""" Python test discovery, setup and run of test functions. """
import enum
import fnmatch
import inspect
import itertools
import os
import sys
import typing
import warnings
from collections import Counter
from collections import defaultdict
from collections.abc import Sequence
from functools import partial
from typing import Callable
from typing import Dict
from typing import Iterable
from typing import List
from typing import Optional
from typing import Tuple
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.code import ExceptionInfo
from _pytest._code.source import getfslineno
from _pytest._io import TerminalWriter
from _pytest._io.saferepr import saferepr
from _pytest.compat import ascii_escaped
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 hookimpl
from _pytest.deprecated import FUNCARGNAMES
from _pytest.fixtures import FuncFixtureInfo
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 normalize_mark_list
from _pytest.outcomes import fail
from _pytest.outcomes import skip
from _pytest.pathlib import parts
from _pytest.warning_types import PytestCollectionWarning
from _pytest.warning_types import PytestUnhandledCoroutineWarning


def pyobj_property(name):
    def get(self):
        node = self.getparent(getattr(__import__("pytest"), name))
        if node is not None:
            return node.obj

    doc = "python {} object this node was collected from (can be None).".format(
        name.lower()
    )
    return property(get, None, None, doc)


def pytest_addoption(parser):
    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)",
    )

    group.addoption(
        "--import-mode",
        default="prepend",
        choices=["prepend", "append"],
        dest="importmode",
        help="prepend/append to sys.path when importing test modules, "
        "default is to prepend.",
    )


def pytest_cmdline_main(config):
    if config.option.showfixtures:
        showfixtures(config)
        return 0
    if config.option.show_fixtures_per_test:
        show_fixtures_per_test(config)
        return 0


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] # noqa: F821


def pytest_configure(config):
    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/latest/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/latest/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 += "  - pytest-asyncio\n"
    msg += "  - pytest-trio\n"
    msg += "  - pytest-tornasync\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"):
    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, parent):
    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
        ihook = parent.session.gethookproxy(path)
        return ihook.pytest_pycollect_makemodule(path=path, parent=parent)


def path_matches_patterns(path, patterns):
    """Returns True if the given py.path.local matches one of the patterns in the list of globs given"""
    return any(path.fnmatch(pattern) for pattern in patterns)


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


@hookimpl(hookwrapper=True)
def pytest_pycollect_makeitem(collector, name, obj):
    outcome = yield
    res = outcome.get_result()
    if res is not None:
        return
    # nothing was collected elsewhere, let's do it here
    if safe_isclass(obj):
        if collector.istestclass(obj, name):
            outcome.force_result(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))
            outcome.force_result(res)


class PyobjMixin:
    module = pyobj_property("Module")
    cls = pyobj_property("Class")
    instance = pyobj_property("Instance")
    _ALLOW_MARKERS = True

    @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):
        """Gets the underlying Python object. May be overwritten by subclasses."""
        return getattr(self.parent.obj, self.name)

    def getmodpath(self, stopatmodule=True, includemodule=False):
        """ 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 = file_path  # type: Union[py.path.local, str]
            lineno = compat_co_firstlineno
        else:
            fspath, lineno = getfslineno(obj)
        modpath = self.getmodpath()
        assert isinstance(lineno, int)
        return fspath, lineno, modpath


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

    def isnosetest(self, obj):
        """ 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):
        return self._matches_prefix_or_glob_option("python_classes", name)

    def istestfunction(self, obj, name):
        if self.funcnamefilter(name) or self.isnosetest(obj):
            if isinstance(obj, staticmethod):
                # static methods 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, name):
        return self.classnamefilter(name) or self.isnosetest(obj)

    def _matches_prefix_or_glob_option(self, option_name, name):
        """
        checks 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):
        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 inspect.getmro(self.obj.__class__):
            dicts.append(basecls.__dict__)
        seen = {}
        values = []
        for dic in dicts:
            for name, obj in list(dic.items()):
                if name in seen:
                    continue
                seen[name] = True
                res = self._makeitem(name, obj)
                if res is None:
                    continue
                if not isinstance(res, list):
                    res = [res]
                values.extend(res)

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

        values.sort(key=sort_key)
        return values

    def _makeitem(self, name, obj):
        # assert self.ihook.fspath == self.fspath, self
        return self.ihook.pytest_pycollect_makeitem(collector=self, name=name, obj=obj)

    def _genfunctions(self, name, funcobj):
        module = self.getparent(Module).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 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 = "{}[{}]".format(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):
        self._inject_setup_module_fixture()
        self._inject_setup_function_fixture()
        self.session._fixturemanager.parsefactories(self)
        return super().collect()

    def _inject_setup_module_fixture(self):
        """Injects 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")
        def xunit_setup_module_fixture(request):
            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):
        """Injects 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")
        def xunit_setup_function_fixture(request):
            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 = self.fspath.pyimport(ensuresyspath=importmode)
        except SyntaxError:
            raise self.CollectError(ExceptionInfo.from_current().getrepr(style="short"))
        except self.fspath.ImportMismatchError 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
            )
        except ImportError:
            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)
            )
        except _pytest.runner.Skipped 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}."
            )
        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 = fspath.dirname

    def setup(self):
        # 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):
        return super()._gethookproxy(fspath)

    def isinitpath(self, path):
        return path in self.session._initialpaths

    def collect(self):
        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()
        for path in this_path.visit(rec=self._recurse, bf=True, sort=True):
            # We will visit our own __init__.py file, in which case we skip it.
            is_file = path.isfile()
            if is_file:
                if path.basename == "__init__.py" and path.dirpath() == this_path:
                    continue

