test_set_level_safety.py

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#!/usr/bin/env python3
# -*- coding: utf-8 -*-
# tests/tests_diag/test_set_level_safety.py
 
"""
Purpose
-------
OI-528 regression coverage — :func:`oct.diag.oct_diag.set_level` and the
paired :func:`restore_config` helper must provide safe in-place edits of
``debug_config.json``. A bad level write can brick diagnostics, so the
operation is backed by a ``<path>.bk`` sidecar and a ``--dry-run`` flag
that short-circuits both writes.
 
Responsibilities
----------------
- ``--dry-run`` never writes to the config or creates ``.bk``.
- A real write creates ``<path>.bk`` containing the original text.
- :func:`restore_config` round-trips the backup back onto the config.
- Calling :func:`restore_config` with no backup raises cleanly.
- Re-running ``set_level`` overwrites ``.bk`` with the pre-edit text.
 
Diagnostics
-----------
Domain: DIAG-TESTS
Levels:
    L2 — test lifecycle
    L3 — assertion details
    L4 — deep tracing
 
Contracts
---------
- All config writes and backups use ``tmp_path``; no real
  ``debug_config.json`` is modified.
"""
 
from __future__ import annotations
 
import json
from pathlib import Path
 
import pytest
from click.testing import CliRunner
 
from oct.cli import cli
from oct.diag.oct_diag import restore_config, set_level
 
 
_V2_CONFIG = {
    "_schema_version": "2.0",
    "DEBUG_LEVELS": {
        "GENERAL": {"level": 1, "color": "default"},
        "NET": {"level": 2, "color": "blue"},
    },
    "global_settings": {"mode": "dev"},
}
 
 
def _write_config(root: Path, data: dict) -> Path:
    diag = root / "oc_diagnostics"
    diag.mkdir()
    # find_project_root requires docs/ + tests/ siblings alongside
    # oc_diagnostics/ to recognise the directory as an OC project.
    (root / "docs").mkdir()
    (root / "tests").mkdir()
    cfg = diag / "debug_config.json"
    cfg.write_text(json.dumps(data, indent=2) + "\n", encoding="utf-8")
    return cfg
 
 
def test_dry_run_does_not_write_or_backup(tmp_path):
    cfg = _write_config(tmp_path, _V2_CONFIG)
    original_text = cfg.read_text(encoding="utf-8")
 
    result = set_level(tmp_path, "GENERAL", 4, dry_run=True)
 
    assert cfg.read_text(encoding="utf-8") == original_text
    assert not cfg.with_suffix(".json.bk").exists()
    assert result["DEBUG_LEVELS"]["GENERAL"]["level"] == 4
 
 
def test_write_creates_backup_with_original_text(tmp_path):
    cfg = _write_config(tmp_path, _V2_CONFIG)
    original_text = cfg.read_text(encoding="utf-8")
 
    set_level(tmp_path, "GENERAL", 3)
 
    bk = cfg.with_suffix(".json.bk")
    assert bk.is_file()
    assert bk.read_text(encoding="utf-8") == original_text
    reloaded = json.loads(cfg.read_text(encoding="utf-8"))
    assert reloaded["DEBUG_LEVELS"]["GENERAL"]["level"] == 3
 
 
def test_restore_config_round_trips_backup(tmp_path):
    cfg = _write_config(tmp_path, _V2_CONFIG)
    original_text = cfg.read_text(encoding="utf-8")
    set_level(tmp_path, "GENERAL", 4)
    assert json.loads(cfg.read_text(encoding="utf-8"))["DEBUG_LEVELS"]["GENERAL"]["level"] == 4
 
    restored = restore_config(tmp_path)
 
    assert restored == cfg
    assert cfg.read_text(encoding="utf-8") == original_text
 
 
def test_restore_config_without_backup_raises(tmp_path):
    _write_config(tmp_path, _V2_CONFIG)
 
    with pytest.raises(FileNotFoundError):
        restore_config(tmp_path)
 
 
def test_backup_is_overwritten_with_pre_edit_text_on_second_write(tmp_path):
    cfg = _write_config(tmp_path, _V2_CONFIG)
    set_level(tmp_path, "GENERAL", 3)   # first edit: .bk holds original
    set_level(tmp_path, "NET", 0)       # second edit: .bk holds post-first-edit
 
    bk = cfg.with_suffix(".json.bk")
    backup_state = json.loads(bk.read_text(encoding="utf-8"))
    assert backup_state["DEBUG_LEVELS"]["GENERAL"]["level"] == 3
    assert backup_state["DEBUG_LEVELS"]["NET"]["level"] == 2
 
 
def test_cli_set_level_dry_run_does_not_touch_files(tmp_path, monkeypatch):
    cfg = _write_config(tmp_path, _V2_CONFIG)
    original_text = cfg.read_text(encoding="utf-8")
    monkeypatch.chdir(tmp_path)
 
    runner = CliRunner()
    result = runner.invoke(cli, ["diag", "set-level", "GENERAL", "4", "--dry-run"])
 
    assert result.exit_code == 0, result.output
    assert "[DRY RUN]" in result.output
    assert cfg.read_text(encoding="utf-8") == original_text
    assert not cfg.with_suffix(".json.bk").exists()
 
 
def test_cli_restore_command_round_trips(tmp_path, monkeypatch):
    cfg = _write_config(tmp_path, _V2_CONFIG)
    original_text = cfg.read_text(encoding="utf-8")
    monkeypatch.chdir(tmp_path)
 
    runner = CliRunner()
    runner.invoke(cli, ["diag", "set-level", "GENERAL", "4"])
    result = runner.invoke(cli, ["diag", "restore"])
 
    assert result.exit_code == 0, result.output
    assert cfg.read_text(encoding="utf-8") == original_text