import pytest
import factory
from sqlalchemy import create_engine, Column, String, BigInteger
from sqlalchemy.ext.declarative import declarative_base
from sqlalchemy.orm import sessionmaker

engine = create_engine('DB_CONNECTION_URL')

Base = declarative_base(bind=engine)
Session = sessionmaker()

class UserModel(Base):
    __tablename__ = 'account'

    id = Column(BigInteger, primary_key=True)
    name = Column(String, nullable=False)
    email = Column(String, nullable=False)

class UserFactory(factory.alchemy.SQLAlchemyModelFactory):
    id = factory.Sequence(lambda n: '%s' % n)
    name = factory.Faker('name')
    email = factory.Faker('email')

    class Meta:
        model = UserModel

@pytest.fixture(scope='module')
def connection():
    connection = engine.connect()
    yield connection
    connection.close()

@pytest.fixture(scope='function')
def session(connection):
    transaction = connection.begin()
    session = Session(bind=connection)
    UserFactory._meta.sqlalchemy_session = session
    yield session
    session.close()
    transaction.rollback()

def my_func_to_delete_user(session, user_id):
    session.query(UserModel).filter(UserModel.id == user_id).delete()

def test_case(session):
    user = UserFactory.create()
    assert session.query(UserModel).one()

    my_func_to_delete_user(session, user.id)

    result = session.query(UserModel).one_or_none()
    assert result is None