Class FuncFixtureInfo

src/_pytest/fixtures.py:390–437

Fixture-related information for a fixture-requesting item (e.g. test function). This is used to examine the fixtures which an item requests statically (known during collection). This includes autouse fixtures, fixtures requested by the `usefixtures` marker, fixtures requested in the

@dataclasses.dataclass(frozen=True)
class FuncFixtureInfo:
    """Fixture-related information for a fixture-requesting item (e.g. test
    function).

    This is used to examine the fixtures which an item requests statically
    (known during collection). This includes autouse fixtures, fixtures
    requested by the `usefixtures` marker, fixtures requested in the function
    parameters, and the transitive closure of these.

    An item may also request fixtures dynamically (using `request.getfixturevalue`);
    these are not reflected here.
    """

    __slots__ = ("argnames", "initialnames", "name2fixturedefs", "names_closure")

    # Fixture names that the item requests directly by function parameters.
    argnames: tuple[str, ...]
    # Fixture names that the item immediately requires. These include
    # argnames + fixture names specified via usefixtures and via autouse=True in
    # fixture definitions.
    initialnames: tuple[str, ...]
    # The transitive closure of the fixture names that the item requires.
    # Note: can't include dynamic dependencies (`request.getfixturevalue` calls).
    names_closure: list[str]
    # A map from a fixture name in the transitive closure to the FixtureDefs
    # matching the name which are applicable to this function.
    # There may be multiple overriding fixtures with the same name. The
    # sequence is ordered from furthest to closes to the function.
    name2fixturedefs: dict[str, Sequence[FixtureDef[Any]]]

    def prune_dependency_tree(self) -> None:
        """Recompute names_closure from initialnames and name2fixturedefs.

        Can only reduce names_closure, which means that the new closure will
        always be a subset of the old one. The order is preserved.

        This method is needed because direct parametrization may shadow some
        of the fixtures that were included in the originally built dependency
        tree. In this way the dependency tree can get pruned, and the closure
        of argnames may get reduced.
        """
        closure = set(
            traverse_fixture_closure(
                self.initialnames,
                getfixturedefs=self.name2fixturedefs.get,
            )
        )
        self.names_closure[:] = (name for name in self.names_closure if name in closure)


class FixtureRequest(abc.ABC):