj)
        elif collector.istestfunction(obj, name):
            # mock seems to store unbound methods (issue473), normalize it.
            obj = getattr(obj, "__func__", obj)
            # We need to try and unwrap the function if it's a functools.partial
            # or a functools.wrapped.
            # We mustn't if it's been wrapped with mock.patch (python 2 only).
            if not (inspect.isfunction(obj) or inspect.isfunction(get_real_func(obj))):
                filename, lineno = getfslineno(obj)
                warnings.warn_explicit(
                    message=PytestCollectionWarning(
                        "cannot collect %r because it is not a function." % name
                    ),
                    category=None,
                    filename=str(filename),
                    lineno=lineno + 1,
                )
            elif getattr(obj, "__test__", True):
                if is_generator(obj):
                    res = Function.from_parent(collector, name=name)
                    reason = "yield tests were removed in pytest 4.0 - {name} will be ignored".format(
                        name=name
                    )
                    res.add_marker(MARK_GEN.xfail(run=False, reason=reason))
                    res.warn(PytestCollectionWarning(reason))
                else:
                    res = list(collector._genfunctions(name, obj))
                return res

    class PyobjMixin:
        _ALLOW_MARKERS = True

        # Function and attributes that the mixin needs (for type-checking only).
        if TYPE_CHECKING:
            name: str = ""
            parent: Optional[nodes.Node] = None
            own_markers: List[Mark] = []

            def getparent(self, cls: Type[nodes._NodeType]) -> Optional[nodes._NodeType]:
                ...

            def listchain(self) -> List[nodes.Node]:
                ...

        @property
        def module(self):
            """Python module object this node was collected from (can be None)."""
            node = self.getparent(Module)
            return node.obj if node is not None else None

        @property
        def cls(self):
            """Python class object this node was collected from (can be None)."""
            node = self.getparent(Class)
            return node.obj if node is not None else None

        @property
        def instance(self):
            """Python instance object this node was collected from (can be None)."""
            node = self.getparent(Instance)
            return node.obj if node is not None else None

        @property
        def obj(self):
            """Underlying Python object."""
            obj = getattr(self, "_obj", None)
            if obj is None:
                self._obj = obj = self._getobj()
                # XXX evil hack
                # used to avoid Instance collector marker duplication
                if self._ALLOW_MARKERS:
                    self.own_markers.extend(get_unpacked_marks(self.obj))
            return obj

        @obj.setter
        def obj(self, value):
            self._obj = value

        def _getobj(self):
            """Get the underlying Python object. May be overwritten by subclasses."""
            # TODO: Improve the type of `parent` such that assert/ignore aren't needed.
            assert self.parent is not None
            obj = self.parent.obj  # type: ignore[attr-defined]
            return getattr(obj, self.name)

        def getmodpath(self, stopatmodule: bool = True, includemodule: bool = False) -> str:
            """Return Python path relative to the containing module."""
            chain = self.listchain()
            chain.reverse()
            parts = []
            for node in chain:
                if isinstance(node, Instance):
                    continue
                name = node.name
                if isinstance(node, Module):
                    name = os.path.splitext(name)[0]
                    if stopatmodule:
                        if includemodule:
                            parts.append(name)
                        break
                parts.append(name)
            parts.reverse()
            return ".".join(parts)

        def reportinfo(self) -> Tuple[Union[py.path.local, str], int, str]:
            # XXX caching?
            obj = self.obj
            compat_co_firstlineno = getattr(obj, "compat_co_firstlineno", None)
            if isinstance(compat_co_firstlineno, int):
                # nose compatibility
                file_path = sys.modules[obj.__module__].__file__
                if file_path.endswith(".pyc"):
                    file_path = file_path[:-1]
                fspath: Union[py.path.local, str] = file_path
                lineno = compat_co_firstlineno
            else:
                fspath, lineno = getfslineno(obj)
            modpath = self.getmodpath()
            assert isinstance(lineno, int)
            return fspath, lineno, modpath

    # As an optimization, these builtin attribute names are pre-ignored when
    # iterating over an object during collection -- the pytest_pycollect_makeitem
    # hook is not called for them.
    # fmt: off
    class _EmptyClass: pass  # noqa: E701
    IGNORED_ATTRIBUTES = frozenset.union(  # noqa: E305
        frozenset(),
        # Module.
        dir(types.ModuleType("empty_module")),
        # Some extra module attributes the above doesn't catch.
        {"__builtins__", "__file__", "__cached__"},
        # Class.
        dir(_EmptyClass),
        # Instance.
        dir(_EmptyClass()),
    )
    del _EmptyClass
    # fmt: on

    class PyCollector(PyobjMixin, nodes.Collector):
        def funcnamefilter(self, name: str) -> bool:
            return self._matches_prefix_or_glob_option("python_functions", name)

        def isnosetest(self, obj: object) -> bool:
            """Look for the __test__ attribute, which is applied by the
            @nose.tools.istest decorator.
            """
            # We explicitly check for "is True" here to not mistakenly treat
            # classes with a custom __getattr__ returning something truthy (like a
            # function) as test classes.
            return safe_getattr(obj, "__test__", False) is True

        def classnamefilter(self, name: str) -> bool:
            return self._matches_prefix_or_glob_option("python_classes", name)

        def istestfunction(self, obj: object, name: str) -> bool:
            if self.funcnamefilter(name) or self.isnosetest(obj):
                if isinstance(obj, staticmethod):
                    # staticmethods need to be unwrapped.
                    obj = safe_getattr(obj, "__func__", False)
                return (
                    safe_getattr(obj, "__call__", False)
                    and fixtures.getfixturemarker(obj) is None
                )
            else:
                return False

        def istestclass(self, obj: object, name: str) -> bool:
            return self.classnamefilter(name) or self.isnosetest(obj)

        def _matches_prefix_or_glob_option(self, option_name: str, name: str) -> bool:
            """Check if the given name matches the prefix or glob-pattern defined
            in ini configuration."""
            for option in self.config.getini(option_name):
                if name.startswith(option):
                    return True
                # Check that name looks like a glob-string before calling fnmatch
                # because this is called for every name in each collected module,
                # and fnmatch is somewhat expensive to call.
                elif ("*" in option or "?" in option or "[" in option) and fnmatch.fnmatch(
                    name, option
                ):
                    return True
            return False

        def collect(self) -> Iterable[Union[nodes.Item, nodes.Collector]]:
            if not getattr(self.obj, "__test__", True):
                return []

