Question

import os
import warnings
from pathlib import Path
from typing import Callable
from typing import Iterable
from typing import Iterator
from typing import List
from typing import Optional
from typing import overload
from typing import Set
from typing import Tuple
from typing import Type
from typing import TYPE_CHECKING
from typing import TypeVar
from typing import Union

import py

import _pytest._code
from _pytest._code import getfslineno
from _pytest._code.code import ExceptionInfo
from _pytest._code.code import TerminalRepr
from _pytest.compat import cached_property
from _pytest.config import Config
from _pytest.config import ConftestImportFailure
from _pytest.deprecated import FSCOLLECTOR_GETHOOKPROXY_ISINITPATH
from _pytest.mark.structures import Mark
from _pytest.mark.structures import MarkDecorator
from _pytest.mark.structures import NodeKeywords
from _pytest.outcomes import fail
from _pytest.pathlib import absolutepath
from _pytest.store import Store

if TYPE_CHECKING:
    # Imported here due to circular import.
    from _pytest.main import Session
    from _pytest._code.code import _TracebackStyle


SEP = "/"

tracebackcutdir = py.path.local(_pytest.__file__).dirpath()


def iterparentnodeids(nodeid: str) -> Iterator[str]:
    """Return the parent node IDs of a given node ID, inclusive.

    For the node ID

        "testing/code/test_excinfo.py::TestFormattedExcinfo::test_repr_source"

    the result would be

        ""
        "testing"
        "testing/code"
        "testing/code/test_excinfo.py"
        "testing/code/test_excinfo.py::TestFormattedExcinfo"
        "testing/code/test_excinfo.py::TestFormattedExcinfo::test_repr_source"

    Note that :: parts are only considered at the last / component.
    """
    pos = 0
    sep = SEP
    yield ""
    while True:
        at = nodeid.find(sep, pos)
        if at == -1 and sep == SEP:
            sep = "::"
        elif at == -1:
            if nodeid:
                yield nodeid
            break
        else:
            if at:
                yield nodeid[:at]
            pos = at + len(sep)


_NodeType = TypeVar("_NodeType", bound="Node")


class NodeMeta(type):
    def __call__(self, *k, **kw):
        msg = (
            "Direct construction of {name} has been deprecated, please use {name}.from_parent.\n"
            "See "
            "https://docs.pytest.org/en/stable/deprecations.html#node-construction-changed-to-node-from-parent"
            " for more details."
        ).format(name=self.__name__)
        fail(msg, pytrace=False)

    def _create(self, *k, **kw):
        return super().__call__(*k, **kw)


[文档]class Node(metaclass=NodeMeta):
    """Base class for Collector and Item, the components of the test
    collection tree.

    Collector subclasses have children; Items are leaf nodes.
    """

    # Use __slots__ to make attribute access faster.
    # Note that __dict__ is still available.
    __slots__ = (
        "name",
        "parent",
        "config",
        "session",
        "fspath",
        "_nodeid",
        "_store",
        "__dict__",
    )

    def __init__(
        self,
        name: str,
        parent: "Optional[Node]" = None,
        config: Optional[Config] = None,
        session: "Optional[Session]" = None,
        fspath: Optional[py.path.local] = None,
        nodeid: Optional[str] = None,
    ) -> None:
        #: A unique name within the scope of the parent node.
        self.name = name

        #: The parent collector node.
        self.parent = parent

        #: The pytest config object.
        if config:
            self.config: Config = config
        else:
            if not parent:
                raise TypeError("config or parent must be provided")
            self.config = parent.config

        #: The pytest session this node is part of.
        if session:
            self.session = session
        else:
            if not parent:
                raise TypeError("session or parent must be provided")
            self.session = parent.session

        #: Filesystem path where this node was collected from (can be None).
        self.fspath = fspath or getattr(parent, "fspath", None)

        #: Keywords/markers collected from all scopes.
        self.keywords = NodeKeywords(self)

        #: The marker objects belonging to this node.
        self.own_markers: List[Mark] = []

        #: Allow adding of extra keywords to use for matching.
        self.extra_keyword_matches: Set[str] = set()

        if nodeid is not None:
            assert "::()" not in nodeid
            self._nodeid = nodeid
        else:
            if not self.parent:
                raise TypeError("nodeid or parent must be provided")
            self._nodeid = self.parent.nodeid
            if self.name != "()":
                self._nodeid += "::" + self.name

        # A place where plugins can store information on the node for their
        # own use. Currently only intended for internal plugins.
        self._store = Store()

[文档]    @classmethod
    def from_parent(cls, parent: "Node", **kw):
        """Public constructor for Nodes.

