def test_double(self):

        users, orders, User, Address, Order, addresses = (self.tables.users,
                                self.tables.orders,
                                self.classes.User,
                                self.classes.Address,
                                self.classes.Order,
                                self.tables.addresses)


        openorders = sa.alias(orders, 'openorders')
        closedorders = sa.alias(orders, 'closedorders')

        mapper(Address, addresses)
        mapper(Order, orders)

        open_mapper = mapper(Order, openorders, non_primary=True)
        closed_mapper = mapper(Order, closedorders, non_primary=True)

        mapper(User, users, properties = dict(
            addresses = relationship(Address, lazy='subquery',
                                        order_by=addresses.c.id),
            open_orders = relationship(
                open_mapper,
                primaryjoin=sa.and_(openorders.c.isopen == 1,
                                 users.c.id==openorders.c.user_id),
                lazy='subquery', order_by=openorders.c.id),
            closed_orders = relationship(
                closed_mapper,
                primaryjoin=sa.and_(closedorders.c.isopen == 0,
                                 users.c.id==closedorders.c.user_id),
                lazy='subquery', order_by=closedorders.c.id)))

        q = create_session().query(User).order_by(User.id)

        def go():
            eq_([
                User(
                    id=7,
                    addresses=[Address(id=1)],
                    open_orders = [Order(id=3)],
                    closed_orders = [Order(id=1), Order(id=5)]
                ),
                User(
                    id=8,
                    addresses=[Address(id=2), Address(id=3), Address(id=4)],
                    open_orders = [],
                    closed_orders = []
                ),
                User(
                    id=9,
                    addresses=[Address(id=5)],
                    open_orders = [Order(id=4)],
                    closed_orders = [Order(id=2)]
                ),
                User(id=10)

            ], q.all())
        self.assert_sql_count(testing.db, go, 4)
By default, tests should not force garbage collection.
dataset/ETHPy150Open zzzeek/sqlalchemy/test/orm/test_subquery_relations.py/EagerTest.test_double--crossover with--dataset/ETHPy150Open kuri65536/python-for-android/python-modules/twisted/twisted/trial/test/test_tests.py/TestGarbageCollectionDefault.test_collectNotDefault