import pytest
from pydantic import ValidationError

from flyway.config import Settings


def test_database_url_has_no_built_in_default(monkeypatch):
    """连接串只来自环境变量 / .env（文档 12.6 第 7 条）；缺失时启动失败，而不是悄悄连到某个默认库。"""
    monkeypatch.delenv("FLYWAY_DATABASE_URL", raising=False)
    with pytest.raises(ValidationError):
        Settings(_env_file=None)