        This indirection got introduced in order to enable removing
        the fragile logic from the node constructors.

        Subclasses can use ``super().from_parent(...)`` when overriding the
        construction.

        :param parent: The parent node of this Node.
        """
        if "config" in kw:
            raise TypeError("config is not a valid argument for from_parent")
        if "session" in kw:
            raise TypeError("session is not a valid argument for from_parent")
        return cls._create(parent=parent, **kw)

    @property
    def ihook(self):
        """fspath-sensitive hook proxy used to call pytest hooks."""
        return self.session.gethookproxy(self.fspath)

    def __repr__(self) -> str:
        return "<{} {}>".format(self.__class__.__name__, getattr(self, "name", None))

[文档]    def warn(self, warning: Warning) -> None:
        """Issue a warning for this Node.

        Warnings will be displayed after the test session, unless explicitly suppressed.

        :param Warning warning:
            The warning instance to issue.

        :raises ValueError: If ``warning`` instance is not a subclass of Warning.

        Example usage:

        .. code-block:: python

            node.warn(PytestWarning("some message"))
            node.warn(UserWarning("some message"))

        .. versionchanged:: 6.2
            Any subclass of :class:`Warning` is now accepted, rather than only
            :class:`PytestWarning <pytest.PytestWarning>` subclasses.
        """
        # enforce type checks here to avoid getting a generic type error later otherwise.
        if not isinstance(warning, Warning):
            raise ValueError(
                "warning must be an instance of Warning or subclass, got {!r}".format(
                    warning
                )
            )
        path, lineno = get_fslocation_from_item(self)
        assert lineno is not None
        warnings.warn_explicit(
            warning, category=None, filename=str(path), lineno=lineno + 1,
        )

    # Methods for ordering nodes.

    @property
    def nodeid(self) -> str:
        """A ::-separated string denoting its collection tree address."""
        return self._nodeid

    def __hash__(self) -> int:
        return hash(self._nodeid)

    def setup(self) -> None:
        pass

    def teardown(self) -> None:
        pass

[文档]    def listchain(self) -> List["Node"]:
        """Return list of all parent collectors up to self, starting from
        the root of collection tree."""
        chain = []
        item: Optional[Node] = self
        while item is not None:
            chain.append(item)
            item = item.parent
        chain.reverse()
        return chain

[文档]    def add_marker(
        self, marker: Union[str, MarkDecorator], append: bool = True
    ) -> None:
        """Dynamically add a marker object to the node.

        :param append:
            Whether to append the marker, or prepend it.
        """
        from _pytest.mark import MARK_GEN

        if isinstance(marker, MarkDecorator):
            marker_ = marker
        elif isinstance(marker, str):
            marker_ = getattr(MARK_GEN, marker)
        else:
            raise ValueError("is not a string or pytest.mark.* Marker")
        self.keywords[marker_.name] = marker_
        if append:
            self.own_markers.append(marker_.mark)
        else:
            self.own_markers.insert(0, marker_.mark)

[文档]    def iter_markers(self, name: Optional[str] = None) -> Iterator[Mark]:
        """Iterate over all markers of the node.

        :param name: If given, filter the results by the name attribute.
        """
        return (x[1] for x in self.iter_markers_with_node(name=name))

[文档]    def iter_markers_with_node(
        self, name: Optional[str] = None
    ) -> Iterator[Tuple["Node", Mark]]:
        """Iterate over all markers of the node.

        :param name: If given, filter the results by the name attribute.
        :returns: An iterator of (node, mark) tuples.
        """
        for node in reversed(self.listchain()):
            for mark in node.own_markers:
                if name is None or getattr(mark, "name", None) == name:
                    yield node, mark

    @overload
    def get_closest_marker(self, name: str) -> Optional[Mark]:
        ...

    @overload
    def get_closest_marker(self, name: str, default: Mark) -> Mark:
        ...

[文档]    def get_closest_marker(
        self, name: str, default: Optional[Mark] = None
    ) -> Optional[Mark]:
        """Return the first marker matching the name, from closest (for
        example function) to farther level (for example module level).