            # NB. we avoid random getattrs and peek in the __dict__ instead
            # (XXX originally introduced from a PyPy need, still true?)
            dicts = [getattr(self.obj, "__dict__", {})]
            for basecls in self.obj.__class__.__mro__:
                dicts.append(basecls.__dict__)
            seen: Set[str] = set()
            values: List[Union[nodes.Item, nodes.Collector]] = []
            ihook = self.ihook
            for dic in dicts:
                # Note: seems like the dict can change during iteration -
                # be careful not to remove the list() without consideration.
                for name, obj in list(dic.items()):
                    if name in IGNORED_ATTRIBUTES:
                        continue
                    if name in seen:
                        continue
                    seen.add(name)
                    res = ihook.pytest_pycollect_makeitem(
                        collector=self, name=name, obj=obj
                    )
                    if res is None:
                        continue
                    elif isinstance(res, list):
                        values.extend(res)
                    else:
                        values.append(res)

            def sort_key(item):
                fspath, lineno, _ = item.reportinfo()
                return (str(fspath), lineno)

            values.sort(key=sort_key)
            return values

        def _genfunctions(self, name: str, funcobj) -> Iterator["Function"]:
            modulecol = self.getparent(Module)
            assert modulecol is not None
            module = modulecol.obj
            clscol = self.getparent(Class)
            cls = clscol and clscol.obj or None
            fm = self.session._fixturemanager

            definition = FunctionDefinition.from_parent(self, name=name, callobj=funcobj)
            fixtureinfo = definition._fixtureinfo

            metafunc = Metafunc(
                definition, fixtureinfo, self.config, cls=cls, module=module
            )
            methods = []
            if hasattr(module, "pytest_generate_tests"):
                methods.append(module.pytest_generate_tests)
            if cls is not None and hasattr(cls, "pytest_generate_tests"):
                methods.append(cls().pytest_generate_tests)

            self.ihook.pytest_generate_tests.call_extra(methods, dict(metafunc=metafunc))

            if not metafunc._calls:
                yield Function.from_parent(self, name=name, fixtureinfo=fixtureinfo)
            else:
                # Add funcargs() as fixturedefs to fixtureinfo.arg2fixturedefs.
                fixtures.add_funcarg_pseudo_fixture_def(self, metafunc, fm)

                # Add_funcarg_pseudo_fixture_def may have shadowed some fixtures
                # with direct parametrization, so make sure we update what the
                # function really needs.
                fixtureinfo.prune_dependency_tree()

                for callspec in metafunc._calls:
                    subname = f"{name}[{callspec.id}]"
                    yield Function.from_parent(
                        self,
                        name=subname,
                        callspec=callspec,
                        callobj=funcobj,
                        fixtureinfo=fixtureinfo,
                        keywords={callspec.id: True},
                        originalname=name,
                    )

    class Module(nodes.File, PyCollector):
        """Collector for test classes and functions."""

        def _getobj(self):
            return self._importtestmodule()

        def collect(self) -> Iterable[Union[nodes.Item, nodes.Collector]]:
            self._inject_setup_module_fixture()
            self._inject_setup_function_fixture()
            self.session._fixturemanager.parsefactories(self)
            return super().collect()

        def _inject_setup_module_fixture(self) -> None:
            """Inject a hidden autouse, module scoped fixture into the collected module object
            that invokes setUpModule/tearDownModule if either or both are available.

            Using a fixture to invoke this methods ensures we play nicely and unsurprisingly with
            other fixtures (#517).
            """
            setup_module = _get_first_non_fixture_func(
                self.obj, ("setUpModule", "setup_module")
            )
            teardown_module = _get_first_non_fixture_func(
                self.obj, ("tearDownModule", "teardown_module")
            )

            if setup_module is None and teardown_module is None:
                return

            @fixtures.fixture(
                autouse=True,
                scope="module",
                # Use a unique name to speed up lookup.
                name=f"xunit_setup_module_fixture_{self.obj.__name__}",
            )
            def xunit_setup_module_fixture(request) -> Generator[None, None, None]:
                if setup_module is not None:
                    _call_with_optional_argument(setup_module, request.module)
                yield
                if teardown_module is not None:
                    _call_with_optional_argument(teardown_module, request.module)

            self.obj.__pytest_setup_module = xunit_setup_module_fixture

        def _inject_setup_function_fixture(self) -> None:
            """Inject a hidden autouse, function scoped fixture into the collected module object
            that invokes setup_function/teardown_function if either or both are available.

            Using a fixture to invoke this methods ensures we play nicely and unsurprisingly with
            other fixtures (#517).
            """
            setup_function = _get_first_non_fixture_func(self.obj, ("setup_function",))
            teardown_function = _get_first_non_fixture_func(
                self.obj, ("teardown_function",)
            )
            if setup_function is None and teardown_function is None:
                return

            @fixtures.fixture(
                autouse=True,
                scope="function",
                # Use a unique name to speed up lookup.
                name=f"xunit_setup_function_fixture_{self.obj.__name__}",
            )
            def xunit_setup_function_fixture(request) -> Generator[None, None, None]:
                if request.instance is not None:
                    # in this case we are bound to an instance, so we need to let
                    # setup_method handle this
                    yield
                    return
                if setup_function is not None:
                    _call_with_optional_argument(setup_function, request.function)
                yield
                if teardown_function is not None:
                    _call_with_optional_argument(teardown_function, request.function)

