"""Column-contract guard for `Slot` (dcy-001 OQ-2 / REQ-003 FR-5).

Asserts the `Slot` dataclass field set matches the declared `EXPECTED_SLOT_FIELDS`
so any field add/remove fails loudly. Names/presence only — type mapping lives in
dcy-001 부록 A / docs/data-model.md, not here.

DB-side (information_schema) drift checking is out of scope for this iteration and
is deferred to the persistence REQ (dcy-001 OQ-2).
"""
from __future__ import annotations

import dataclasses

from trex_core.domain.slot import EXPECTED_SLOT_FIELDS, Slot


def test_slot_fields_match_expected_contract():
    """AC-2: dataclass field set == declared contract."""
    actual = {f.name for f in dataclasses.fields(Slot)}
    assert actual == set(EXPECTED_SLOT_FIELDS)


def test_contract_detects_added_field():
    """AC-3 negative case: an extra field on a Slot-like dataclass must be caught.

    Recreates the guard against a mutated copy so the test proves the assertion
    fails when fields drift, without mutating the real Slot.
    """
    mutated_fields = {f.name for f in dataclasses.fields(Slot)} | {"unexpected_new_field"}
    assert mutated_fields != set(EXPECTED_SLOT_FIELDS)


def test_contract_detects_removed_field():
    """AC-3 negative case: a removed field must be caught."""
    reduced_fields = {f.name for f in dataclasses.fields(Slot)} - {"forced_close_at"}
    assert reduced_fields != set(EXPECTED_SLOT_FIELDS)