Method test_dc_decl_usage

test/ext/test_associationproxy.py:3968–4064

test use of assoc prox as the default descriptor for a dataclasses.field. This exercises #8880

(self, dc_decl_base, embed_in_field, field_kw)

        argnames="field_kw",
    )
    def test_dc_decl_usage(self, dc_decl_base, embed_in_field, field_kw):
        """test use of assoc prox as the default descriptor for a
        dataclasses.field.

        This exercises #8880

        """

        if field_kw.pop("default_factory", False) and not embed_in_field:
            has_default_factory = True
            field_kw["default_factory"] = lambda: [
                Keyword("l1"),
                Keyword("l2"),
                Keyword("l3"),
            ]
        else:
            has_default_factory = False

        class User(dc_decl_base):
            __allow_unmapped__ = True

            __tablename__ = "user"

            id: Mapped[int] = mapped_column(
                primary_key=True, repr=True, init=False
            )

            user_keyword_associations: Mapped[List[UserKeywordAssociation]] = (
                relationship(
                    back_populates="user",
                    cascade="all, delete-orphan",
                    init=False,
                )
            )

            if embed_in_field:
                # this is an incorrect form to use with
                # MappedAsDataclass.  However, we want to make sure it
                # works as kind of a test to ensure we are being as well
                # behaved as possible with an explicit dataclasses.field(),
                # by testing that it uses its normal descriptor-as-default
                # behavior
                keywords: AssociationProxy[list[str]] = dataclasses.field(
                    default=association_proxy(
                        "user_keyword_associations", "keyword"
                    ),
                    **field_kw,
                )
            else:
                keywords: AssociationProxy[list[str]] = association_proxy(
                    "user_keyword_associations", "keyword", **field_kw
                )

        UserKeywordAssociation, Keyword = self._dc_keyword_mapping(
            User, dc_decl_base
        )

        # simplify __qualname__ so we can test repr() more easily