            self.obj.__pytest_setup_function = xunit_setup_function_fixture

        def _importtestmodule(self):
            # We assume we are only called once per module.
            importmode = self.config.getoption("--import-mode")
            try:
                mod = import_path(self.fspath, mode=importmode)
            except SyntaxError as e:
                raise self.CollectError(
                    ExceptionInfo.from_current().getrepr(style="short")
                ) from e
            except ImportPathMismatchError as e:
                raise self.CollectError(
                    "import file mismatch:\n"
                    "imported module %r has this __file__ attribute:\n"
                    "  %s\n"
                    "which is not the same as the test file we want to collect:\n"
                    "  %s\n"
                    "HINT: remove __pycache__ / .pyc files and/or use a "
                    "unique basename for your test file modules" % e.args
                ) from e
            except ImportError as e:
                exc_info = ExceptionInfo.from_current()
                if self.config.getoption("verbose") < 2:
                    exc_info.traceback = exc_info.traceback.filter(filter_traceback)
                exc_repr = (
                    exc_info.getrepr(style="short")
                    if exc_info.traceback
                    else exc_info.exconly()
                )
                formatted_tb = str(exc_repr)
                raise self.CollectError(
                    "ImportError while importing test module '{fspath}'.\n"
                    "Hint: make sure your test modules/packages have valid Python names.\n"
                    "Traceback:\n"
                    "{traceback}".format(fspath=self.fspath, traceback=formatted_tb)
                ) from e
            except skip.Exception as e:
                if e.allow_module_level:
                    raise
                raise self.CollectError(
                    "Using pytest.skip outside of a test is not allowed. "
                    "To decorate a test function, use the @pytest.mark.skip "
                    "or @pytest.mark.skipif decorators instead, and to skip a "
                    "module use `pytestmark = pytest.mark.{skip,skipif}."
                ) from e
            self.config.pluginmanager.consider_module(mod)
            return mod

    class Package(Module):
        def __init__(
            self,
            fspath: py.path.local,
            parent: nodes.Collector,
            # NOTE: following args are unused:
            config=None,
            session=None,
            nodeid=None,
        ) -> None:
            # NOTE: Could be just the following, but kept as-is for compat.
            # nodes.FSCollector.__init__(self, fspath, parent=parent)
            session = parent.session
            nodes.FSCollector.__init__(
                self, fspath, parent=parent, config=config, session=session, nodeid=nodeid
            )
            self.name = os.path.basename(str(fspath.dirname))

        def setup(self) -> None:
            # Not using fixtures to call setup_module here because autouse fixtures
            # from packages are not called automatically (#4085).
            setup_module = _get_first_non_fixture_func(
                self.obj, ("setUpModule", "setup_module")
            )
            if setup_module is not None:
                _call_with_optional_argument(setup_module, self.obj)

            teardown_module = _get_first_non_fixture_func(
                self.obj, ("tearDownModule", "teardown_module")
            )
            if teardown_module is not None:
                func = partial(_call_with_optional_argument, teardown_module, self.obj)
                self.addfinalizer(func)

        def gethookproxy(self, fspath: py.path.local):
            warnings.warn(FSCOLLECTOR_GETHOOKPROXY_ISINITPATH, stacklevel=2)
            return self.session.gethookproxy(fspath)

        def isinitpath(self, path: py.path.local) -> bool:
            warnings.warn(FSCOLLECTOR_GETHOOKPROXY_ISINITPATH, stacklevel=2)
            return self.session.isinitpath(path)

        def _recurse(self, direntry: "os.DirEntry[str]") -> bool:
            if direntry.name == "__pycache__":
                return False
            path = py.path.local(direntry.path)
            ihook = self.session.gethookproxy(path.dirpath())
            if ihook.pytest_ignore_collect(path=path, config=self.config):
                return False
            norecursepatterns = self.config.getini("norecursedirs")
            if any(path.check(fnmatch=pat) for pat in norecursepatterns):
                return False
            return True

        def _collectfile(
            self, path: py.path.local, handle_dupes: bool = True
        ) -> Sequence[nodes.Collector]:
            assert (
                path.isfile()
            ), "{!r} is not a file (isdir={!r}, exists={!r}, islink={!r})".format(
                path, path.isdir(), path.exists(), path.islink()
            )
            ihook = self.session.gethookproxy(path)
            if not self.session.isinitpath(path):
                if ihook.pytest_ignore_collect(path=path, config=self.config):
                    return ()

            if handle_dupes:
                keepduplicates = self.config.getoption("keepduplicates")
                if not keepduplicates:
                    duplicate_paths = self.config.pluginmanager._duplicatepaths
                    if path in duplicate_paths:
                        return ()
                    else:
                        duplicate_paths.add(path)

            return ihook.pytest_collect_file(path=path, parent=self)  # type: ignore[no-any-return]

        def collect(self) -> Iterable[Union[nodes.Item, nodes.Collector]]:
            this_path = self.fspath.dirpath()
            init_module = this_path.join("__init__.py")
            if init_module.check(file=1) and path_matches_patterns(
                init_module, self.config.getini("python_files")
            ):
                yield Module.from_parent(self, fspath=init_module)
            pkg_prefixes: Set[py.path.local] = set()
            for direntry in visit(str(this_path), recurse=self._recurse):
                path = py.path.local(direntry.path)

                # We will visit our own __init__.py file, in which case we skip it.
                if direntry.is_file():
                    if direntry.name == "__init__.py" and path.dirpath() == this_path:
                        continue

                parts_ = parts(direntry.path)
                if any(
                    str(pkg_prefix) in parts_ and pkg_prefix.join("__init__.py") != path
                    for pkg_prefix in pkg_prefixes
                ):
                    continue

                if direntry.is_file():
                    yield from self._collectfile(path)
                elif not direntry.is_dir():
                    # Broken symlink or invalid/missing file.
                    continue
                elif path.join("__init__.py").check(file=1):
                    pkg_prefixes.add(path)

    def _call_with_optional_argument(func, arg) -> None:
        """Call the given function with the given argument if func accepts one argument, otherwise
        calls func without arguments."""
        arg_count = func.__code__.co_argcount
        if inspect.ismethod(func):
            arg_count -= 1
        if arg_count:
            func(arg)
        else:
            func()

    def _get_first_non_fixture_func(obj: object, names: Iterable[str]):
        """Return the attribute from the given object to be used as a setup/teardown
        xunit-style function, but only if not marked as a fixture to avoid calling it twice."""
        for name in names:
            meth = getattr(obj, name, None)
            if meth is not None and fixtures.getfixturemarker(meth) is None:
                return meth

    class Class(PyCollector):
        """Collector for test methods."""

