from sqlalchemy import Column
from sqlalchemy import Integer
from sqlalchemy import MetaData
from sqlalchemy import select
from sqlalchemy import String
from sqlalchemy import Table
from sqlalchemy.sql import util as sql_util
from sqlalchemy.sql.elements import ColumnElement
from sqlalchemy.testing import eq_
from sqlalchemy.testing import fixtures


class MiscTest(fixtures.TestBase):
    def test_column_element_no_visit(self):
        class MyElement(ColumnElement):
            _traverse_internals = []

        eq_(sql_util.find_tables(MyElement(), check_columns=True), [])

    def test_find_tables_selectable(self):
        metadata = MetaData()
        common = Table(
            "common",
            metadata,
            Column("id", Integer, primary_key=True),
            Column("data", Integer),
            Column("extra", String(45)),
        )

        subset_select = select([common.c.id, common.c.data]).alias()

        eq_(sql_util.find_tables(subset_select), [common])