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

            if is_file:
                yield from self._collectfile(path)
            elif not path.isdir():
                # 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):
    """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, names):
    """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):
        if not safe_getattr(self.obj, "__test__", True):
            return []
        if hasinit(self.obj):
            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):
            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):
        """Injects 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")
        def xunit_setup_class_fixture(cls):
            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):
        """Injects 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")
        def xunit_setup_method_fixture(self, request):
            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):
        return self.parent.obj()

    def collect(self):
        self.session._fixturemanager.parsefactories(self)
        return super().collect()

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


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


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


class CallSpec2:
    def __init__(self, metafunc):
        self.metafunc = metafunc
        self.funcargs = {}
        self._idlist = []
        self.params = {}
        self._arg2scopenum = {}  # used for sorting parametrized resources
        self.marks = []
        self.indices = {}

    def copy(self):
        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):
        if arg in self.params or arg in self.funcargs:
            raise ValueError("duplicate {!r}".format(arg))

    def getparam(self, name):
        try:
            return self.params[name]
        except KeyError:
            raise ValueError(name)

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

    def setmulti2(self, valtypes, argnames, valset, id, marks, scopenum, param_index):
        for arg, val in zip(argnames, valset):
            self._checkargnotcontained(arg)
            valtype_for_arg = valtypes[arg]
            getattr(self, valtype_for_arg)[arg] = val
            self.indices[arg] = param_index
            self._arg2scopenum[arg] = scopenum
        self._idlist.append(id)
        self.marks.extend(normalize_mark_list(marks))


class Metafunc:
    """
    Metafunc objects are 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:
        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 = []  # type: List[CallSpec2]
        self._arg2fixturedefs = fixtureinfo.name2fixturedefs

    @property
    def funcargnames(self):
        """ alias attribute for ``fixturenames`` for pre-2.3 compatibility"""
        warnings.warn(FUNCARGNAMES, stacklevel=2)
        return self.fixturenames

    def parametrize(
        self,
        argnames: Union[str, List[str], Tuple[str, ...]],
        argvalues: Iterable[Union[ParameterSet, typing.Sequence[object], object]],
        indirect: Union[bool, typing.Sequence[str]] = False,
        ids: Optional[
            Union[
                Iterable[Union[None, str, float, int, bool]],
                Callable[[object], Optional[object]],
            ]
        ] = None,
        scope: "Optional[str]" = 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.

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

        :arg 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.

        :arg indirect: The list of argnames or boolean. A list of arguments'
            names (subset of argnames). 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.

        :arg 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.

        :arg 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,
            function_definition=self.definition,
        )
        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, item=self.definition)

        # 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="parametrize() call in {}".format(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: typing.Sequence[str],
        ids: Optional[
            Union[
                Iterable[Union[None, str, float, int, bool]],
                Callable[[object], Optional[object]],
            ]
        ],
        parameters: typing.Sequence[ParameterSet],
        item,
    ) -> List[str]:
        """Resolves 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 Item item: the item that generated this parametrized call.
        :rtype: List[str]
        :return: 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, item=item)

    def _validate_ids(
        self,
        ids: Iterable[Union[None, str, float, int, bool]],
        parameters: typing.Sequence[ParameterSet],
        func_name: str,
    ) -> List[Union[None, str]]:
        try:
            num_ids = len(ids)  # type: ignore[arg-type] # noqa: F821
        except TypeError:
            try:
                iter(ids)
            except TypeError:
                raise TypeError("ids must be a callable or an iterable")
            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 = "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: typing.Sequence[str],
        indirect: Union[bool, typing.Sequence[str]],
    ) -> Dict[str, str]:
        """Resolves 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 ``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.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: typing.Sequence[str],
        indirect: Union[bool, typing.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 ``indirect`` parameter of ``parametrize()``.
        :raise 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(
                        "In {}: function uses no {} '{}'".format(func_name, name, arg),
                        pytrace=False,
                    )


def _find_parametrized_scope(argnames, arg2fixturedefs, indirect):
    """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.
    """
    from _pytest.fixtures import scopes