        @classmethod
        def from_parent(cls, parent, *, name, obj=None):
            """The public constructor."""
            return super().from_parent(name=name, parent=parent)

        def collect(self) -> Iterable[Union[nodes.Item, nodes.Collector]]:
            if not safe_getattr(self.obj, "__test__", True):
                return []
            if hasinit(self.obj):
                assert self.parent is not None
                self.warn(
                    PytestCollectionWarning(
                        "cannot collect test class %r because it has a "
                        "__init__ constructor (from: %s)"
                        % (self.obj.__name__, self.parent.nodeid)
                    )
                )
                return []
            elif hasnew(self.obj):
                assert self.parent is not None
                self.warn(
                    PytestCollectionWarning(
                        "cannot collect test class %r because it has a "
                        "__new__ constructor (from: %s)"
                        % (self.obj.__name__, self.parent.nodeid)
                    )
                )
                return []

            self._inject_setup_class_fixture()
            self._inject_setup_method_fixture()

            return [Instance.from_parent(self, name="()")]

        def _inject_setup_class_fixture(self) -> None:
            """Inject a hidden autouse, class scoped fixture into the collected class object
            that invokes setup_class/teardown_class if either or both are available.

            Using a fixture to invoke this methods ensures we play nicely and unsurprisingly with
            other fixtures (#517).
            """
            setup_class = _get_first_non_fixture_func(self.obj, ("setup_class",))
            teardown_class = getattr(self.obj, "teardown_class", None)
            if setup_class is None and teardown_class is None:
                return

            @fixtures.fixture(
                autouse=True,
                scope="class",
                # Use a unique name to speed up lookup.
                name=f"xunit_setup_class_fixture_{self.obj.__qualname__}",
            )
            def xunit_setup_class_fixture(cls) -> Generator[None, None, None]:
                if setup_class is not None:
                    func = getimfunc(setup_class)
                    _call_with_optional_argument(func, self.obj)
                yield
                if teardown_class is not None:
                    func = getimfunc(teardown_class)
                    _call_with_optional_argument(func, self.obj)

            self.obj.__pytest_setup_class = xunit_setup_class_fixture

        def _inject_setup_method_fixture(self) -> None:
            """Inject a hidden autouse, function scoped fixture into the collected class object
            that invokes setup_method/teardown_method if either or both are available.

            Using a fixture to invoke this methods ensures we play nicely and unsurprisingly with
            other fixtures (#517).
            """
            setup_method = _get_first_non_fixture_func(self.obj, ("setup_method",))
            teardown_method = getattr(self.obj, "teardown_method", None)
            if setup_method is None and teardown_method is None:
                return

            @fixtures.fixture(
                autouse=True,
                scope="function",
                # Use a unique name to speed up lookup.
                name=f"xunit_setup_method_fixture_{self.obj.__qualname__}",
            )
            def xunit_setup_method_fixture(self, request) -> Generator[None, None, None]:
                method = request.function
                if setup_method is not None:
                    func = getattr(self, "setup_method")
                    _call_with_optional_argument(func, method)
                yield
                if teardown_method is not None:
                    func = getattr(self, "teardown_method")
                    _call_with_optional_argument(func, method)

            self.obj.__pytest_setup_method = xunit_setup_method_fixture

    class Instance(PyCollector):
        _ALLOW_MARKERS = False  # hack, destroy later
        # Instances share the object with their parents in a way
        # that duplicates markers instances if not taken out
        # can be removed at node structure reorganization time.

        def _getobj(self):
            # TODO: Improve the type of `parent` such that assert/ignore aren't needed.
            assert self.parent is not None
            obj = self.parent.obj  # type: ignore[attr-defined]
            return obj()

        def collect(self) -> Iterable[Union[nodes.Item, nodes.Collector]]:
            self.session._fixturemanager.parsefactories(self)
            return super().collect()

        def newinstance(self):
            self.obj = self._getobj()
            return self.obj

    def hasinit(obj: object) -> bool:
        init: object = getattr(obj, "__init__", None)
        if init:
            return init != object.__init__
        return False

    def hasnew(obj: object) -> bool:
        new: object = getattr(obj, "__new__", None)
        if new:
            return new != object.__new__
        return False

    @final
    class CallSpec2:
        def __init__(self, metafunc: "Metafunc") -> None:
            self.metafunc = metafunc
            self.funcargs: Dict[str, object] = {}
            self._idlist: List[str] = []
            self.params: Dict[str, object] = {}
            # Used for sorting parametrized resources.
            self._arg2scopenum: Dict[str, int] = {}
            self.marks: List[Mark] = []
            self.indices: Dict[str, int] = {}

        def copy(self) -> "CallSpec2":
            cs = CallSpec2(self.metafunc)
            cs.funcargs.update(self.funcargs)
            cs.params.update(self.params)
            cs.marks.extend(self.marks)
            cs.indices.update(self.indices)
            cs._arg2scopenum.update(self._arg2scopenum)
            cs._idlist = list(self._idlist)
            return cs

        def _checkargnotcontained(self, arg: str) -> None:
            if arg in self.params or arg in self.funcargs:
                raise ValueError(f"duplicate {arg!r}")

        def getparam(self, name: str) -> object:
            try:
                return self.params[name]
            except KeyError as e:
                raise ValueError(name) from e

        @property
        def id(self) -> str:
            return "-".join(map(str, self._idlist))

        def setmulti2(
            self,
            valtypes: Mapping[str, "Literal['params', 'funcargs']"],
            argnames: Sequence[str],
            valset: Iterable[object],
            id: str,
            marks: Iterable[Union[Mark, MarkDecorator]],
            scopenum: int,
            param_index: int,
        ) -> None:
            for arg, val in zip(argnames, valset):
                self._checkargnotcontained(arg)
                valtype_for_arg = valtypes[arg]
                if valtype_for_arg == "params":
                    self.params[arg] = val
                elif valtype_for_arg == "funcargs":
                    self.funcargs[arg] = val
                else:  # pragma: no cover
                    assert False, f"Unhandled valtype for arg: {valtype_for_arg}"
                self.indices[arg] = param_index
                self._arg2scopenum[arg] = scopenum
            self._idlist.append(id)
            self.marks.extend(normalize_mark_list(marks))

    @final
    class Metafunc:
        """Objects passed to the :func:`pytest_generate_tests <_pytest.hookspec.pytest_generate_tests>` hook.