        :param default: Fallback return value if no marker was found.
        :param name: Name to filter by.
        """
        return next(self.iter_markers(name=name), default)

[文档]    def listextrakeywords(self) -> Set[str]:
        """Return a set of all extra keywords in self and any parents."""
        extra_keywords: Set[str] = set()
        for item in self.listchain():
            extra_keywords.update(item.extra_keyword_matches)
        return extra_keywords

    def listnames(self) -> List[str]:
        return [x.name for x in self.listchain()]

[文档]    def addfinalizer(self, fin: Callable[[], object]) -> None:
        """Register a function to be called when this node is finalized.

        This method can only be called when this node is active
        in a setup chain, for example during self.setup().
        """
        self.session._setupstate.addfinalizer(fin, self)

[文档]    def getparent(self, cls: Type[_NodeType]) -> Optional[_NodeType]:
        """Get the next parent node (including self) which is an instance of
        the given class."""
        current: Optional[Node] = self
        while current and not isinstance(current, cls):
            current = current.parent
        assert current is None or isinstance(current, cls)
        return current

    def _prunetraceback(self, excinfo: ExceptionInfo[BaseException]) -> None:
        pass

    def _repr_failure_py(
        self,
        excinfo: ExceptionInfo[BaseException],
        style: "Optional[_TracebackStyle]" = None,
    ) -> TerminalRepr:
        from _pytest.fixtures import FixtureLookupError

        if isinstance(excinfo.value, ConftestImportFailure):
            excinfo = ExceptionInfo(excinfo.value.excinfo)
        if isinstance(excinfo.value, fail.Exception):
            if not excinfo.value.pytrace:
                style = "value"
        if isinstance(excinfo.value, FixtureLookupError):
            return excinfo.value.formatrepr()
        if self.config.getoption("fulltrace", False):
            style = "long"
        else:
            tb = _pytest._code.Traceback([excinfo.traceback[-1]])
            self._prunetraceback(excinfo)
            if len(excinfo.traceback) == 0:
                excinfo.traceback = tb
            if style == "auto":
                style = "long"
        # XXX should excinfo.getrepr record all data and toterminal() process it?
        if style is None:
            if self.config.getoption("tbstyle", "auto") == "short":
                style = "short"
            else:
                style = "long"

        if self.config.getoption("verbose", 0) > 1:
            truncate_locals = False
        else:
            truncate_locals = True

        # excinfo.getrepr() formats paths relative to the CWD if `abspath` is False.
        # It is possible for a fixture/test to change the CWD while this code runs, which
        # would then result in the user seeing confusing paths in the failure message.
        # To fix this, if the CWD changed, always display the full absolute path.
        # It will be better to just always display paths relative to invocation_dir, but
        # this requires a lot of plumbing (#6428).
        try:
            abspath = Path(os.getcwd()) != self.config.invocation_params.dir
        except OSError:
            abspath = True

        return excinfo.getrepr(
            funcargs=True,
            abspath=abspath,
            showlocals=self.config.getoption("showlocals", False),
            style=style,
            tbfilter=False,  # pruned already, or in --fulltrace mode.
            truncate_locals=truncate_locals,
        )

[文档]    def repr_failure(
        self,
        excinfo: ExceptionInfo[BaseException],
        style: "Optional[_TracebackStyle]" = None,
    ) -> Union[str, TerminalRepr]:
        """Return a representation of a collection or test failure.

        :param excinfo: Exception information for the failure.
        """
        return self._repr_failure_py(excinfo, style)


def get_fslocation_from_item(
    node: "Node",
) -> Tuple[Union[str, py.path.local], Optional[int]]:
    """Try to extract the actual location from a node, depending on available attributes:

    * "location": a pair (path, lineno)
    * "obj": a Python object that the node wraps.
    * "fspath": just a path

    :rtype: A tuple of (str|py.path.local, int) with filename and line number.
    """
    # See Item.location.
    location: Optional[Tuple[str, Optional[int], str]] = getattr(node, "location", None)
    if location is not None:
        return location[:2]
    obj = getattr(node, "obj", None)
    if obj is not None:
        return getfslineno(obj)
    return getattr(node, "fspath", "unknown location"), -1


[文档]class Collector(Node):
    """Collector instances create children through collect() and thus
    iteratively build a tree."""

[文档]    class CollectError(Exception):
        """An error during collection, contains a custom message."""

