Method test_add_property_in_mapper_event

test/orm/test_mapper.py:1047–1156

test #12858, ability to add properties of all types within event hooks where the mapper is not necessarily set up with property collections.

(
        self, property_type, connection, metadata, event_name
    )

        ],
    )
    def test_add_property_in_mapper_event(
        self, property_type, connection, metadata, event_name
    ):
        """test #12858, ability to add properties of all types within
        event hooks where the mapper is not necessarily set up with property
        collections.

        """

        Address = self.classes.Address

        users = Table(
            "deferred_users",
            metadata,
            Column("id", Integer, primary_key=True),
            Column("name", String(50)),
        )

        # use an ad-hoc User class.   Assigning an event holder to a
        # class right now means that class permanently has that mapper
        # event associated with it, whenever a new mapper is created.
        # if you call event.remove(User), it removes the event from the mapper,
        # but not the "event hold" that associates it again on a new mapper.
        # this is probably a bug but not the one we came here today to fix
        class User:
            pass

        def setup_props(mapper, class_):
            if property_type.ColumnProperty:
                col = Column("new_column", String(50))
                mapper.local_table.append_column(col)
                mapper.add_property(
                    col.key, deferred(col, group="deferred_group")
                )
            elif property_type.Column:
                col = Column("new_column", String(50))
                mapper.local_table.append_column(col)
                mapper.add_property(col.key, col)
            elif property_type.Relationship:
                mapper.add_property("addresses", relationship(Address))
            else:
                property_type.fail()

        event.listen(User, event_name.name, setup_props)

        if property_type.ColumnProperty:
            self.mapper(
                User,
                users,
                properties={
                    "name": deferred(users.c.name, group="deferred_group")
                },
            )
        else:
            self.mapper(User, users)

        if property_type.Relationship:
            addresses_table = Table(