        They help to inspect a test function and to generate tests according to
        test configuration or values specified in the class or module where a
        test function is defined.
        """

        def __init__(
            self,
            definition: "FunctionDefinition",
            fixtureinfo: fixtures.FuncFixtureInfo,
            config: Config,
            cls=None,
            module=None,
        ) -> None:
            #: Access to the underlying :class:`_pytest.python.FunctionDefinition`.
            self.definition = definition

            #: Access to the :class:`_pytest.config.Config` object for the test session.
            self.config = config

            #: The module object where the test function is defined in.
            self.module = module

            #: Underlying Python test function.
            self.function = definition.obj

            #: Set of fixture names required by the test function.
            self.fixturenames = fixtureinfo.names_closure

            #: Class object where the test function is defined in or ``None``.
            self.cls = cls

            self._calls: List[CallSpec2] = []
            self._arg2fixturedefs = fixtureinfo.name2fixturedefs

        def parametrize(
            self,
            argnames: Union[str, List[str], Tuple[str, ...]],
            argvalues: Iterable[Union[ParameterSet, Sequence[object], object]],
            indirect: Union[bool, Sequence[str]] = False,
            ids: Optional[
                Union[
                    Iterable[Union[None, str, float, int, bool]],
                    Callable[[Any], Optional[object]],
                ]
            ] = None,
            scope: "Optional[_Scope]" = None,
            *,
            _param_mark: Optional[Mark] = None,
        ) -> None:
            """Add new invocations to the underlying test function using the list
            of argvalues for the given argnames.  Parametrization is performed
            during the collection phase.  If you need to setup expensive resources
            see about setting indirect to do it rather at test setup time.

            :param argnames:
                A comma-separated string denoting one or more argument names, or
                a list/tuple of argument strings.

            :param argvalues:
                The list of argvalues determines how often a test is invoked with
                different argument values.

                If only one argname was specified argvalues is a list of values.
                If N argnames were specified, argvalues must be a list of
                N-tuples, where each tuple-element specifies a value for its
                respective argname.

            :param indirect:
                A list of arguments' names (subset of argnames) or a boolean.
                If True the list contains all names from the argnames. Each
                argvalue corresponding to an argname in this list will
                be passed as request.param to its respective argname fixture
                function so that it can perform more expensive setups during the
                setup phase of a test rather than at collection time.

            :param ids:
                Sequence of (or generator for) ids for ``argvalues``,
                or a callable to return part of the id for each argvalue.

                With sequences (and generators like ``itertools.count()``) the
                returned ids should be of type ``string``, ``int``, ``float``,
                ``bool``, or ``None``.
                They are mapped to the corresponding index in ``argvalues``.
                ``None`` means to use the auto-generated id.

                If it is a callable it will be called for each entry in
                ``argvalues``, and the return value is used as part of the
                auto-generated id for the whole set (where parts are joined with
                dashes ("-")).
                This is useful to provide more specific ids for certain items, e.g.
                dates.  Returning ``None`` will use an auto-generated id.

                If no ids are provided they will be generated automatically from
                the argvalues.

            :param scope:
                If specified it denotes the scope of the parameters.
                The scope is used for grouping tests by parameter instances.
                It will also override any fixture-function defined scope, allowing
                to set a dynamic scope using test context or configuration.
            """
            from _pytest.fixtures import scope2index

            argnames, parameters = ParameterSet._for_parametrize(
                argnames,
                argvalues,
                self.function,
                self.config,
                nodeid=self.definition.nodeid,
            )
            del argvalues

            if "request" in argnames:
                fail(
                    "'request' is a reserved name and cannot be used in @pytest.mark.parametrize",
                    pytrace=False,
                )

            if scope is None:
                scope = _find_parametrized_scope(argnames, self._arg2fixturedefs, indirect)

            self._validate_if_using_arg_names(argnames, indirect)

            arg_values_types = self._resolve_arg_value_types(argnames, indirect)

            # Use any already (possibly) generated ids with parametrize Marks.
            if _param_mark and _param_mark._param_ids_from:
                generated_ids = _param_mark._param_ids_from._param_ids_generated
                if generated_ids is not None:
                    ids = generated_ids

            ids = self._resolve_arg_ids(
                argnames, ids, parameters, nodeid=self.definition.nodeid
            )

            # Store used (possibly generated) ids with parametrize Marks.
            if _param_mark and _param_mark._param_ids_from and generated_ids is None:
                object.__setattr__(_param_mark._param_ids_from, "_param_ids_generated", ids)

            scopenum = scope2index(
                scope, descr=f"parametrize() call in {self.function.__name__}"
            )

            # Create the new calls: if we are parametrize() multiple times (by applying the decorator
            # more than once) then we accumulate those calls generating the cartesian product
            # of all calls.
            newcalls = []
            for callspec in self._calls or [CallSpec2(self)]:
                for param_index, (param_id, param_set) in enumerate(zip(ids, parameters)):
                    newcallspec = callspec.copy()
                    newcallspec.setmulti2(
                        arg_values_types,
                        argnames,
                        param_set.values,
                        param_id,
                        param_set.marks,
                        scopenum,
                        param_index,
                    )
                    newcalls.append(newcallspec)
            self._calls = newcalls

        def _resolve_arg_ids(
            self,
            argnames: Sequence[str],
            ids: Optional[
                Union[
                    Iterable[Union[None, str, float, int, bool]],
                    Callable[[Any], Optional[object]],
                ]
            ],
            parameters: Sequence[ParameterSet],
            nodeid: str,
        ) -> List[str]:
            """Resolve the actual ids for the given argnames, based on the ``ids`` parameter given
            to ``parametrize``.

