Class FixtureManager

src/_pytest/fixtures.py:1683–2169

pytest fixture definitions and information is stored and managed from this class. During collection fm.parsefactories() is called multiple times to parse fixture function definitions into FixtureDef objects and internal data structures. During collection of test functions, meta

class FixtureManager:
    """pytest fixture definitions and information is stored and managed
    from this class.

    During collection fm.parsefactories() is called multiple times to parse
    fixture function definitions into FixtureDef objects and internal
    data structures.

    During collection of test functions, metafunc-mechanics instantiate
    a FuncFixtureInfo object which is cached per node/func-name.
    This FuncFixtureInfo object is later retrieved by Function nodes
    which themselves offer a fixturenames attribute.

    The FuncFixtureInfo object holds information about fixtures and FixtureDefs
    relevant for a particular function. An initial list of fixtures is
    assembled like this:

    - config-defined usefixtures
    - autouse-marked fixtures along the collection chain up from the function
    - usefixtures markers at module/class/function level
    - test function funcargs

    Subsequently the funcfixtureinfo.fixturenames attribute is computed
    as the closure of the fixtures needed to setup the initial fixtures,
    i.e. fixtures needed by fixture functions themselves are appended
    to the fixturenames list.

    Upon the test-setup phases all fixturenames are instantiated, retrieved
    by a lookup of their FuncFixtureInfo.
    """

    def __init__(self, session: Session) -> None:
        self.session = session
        self.config: Config = session.config
        # Maps a fixture name (argname) to all of the FixtureDefs in the test
        # suite/plugins defined with this name. Populated by parsefactories().
        # TODO: The order of the FixtureDefs list of each arg is significant,
        #       explain.
        self._arg2fixturedefs: Final[dict[str, list[FixtureDef[Any]]]] = {}
        # A mapping from a node to a list of autouse fixture names it defines.
        # The Session entry holds global usefixtures from config.
        self._node_autousenames: Final[dict[nodes.Node, list[str]]] = {
            session: list(self.config.getini("usefixtures")),
        }
        # Legacy fallback: nodeid string -> autouse names, for plugins still
        # using the deprecated nodeid-based API without a node reference.
        self._nodeid_autousenames: Final[dict[str, list[str]]] = {}
        # Pending conftest modules waiting to be parsed when their Directory is collected.
        # Maps directory path -> conftest plugin module.
        self._pending_conftests: Final[dict[Path, object]] = {}
        session.config.pluginmanager.register(self, "funcmanage")
        # Flush initial conftests from directories above rootpath immediately.
        # These will never get a Directory collector, so they need Session scope.
        # This must happen here (not in pytest_make_collect_report) because
        # collection may fail before Session collection starts (e.g. bad args).
        self._flush_pending_conftests_to_session(session)

    def getfixtureinfo(