[文档]    def collect(self) -> Iterable[Union["Item", "Collector"]]:
        """Return a list of children (items and collectors) for this
        collection node."""
        raise NotImplementedError("abstract")

    # TODO: This omits the style= parameter which breaks Liskov Substitution.
[文档]    def repr_failure(  # type: ignore[override]
        self, excinfo: ExceptionInfo[BaseException]
    ) -> Union[str, TerminalRepr]:
        """Return a representation of a collection failure.

        :param excinfo: Exception information for the failure.
        """
        if isinstance(excinfo.value, self.CollectError) and not self.config.getoption(
            "fulltrace", False
        ):
            exc = excinfo.value
            return str(exc.args[0])

        # Respect explicit tbstyle option, but default to "short"
        # (_repr_failure_py uses "long" with "fulltrace" option always).
        tbstyle = self.config.getoption("tbstyle", "auto")
        if tbstyle == "auto":
            tbstyle = "short"

        return self._repr_failure_py(excinfo, style=tbstyle)

    def _prunetraceback(self, excinfo: ExceptionInfo[BaseException]) -> None:
        if hasattr(self, "fspath"):
            traceback = excinfo.traceback
            ntraceback = traceback.cut(path=self.fspath)
            if ntraceback == traceback:
                ntraceback = ntraceback.cut(excludepath=tracebackcutdir)
            excinfo.traceback = ntraceback.filter()


def _check_initialpaths_for_relpath(session, fspath):
    for initial_path in session._initialpaths:
        if fspath.common(initial_path) == initial_path:
            return fspath.relto(initial_path)


[文档]class FSCollector(Collector):
    def __init__(
        self,
        fspath: py.path.local,
        parent=None,
        config: Optional[Config] = None,
        session: Optional["Session"] = None,
        nodeid: Optional[str] = None,
    ) -> None:
        name = fspath.basename
        if parent is not None:
            rel = fspath.relto(parent.fspath)
            if rel:
                name = rel
            name = name.replace(os.sep, SEP)
        self.fspath = fspath

        session = session or parent.session

        if nodeid is None:
            nodeid = self.fspath.relto(session.config.rootdir)

            if not nodeid:
                nodeid = _check_initialpaths_for_relpath(session, fspath)
            if nodeid and os.sep != SEP:
                nodeid = nodeid.replace(os.sep, SEP)

        super().__init__(name, parent, config, session, nodeid=nodeid, fspath=fspath)

[文档]    @classmethod
    def from_parent(cls, parent, *, fspath, **kw):
        """The public constructor."""
        return super().from_parent(parent=parent, fspath=fspath, **kw)

    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)


[文档]class File(FSCollector):
    """Base class for collecting tests from a file.

    :ref:`non-python tests`.
    """


[文档]class Item(Node):
    """A basic test invocation item.

    Note that for a single function there might be multiple test invocation items.
    """

    nextitem = None

    def __init__(
        self,
        name,
        parent=None,
        config: Optional[Config] = None,
        session: Optional["Session"] = None,
        nodeid: Optional[str] = None,
    ) -> None:
        super().__init__(name, parent, config, session, nodeid=nodeid)
        self._report_sections: List[Tuple[str, str, str]] = []

        #: A list of tuples (name, value) that holds user defined properties
        #: for this test.
        self.user_properties: List[Tuple[str, object]] = []

    def runtest(self) -> None:
        raise NotImplementedError("runtest must be implemented by Item subclass")

[文档]    def add_report_section(self, when: str, key: str, content: str) -> None:
        """Add a new report section, similar to what's done internally to add
        stdout and stderr captured output::

            item.add_report_section("call", "stdout", "report section contents")

        :param str when:
            One of the possible capture states, ``"setup"``, ``"call"``, ``"teardown"``.
        :param str key:
            Name of the section, can be customized at will. Pytest uses ``"stdout"`` and
            ``"stderr"`` internally.
        :param str content:
            The full contents as a string.
        """
        if content:
            self._report_sections.append((when, key, content))

    def reportinfo(self) -> Tuple[Union[py.path.local, str], Optional[int], str]:
        return self.fspath, None, ""

    @cached_property
    def location(self) -> Tuple[str, Optional[int], str]:
        location = self.reportinfo()
        fspath = absolutepath(str(location[0]))
        relfspath = self.session._node_location_to_relpath(fspath)
        assert type(location[2]) is str
        return (relfspath, location[1], location[2])