            :param List[str] argnames: List of argument names passed to ``parametrize()``.
            :param ids: The ids parameter of the parametrized call (see docs).
            :param List[ParameterSet] parameters: The list of parameter values, same size as ``argnames``.
            :param str str: The nodeid of the item that generated this parametrized call.
            :rtype: List[str]
            :returns: The list of ids for each argname given.
            """
            if ids is None:
                idfn = None
                ids_ = None
            elif callable(ids):
                idfn = ids
                ids_ = None
            else:
                idfn = None
                ids_ = self._validate_ids(ids, parameters, self.function.__name__)
            return idmaker(argnames, parameters, idfn, ids_, self.config, nodeid=nodeid)

        def _validate_ids(
            self,
            ids: Iterable[Union[None, str, float, int, bool]],
            parameters: Sequence[ParameterSet],
            func_name: str,
        ) -> List[Union[None, str]]:
            try:
                num_ids = len(ids)  # type: ignore[arg-type]
            except TypeError:
                try:
                    iter(ids)
                except TypeError as e:
                    raise TypeError("ids must be a callable or an iterable") from e
                num_ids = len(parameters)

            # num_ids == 0 is a special case: https://github.com/pytest-dev/pytest/issues/1849
            if num_ids != len(parameters) and num_ids != 0:
                msg = "In {}: {} parameter sets specified, with different number of ids: {}"
                fail(msg.format(func_name, len(parameters), num_ids), pytrace=False)

            new_ids = []
            for idx, id_value in enumerate(itertools.islice(ids, num_ids)):
                if id_value is None or isinstance(id_value, str):
                    new_ids.append(id_value)
                elif isinstance(id_value, (float, int, bool)):
                    new_ids.append(str(id_value))
                else:
                    msg = (  # type: ignore[unreachable]
                        "In {}: ids must be list of string/float/int/bool, "
                        "found: {} (type: {!r}) at index {}"
                    )
                    fail(
                        msg.format(func_name, saferepr(id_value), type(id_value), idx),
                        pytrace=False,
                    )
            return new_ids

        def _resolve_arg_value_types(
            self, argnames: Sequence[str], indirect: Union[bool, Sequence[str]],
        ) -> Dict[str, "Literal['params', 'funcargs']"]:
            """Resolve if each parametrized argument must be considered a
            parameter to a fixture or a "funcarg" to the function, based on the
            ``indirect`` parameter of the parametrized() call.

            :param List[str] argnames: List of argument names passed to ``parametrize()``.
            :param indirect: Same as the ``indirect`` parameter of ``parametrize()``.
            :rtype: Dict[str, str]
                A dict mapping each arg name to either:
                * "params" if the argname should be the parameter of a fixture of the same name.
                * "funcargs" if the argname should be a parameter to the parametrized test function.
            """
            if isinstance(indirect, bool):
                valtypes: Dict[str, Literal["params", "funcargs"]] = dict.fromkeys(
                    argnames, "params" if indirect else "funcargs"
                )
            elif isinstance(indirect, Sequence):
                valtypes = dict.fromkeys(argnames, "funcargs")
                for arg in indirect:
                    if arg not in argnames:
                        fail(
                            "In {}: indirect fixture '{}' doesn't exist".format(
                                self.function.__name__, arg
                            ),
                            pytrace=False,
                        )
                    valtypes[arg] = "params"
            else:
                fail(
                    "In {func}: expected Sequence or boolean for indirect, got {type}".format(
                        type=type(indirect).__name__, func=self.function.__name__
                    ),
                    pytrace=False,
                )
            return valtypes

        def _validate_if_using_arg_names(
            self, argnames: Sequence[str], indirect: Union[bool, Sequence[str]],
        ) -> None:
            """Check if all argnames are being used, by default values, or directly/indirectly.

            :param List[str] argnames: List of argument names passed to ``parametrize()``.
            :param indirect: Same as the ``indirect`` parameter of ``parametrize()``.
            :raises ValueError: If validation fails.
            """
            default_arg_names = set(get_default_arg_names(self.function))
            func_name = self.function.__name__
            for arg in argnames:
                if arg not in self.fixturenames:
                    if arg in default_arg_names:
                        fail(
                            "In {}: function already takes an argument '{}' with a default value".format(
                                func_name, arg
                            ),
                            pytrace=False,
                        )
                    else:
                        if isinstance(indirect, Sequence):
                            name = "fixture" if arg in indirect else "argument"
                        else:
                            name = "fixture" if indirect else "argument"
                        fail(
                            f"In {func_name}: function uses no {name} '{arg}'",
                            pytrace=False,
                        )

    def _find_parametrized_scope(
        argnames: Sequence[str],
        arg2fixturedefs: Mapping[str, Sequence[fixtures.FixtureDef[object]]],
        indirect: Union[bool, Sequence[str]],
    ) -> "fixtures._Scope":
        """Find the most appropriate scope for a parametrized call based on its arguments.

        When there's at least one direct argument, always use "function" scope.

        When a test function is parametrized and all its arguments are indirect
        (e.g. fixtures), return the most narrow scope based on the fixtures used.

        Related to issue #1832, based on code posted by @Kingdread.
        """
        if isinstance(indirect, Sequence):
            all_arguments_are_fixtures = len(indirect) == len(argnames)
        else:
            all_arguments_are_fixtures = bool(indirect)

        if all_arguments_are_fixtures:
            fixturedefs = arg2fixturedefs or {}
            used_scopes = [
                fixturedef[0].scope
                for name, fixturedef in fixturedefs.items()
                if name in argnames
            ]
            if used_scopes:
                # Takes the most narrow scope from used fixtures.
                for scope in reversed(fixtures.scopes):
                    if scope in used_scopes:
                        return scope

        return "function"

    def _ascii_escaped_by_config(val: Union[str, bytes], config: Optional[Config]) -> str:
        if config is None:
            escape_option = False
        else:
            escape_option = config.getini(
                "disable_test_id_escaping_and_forfeit_all_rights_to_community_support"
            )
        # TODO: If escaping is turned off and the user passes bytes,
        #       will return a bytes. For now we ignore this but the
        #       code *probably* doesn't handle this case.
        return val if escape_option else ascii_escaped(val)  # type: ignore

    def _idval(
        val: object,
        argname: str,
        idx: int,
        idfn: Optional[Callable[[Any], Optional[object]]],
        nodeid: Optional[str],
        config: Optional[Config],
    ) -> str:
        if idfn:
            try:
                generated_id = idfn(val)
                if generated_id is not None:
                    val = generated_id
            except Exception as e:
                prefix = f"{nodeid}: " if nodeid is not None else ""
                msg = "error raised while trying to determine id of parameter '{}' at position {}"
                msg = prefix + msg.format(argname, idx)
                raise ValueError(msg) from e
        elif config:
            hook_id: Optional[str] = config.hook.pytest_make_parametrize_id(
                config=config, val=val, argname=argname
            )
            if hook_id:
                return hook_id

