backend/tests/test_persistence.py

"""Persistence and security contract tests."""
import json
import os
import tempfile

import pytest

BACKEND_DIR = os.path.dirname(os.path.dirname(os.path.abspath(__file__)))
if BACKEND_DIR not in __import__("sys").path:
    __import__("sys").path.insert(0, BACKEND_DIR)

import persistence as persist  # noqa: E402


def test_atomic_save_roundtrip():
    with tempfile.TemporaryDirectory() as tmp:
        path = os.path.join(tmp, "data.json")
        payload = {"items": [1, 2, 3], "name": "test"}
        persist.save_json(path, payload)
        loaded = persist.load_json(path, {})
        assert loaded == payload


def test_load_missing_returns_default():
    with tempfile.TemporaryDirectory() as tmp:
        path = os.path.join(tmp, "missing.json")
        assert persist.load_json(path, []) == []


def test_concurrent_writes_do_not_corrupt():
    with tempfile.TemporaryDirectory() as tmp:
        path = os.path.join(tmp, "list.json")
        for i in range(20):
            data = persist.load_json(path, [])
            data.append(i)
            persist.save_json(path, data)
        loaded = persist.load_json(path, [])
        assert len(loaded) == 20
        assert loaded[0] == 0
        assert loaded[-1] == 19