    if isinstance(indirect, (list, tuple)):
        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(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[[object], Optional[object]]],
    item,
    config: Optional[Config],
) -> str:
    if idfn:
        try:
            generated_id = idfn(val)
            if generated_id is not None:
                val = generated_id
        except Exception as e:
            msg = "{}: error raised while trying to determine id of parameter '{}' at position {}"
            msg = msg.format(item.nodeid, argname, idx)
            raise ValueError(msg) from e
    elif config:
        hook_id = config.hook.pytest_make_parametrize_id(
            config=config, val=val, argname=argname
        )  # type: Optional[str]
        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 isinstance(val, enum.Enum):
        return str(val)
    elif isinstance(getattr(val, "__name__", None), str):
        # name of a class, function, module, etc.
        name = getattr(val, "__name__")  # type: str
        return name
    return str(argname) + str(idx)


def _idvalset(
    idx: int,
    parameterset: ParameterSet,
    argnames: Iterable[str],
    idfn: Optional[Callable[[object], Optional[object]]],
    ids: Optional[List[Union[None, str]]],
    item,
    config: Optional[Config],
):
    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, item=item, 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[[object], Optional[object]]] = None,
    ids: Optional[List[Union[None, str]]] = None,
    config: Optional[Config] = None,
    item=None,
) -> List[str]:
    resolved_ids = [
        _idvalset(valindex, parameterset, argnames, idfn, ids, config=config, item=item)
        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 = defaultdict(int)  # type: Dict[str, 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, session):
    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, curdir)
        return curdir.bestrelpath(loc)

    def write_fixture(fixture_def):
        argname = fixture_def.argname
        if verbose <= 0 and argname.startswith("_"):
            return
        if verbose > 0:
            bestrel = get_best_relpath(fixture_def.func)
            funcargspec = "{} -- {}".format(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):
        try:
            info = item._fixtureinfo
        except AttributeError:
            # doctests items have no _fixtureinfo attribute
            return
        if not info.name2fixturedefs:
            # this test item does not use any fixtures
            return
        tw.line()
        tw.sep("-", "fixtures used by {}".format(item.name))
        tw.sep("-", "({})".format(get_best_relpath(item.function)))
        # 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):
    from _pytest.main import wrap_session

    return wrap_session(config, _showfixtures_main)


def _showfixtures_main(config, session):
    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()

    for argname, fixturedefs in fm._arg2fixturedefs.items():
        assert fixturedefs is not None
        if not fixturedefs:
            continue
        for fixturedef in fixturedefs:
            loc = getlocation(fixturedef.func, curdir)
            if (fixturedef.argname, loc) in seen:
                continue
            seen.add((fixturedef.argname, loc))
            available.append(
                (
                    len(fixturedef.baseid),
                    fixturedef.func.__module__,
                    curdir.bestrelpath(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("-", "fixtures defined from {}".format(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, curdir)
        doc = inspect.getdoc(fixturedef.func)
        if doc:
            write_docstring(tw, doc)
        else:
            tw.line("    {}: no docstring available".format(loc), red=True)
        tw.line()


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


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

    # disable since functions handle it themselves
    _ALLOW_MARKERS = False

    def __init__(
        self,
        name,
        parent,
        args=None,
        config=None,
        callspec: Optional[CallSpec2] = None,
        callobj=NOTSET,
        keywords=None,
        session=None,
        fixtureinfo: Optional[FuncFixtureInfo] = None,
        originalname=None,
    ) -> None:
        super().__init__(name, parent, config=config, session=session)
        self._args = args
        if callobj is not NOTSET:
            self.obj = callobj

        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 = fixtureinfo  # type: FuncFixtureInfo
        self.fixturenames = fixtureinfo.names_closure
        self._initrequest()

        #: original function name, without any decorations (for example
        #: parametrization adds a ``"[...]"`` suffix to function names).
        #:
        #: .. versionadded:: 3.0
        self.originalname = originalname

    @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):
        self.funcargs = {}
        self._request = fixtures.FixtureRequest(self)

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

    def _getobj(self):
        name = self.name
        i = name.find("[")  # parametrization
        if i != -1:
            name = name[:i]
        return getattr(self.parent.obj, name)

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

    @property
    def funcargnames(self):
        """ alias attribute for ``fixturenames`` for pre-2.3 compatibility"""
        warnings.warn(FUNCARGNAMES, stacklevel=2)
        return self.fixturenames

    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()
        fixtures.fillfixtures(self)

    def _prunetraceback(self, excinfo: ExceptionInfo) -> None:
        if hasattr(self, "_obj") and not self.config.getoption("fulltrace", False):
            code = _pytest._code.Code(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")

    def repr_failure(self, excinfo, outerr=None):
        assert outerr is None, "XXX outerr usage is deprecated"
        style = self.config.getoption("tbstyle", "auto")
        if style == "auto":
            style = "long"
        return self._repr_failure_py(excinfo, style=style)


class FunctionDefinition(Function):
    """
    internal hack until we get actual definition nodes instead of the
    crappy metafunc hack
    """

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

    setup = runtest