        if isinstance(val, STRING_TYPES):
            return _ascii_escaped_by_config(val, config)
        elif val is None or isinstance(val, (float, int, bool)):
            return str(val)
        elif isinstance(val, REGEX_TYPE):
            return ascii_escaped(val.pattern)
        elif val is NOTSET:
            # Fallback to default. Note that NOTSET is an enum.Enum.
            pass
        elif isinstance(val, enum.Enum):
            return str(val)
        elif isinstance(getattr(val, "__name__", None), str):
            # Name of a class, function, module, etc.
            name: str = getattr(val, "__name__")
            return name
        return str(argname) + str(idx)

    def _idvalset(
        idx: int,
        parameterset: ParameterSet,
        argnames: Iterable[str],
        idfn: Optional[Callable[[Any], Optional[object]]],
        ids: Optional[List[Union[None, str]]],
        nodeid: Optional[str],
        config: Optional[Config],
    ) -> str:
        if parameterset.id is not None:
            return parameterset.id
        id = None if ids is None or idx >= len(ids) else ids[idx]
        if id is None:
            this_id = [
                _idval(val, argname, idx, idfn, nodeid=nodeid, config=config)
                for val, argname in zip(parameterset.values, argnames)
            ]
            return "-".join(this_id)
        else:
            return _ascii_escaped_by_config(id, config)

    def idmaker(
        argnames: Iterable[str],
        parametersets: Iterable[ParameterSet],
        idfn: Optional[Callable[[Any], Optional[object]]] = None,
        ids: Optional[List[Union[None, str]]] = None,
        config: Optional[Config] = None,
        nodeid: Optional[str] = None,
    ) -> List[str]:
        resolved_ids = [
            _idvalset(
                valindex, parameterset, argnames, idfn, ids, config=config, nodeid=nodeid
            )
            for valindex, parameterset in enumerate(parametersets)
        ]

        # All IDs must be unique!
        unique_ids = set(resolved_ids)
        if len(unique_ids) != len(resolved_ids):

            # Record the number of occurrences of each test ID.
            test_id_counts = Counter(resolved_ids)

            # Map the test ID to its next suffix.
            test_id_suffixes: Dict[str, int] = defaultdict(int)

            # Suffix non-unique IDs to make them unique.
            for index, test_id in enumerate(resolved_ids):
                if test_id_counts[test_id] > 1:
                    resolved_ids[index] = "{}{}".format(test_id, test_id_suffixes[test_id])
                    test_id_suffixes[test_id] += 1

        return resolved_ids

    def show_fixtures_per_test(config):
        from _pytest.main import wrap_session

        return wrap_session(config, _show_fixtures_per_test)

    def _show_fixtures_per_test(config: Config, session: Session) -> None:
        import _pytest.config

        session.perform_collect()
        curdir = py.path.local()
        tw = _pytest.config.create_terminal_writer(config)
        verbose = config.getvalue("verbose")

        def get_best_relpath(func):
            loc = getlocation(func, str(curdir))
            return curdir.bestrelpath(py.path.local(loc))

        def write_fixture(fixture_def: fixtures.FixtureDef[object]) -> None:
            argname = fixture_def.argname
            if verbose <= 0 and argname.startswith("_"):
                return
            if verbose > 0:
                bestrel = get_best_relpath(fixture_def.func)
                funcargspec = f"{argname} -- {bestrel}"
            else:
                funcargspec = argname
            tw.line(funcargspec, green=True)
            fixture_doc = inspect.getdoc(fixture_def.func)
            if fixture_doc:
                write_docstring(tw, fixture_doc)
            else:
                tw.line("    no docstring available", red=True)

        def write_item(item: nodes.Item) -> None:
            # Not all items have _fixtureinfo attribute.
            info: Optional[FuncFixtureInfo] = getattr(item, "_fixtureinfo", None)
            if info is None or not info.name2fixturedefs:
                # This test item does not use any fixtures.
                return
            tw.line()
            tw.sep("-", f"fixtures used by {item.name}")
            # TODO: Fix this type ignore.
            tw.sep("-", "({})".format(get_best_relpath(item.function)))  # type: ignore[attr-defined]
            # dict key not used in loop but needed for sorting.
            for _, fixturedefs in sorted(info.name2fixturedefs.items()):
                assert fixturedefs is not None
                if not fixturedefs:
                    continue
                # Last item is expected to be the one used by the test item.
                write_fixture(fixturedefs[-1])

        for session_item in session.items:
            write_item(session_item)

    def showfixtures(config: Config) -> Union[int, ExitCode]:
        from _pytest.main import wrap_session

        return wrap_session(config, _showfixtures_main)

    def _showfixtures_main(config: Config, session: Session) -> None:
        import _pytest.config

        session.perform_collect()
        curdir = py.path.local()
        tw = _pytest.config.create_terminal_writer(config)
        verbose = config.getvalue("verbose")

        fm = session._fixturemanager

        available = []
        seen: Set[Tuple[str, str]] = set()

        for argname, fixturedefs in fm._arg2fixturedefs.items():
            assert fixturedefs is not None
            if not fixturedefs:
                continue
            for fixturedef in fixturedefs:
                loc = getlocation(fixturedef.func, str(curdir))
                if (fixturedef.argname, loc) in seen:
                    continue
                seen.add((fixturedef.argname, loc))
                available.append(
                    (
                        len(fixturedef.baseid),
                        fixturedef.func.__module__,
                        curdir.bestrelpath(py.path.local(loc)),
                        fixturedef.argname,
                        fixturedef,
                    )
                )

        available.sort()
        currentmodule = None
        for baseid, module, bestrel, argname, fixturedef in available:
            if currentmodule != module:
                if not module.startswith("_pytest."):
                    tw.line()
                    tw.sep("-", f"fixtures defined from {module}")
                    currentmodule = module
            if verbose <= 0 and argname[0] == "_":
                continue
            tw.write(argname, green=True)
            if fixturedef.scope != "function":
                tw.write(" [%s scope]" % fixturedef.scope, cyan=True)
            if verbose > 0:
                tw.write(" -- %s" % bestrel, yellow=True)
            tw.write("\n")
            loc = getlocation(fixturedef.func, str(curdir))
            doc = inspect.getdoc(fixturedef.func)
            if doc:
                write_docstring(tw, doc)
            else:
                tw.line(f"    {loc}: no docstring available", red=True)
            tw.line()

    def write_docstring(tw: TerminalWriter, doc: str, indent: str = "    ") -> None:
        for line in doc.split("\n"):
            tw.line(indent + line)

    class Function(PyobjMixin, nodes.Item):
        """An Item responsible for setting up and executing a Python test function.

