from copy import copy

import sqlalchemy as sa
from pytest import raises
from sqlalchemy.ext.declarative import declarative_base

from sqlalchemy_utils import get_column_key


class TestGetColumnKey(object):
    def setup_method(self, method):
        Base = declarative_base()

        class Building(Base):
            __tablename__ = 'building'
            id = sa.Column(sa.Integer, primary_key=True)
            name = sa.Column('_name', sa.Unicode(255))

        class Movie(Base):
            __tablename__ = 'movie'
            id = sa.Column(sa.Integer, primary_key=True)

        self.Building = Building
        self.Movie = Movie

    def test_supports_aliases(self):
        assert (
            get_column_key(self.Building, self.Building.__table__.c.id)
            ==
            'id'
        )
        assert (
            get_column_key(self.Building, self.Building.__table__.c._name)
            ==
            'name'
        )

    def test_supports_vague_matching_of_column_objects(self):
        column = copy(self.Building.__table__.c._name)
        assert get_column_key(self.Building, column) == 'name'

    def test_throws_value_error_for_unknown_column(self):
        with raises(sa.orm.exc.UnmappedColumnError):
            get_column_key(self.Building, self.Movie.__table__.c.id)