"""验证 0018 迁移使用 server_default='zh' 落库（防止已有用户 NULL）。"""

from __future__ import annotations

from pathlib import Path

from app.features.user.models import User


def test_migration_0018_uses_server_default_zh() -> None:
    path = (
        Path(__file__).resolve().parent.parent
        / "alembic"
        / "versions"
        / "0018_users_language_preference.py"
    )
    src = path.read_text(encoding="utf-8")
    assert "language_preference" in src
    # server_default 'zh' 是已有用户回填的关键
    assert "server_default=sa.text(\"'zh'\")" in src
    assert "nullable=False" in src
    # 在多行 op.add_column 调用中第一参数为 "users"
    assert "op.add_column" in src
    assert '"users"' in src


def test_user_model_language_preference_default_zh() -> None:
    """模型层默认值与迁移一致；新建实例不传值时为 'zh'。"""
    column = User.__table__.c.language_preference
    assert column.default is not None
    assert column.default.arg == "zh"
    assert column.server_default is not None
    assert "zh" in str(column.server_default.arg)
    assert column.nullable is False