        param name:
            The full function name, including any decorations like those
            added by parametrization (``my_func[my_param]``).
        param parent:
            The parent Node.
        param config:
            The pytest Config object.
        param callspec:
            If given, this is function has been parametrized and the callspec contains
            meta information about the parametrization.
        param callobj:
            If given, the object which will be called when the Function is invoked,
            otherwise the callobj will be obtained from ``parent`` using ``originalname``.
        param keywords:
            Keywords bound to the function object for "-k" matching.
        param session:
            The pytest Session object.
        param fixtureinfo:
            Fixture information already resolved at this fixture node..
        param originalname:
            The attribute name to use for accessing the underlying function object.
            Defaults to ``name``. Set this if name is different from the original name,
            for example when it contains decorations like those added by parametrization
            (``my_func[my_param]``).
        """

        # Disable since functions handle it themselves.
        _ALLOW_MARKERS = False

        def __init__(
            self,
            name: str,
            parent,
            config: Optional[Config] = None,
            callspec: Optional[CallSpec2] = None,
            callobj=NOTSET,
            keywords=None,
            session: Optional[Session] = None,
            fixtureinfo: Optional[FuncFixtureInfo] = None,
            originalname: Optional[str] = None,
        ) -> None:
            super().__init__(name, parent, config=config, session=session)

            if callobj is not NOTSET:
                self.obj = callobj

            #: Original function name, without any decorations (for example
            #: parametrization adds a ``"[...]"`` suffix to function names), used to access
            #: the underlying function object from ``parent`` (in case ``callobj`` is not given
            #: explicitly).
            #:
            #: .. versionadded:: 3.0
            self.originalname = originalname or name

            # Note: when FunctionDefinition is introduced, we should change ``originalname``
            # to a readonly property that returns FunctionDefinition.name.

            self.keywords.update(self.obj.__dict__)
            self.own_markers.extend(get_unpacked_marks(self.obj))
            if callspec:
                self.callspec = callspec
                # this is total hostile and a mess
                # keywords are broken by design by now
                # this will be redeemed later
                for mark in callspec.marks:
                    # feel free to cry, this was broken for years before
                    # and keywords cant fix it per design
                    self.keywords[mark.name] = mark
                self.own_markers.extend(normalize_mark_list(callspec.marks))
            if keywords:
                self.keywords.update(keywords)

            # todo: this is a hell of a hack
            # https://github.com/pytest-dev/pytest/issues/4569

            self.keywords.update(
                {
                    mark.name: True
                    for mark in self.iter_markers()
                    if mark.name not in self.keywords
                }
            )

            if fixtureinfo is None:
                fixtureinfo = self.session._fixturemanager.getfixtureinfo(
                    self, self.obj, self.cls, funcargs=True
                )
            self._fixtureinfo: FuncFixtureInfo = fixtureinfo
            self.fixturenames = fixtureinfo.names_closure
            self._initrequest()

        @classmethod
        def from_parent(cls, parent, **kw):  # todo: determine sound type limitations
            """The public constructor."""
            return super().from_parent(parent=parent, **kw)

        def _initrequest(self) -> None:
            self.funcargs: Dict[str, object] = {}
            self._request = fixtures.FixtureRequest(self, _ispytest=True)

        @property
        def function(self):
            """Underlying python 'function' object."""
            return getimfunc(self.obj)

        def _getobj(self):
            assert self.parent is not None
            return getattr(self.parent.obj, self.originalname)  # type: ignore[attr-defined]

        @property
        def _pyfuncitem(self):
            """(compatonly) for code expecting pytest-2.2 style request objects."""
            return self

        def runtest(self) -> None:
            """Execute the underlying test function."""
            self.ihook.pytest_pyfunc_call(pyfuncitem=self)

        def setup(self) -> None:
            if isinstance(self.parent, Instance):
                self.parent.newinstance()
                self.obj = self._getobj()
            self._request._fillfixtures()

        def _prunetraceback(self, excinfo: ExceptionInfo[BaseException]) -> None:
            if hasattr(self, "_obj") and not self.config.getoption("fulltrace", False):
                code = _pytest._code.Code.from_function(get_real_func(self.obj))
                path, firstlineno = code.path, code.firstlineno
                traceback = excinfo.traceback
                ntraceback = traceback.cut(path=path, firstlineno=firstlineno)
                if ntraceback == traceback:
                    ntraceback = ntraceback.cut(path=path)
                    if ntraceback == traceback:
                        ntraceback = ntraceback.filter(filter_traceback)
                        if not ntraceback:
                            ntraceback = traceback

                excinfo.traceback = ntraceback.filter()
                # issue364: mark all but first and last frames to
                # only show a single-line message for each frame.
                if self.config.getoption("tbstyle", "auto") == "auto":
                    if len(excinfo.traceback) > 2:
                        for entry in excinfo.traceback[1:-1]:
                            entry.set_repr_style("short")

        # TODO: Type ignored -- breaks Liskov Substitution.
        def repr_failure(  # type: ignore[override]
            self, excinfo: ExceptionInfo[BaseException],
        ) -> Union[str, TerminalRepr]:
            style = self.config.getoption("tbstyle", "auto")
            if style == "auto":
                style = "long"
            return self._repr_failure_py(excinfo, style=style)

    class FunctionDefinition(Function):
        """
        This class is a step gap solution until we evolve to have actual function definition nodes
        and manage to get rid of ``metafunc``.
        """

        def runtest(self) -> None:
            raise RuntimeError("function definitions are not supposed to be run as tests")

        setup = runtest