from typing import Optional

import pytest
from sqlmodel import Field, SQLModel, create_engine


def test_missing_sql_type():
    class CustomType:
        @classmethod
        def __get_validators__(cls):
            yield cls.validate

        @classmethod
        def validate(cls, v):
            return v
            
    with pytest.raises(ValueError):
        class Item(SQLModel, table=True):
            id: Optional[int] = 