'use strict';

/**
 * Behavioral tests for codex-agent-toml.cjs (#3243, ADR-2313 Phase 3).
 *
 * Module: msd-core/bin/lib/codex-agent-toml.cjs
 * Exports: PARSE_REASON, parseCodexAgentToml, renderCodexAgentToml,
 *          stripModel, stripReasoningEffort
 *
 * Spec: .msd/phase/feat-3243-codex-toml-sync/{40-design,50-test-matrix}.md
 * Row numbers below (# A<N>) map 1:1 to 50-test-matrix.md's "A — the IR" table.
 *
 * Every fixture is hand-authored against the real `generateCodexAgentToml`
 * shape (header fields + `developer_instructions = '''...'''`), never produced
 * by calling that emitter (CONTRIBUTING's fixture-provenance rule, #2371) — a
 * fixture generated by the writer under test could only confirm what the
 * writer already believes about its own output.
 */

const { test, describe } = require('node:test');
const assert = require('node:assert/strict');

const {
  PARSE_REASON,
  parseCodexAgentToml,
  renderCodexAgentToml,
  stripModel,
  stripReasoningEffort,
} = require('../msd-core/bin/lib/codex-agent-toml.cjs');

// Row 18a's CRLF fixture (and A12 here) is derived at test runtime, never read
// from a committed file: `.gitattributes` (`* text=auto eol=lf`, repo-wide) would
// normalize any committed `\r\n` fixture back to LF on checkout, silently
// defeating the CRLF assertion. Authoring LF content and converting it here
// keeps the CRLF-ness under the test's control instead of git's.
function toCrlf(lfContent) {
  return lfContent.replace(/\n/g, '\r\n');
}

// ─── A1-A13 fixtures (hand-authored, #2371) ───────────────────────────────────

const A1_FULL = 'name = "msd-planner"\n' +
  'description = "Plans phases for MSD milestones"\n' +
  'model = "gpt-5.6-sol"\n' +
  'model_reasoning_effort = "high"\n' +
  "developer_instructions = '''\n" +
  'Plan the next phase.\n' +
  "'''\n";

const A2_NO_HEADER_FIELDS = 'name = "msd-plain"\n' +
  'description = "No model, no effort"\n' +
  "developer_instructions = '''\n" +
  'Just work.\n' +
  "'''\n";

const A3_DOUBLE_QUOTED_KEY = 'name = "msd-quoted-double"\n' +
  '"model" = "sonnet"\n' +
  "developer_instructions = '''\n" +
  'Work.\n' +
  "'''\n";

const A3_SINGLE_QUOTED_KEY = "name = \"msd-quoted-single\"\n" +
  "'model' = \"sonnet\"\n" +
  "developer_instructions = '''\n" +
  'Work.\n' +
  "'''\n";

const A4_VERBOSITY_ONLY = 'name = "msd-light"\n' +
  'model_verbosity = "low"\n' +
  "developer_instructions = '''\n" +
  'Work fast.\n' +
  "'''\n";

const A5_MODEL_INSIDE_BLOCK = 'name = "msd-planner"\n' +
  "developer_instructions = '''\n" +
  'When picking a plan, remember: model = "sonnet" is just prose here.\n' +
  "'''\n";

const A6_MODEL_AFTER_BLOCK = 'name = "msd-reordered"\n' +
  "developer_instructions = '''\n" +
  'Work.\n' +
  "'''\n" +
  'model = "sonnet"\n';

const A7_DECOY_MARKER_IN_DESCRIPTION = 'name = "msd-decoy-marker"\n' +
  'description = "mentions developer_instructions = \'\'\' as an example string"\n' +
  'model = "sonnet"\n' +
  "developer_instructions = '''\n" +
  'Work.\n' +
  "'''\n";

const A8_SAME_LINE_BLOCK = 'name = "msd-terse"\n' +
  "developer_instructions = '''one line block'''\n";

const A9_UNTERMINATED = 'name = "msd-broken"\n' +
  "developer_instructions = '''\n" +
  'This block never closes.\n';

const A10_NO_BLOCK_AT_ALL = 'name = "msd-noblock"\n' +
  'description = "no prompt block on this agent"\n' +
  '"model" = "sonnet"\n';

const A11_COMMENTED_PIN = 'name = "msd-reviewer"\n' +
  '# model = "sonnet"\n' +
  "developer_instructions = '''\n" +
  'Review.\n' +
  "'''\n";

const A12_CRLF_SOURCE = toCrlf(
  'name = "msd-scribe"\n' +
  'model = "sonnet"\n' +
  "developer_instructions = '''\n" +
  'Write a changelog entry.\n' +
  "'''\n",
);

const A13_BOM_SOURCE = String.fromCharCode(0xfeff) +
  'name = "msd-archivist"\n' +
  'model = "sonnet"\n' +
  "developer_instructions = '''\n" +
  'Archive.\n' +
  "'''\n";

// ─── A1-A13: parse behavior ────────────────────────────────────────────────

describe('parseCodexAgentToml: happy / boundary / hostile', () => {
  test('A1: real emitted .toml (all header fields + block) — every field recovered', () => {
    const result = parseCodexAgentToml(A1_FULL);
    assert.equal(result.ok, true);
    assert.equal(result.doc.model, 'gpt-5.6-sol');
    assert.equal(result.doc.reasoningEffort, 'high');
    assert.equal(result.doc.hadBOM, false);
    assert.equal(result.doc.eol, '\n');
    assert.equal(result.doc.trailingNewline, true);
    assert.notEqual(result.doc.blockRange.start, -1);
  });

  test('A2: header with no model / no effort — both null', () => {
    const result = parseCodexAgentToml(A2_NO_HEADER_FIELDS);
    assert.equal(result.ok, true);
    assert.equal(result.doc.model, null);
    assert.equal(result.doc.reasoningEffort, null);
  });

  test('A3: quoted keys ("model" = / \'model\' =) recovered as key model', () => {
    const doubleQuoted = parseCodexAgentToml(A3_DOUBLE_QUOTED_KEY);
    assert.equal(doubleQuoted.ok, true);
    assert.equal(doubleQuoted.doc.model, 'sonnet');

    const singleQuoted = parseCodexAgentToml(A3_SINGLE_QUOTED_KEY);
    assert.equal(singleQuoted.ok, true);
    assert.equal(singleQuoted.doc.model, 'sonnet');
  });

  test('A4: model_verbosity present, model absent — model: null (full-key anchoring)', () => {
    const result = parseCodexAgentToml(A4_VERBOSITY_ONLY);
    assert.equal(result.ok, true);
    assert.equal(result.doc.model, null);
  });

  test('A5 (hostile, data-loss case): model = inside the block — model: null', () => {
    const result = parseCodexAgentToml(A5_MODEL_INSIDE_BLOCK);
    assert.equal(result.ok, true);
    assert.equal(result.doc.model, null);
  });

  test('A6: model line after the block (hand-reordered) — recovered', () => {
    const result = parseCodexAgentToml(A6_MODEL_AFTER_BLOCK);
    assert.equal(result.ok, true);
    assert.equal(result.doc.model, 'sonnet');
  });

  test('A7 (hostile): description value quoting the block marker does not hide the real model pin', () => {
    const result = parseCodexAgentToml(A7_DECOY_MARKER_IN_DESCRIPTION);
    assert.equal(result.ok, true);
    assert.equal(result.doc.model, 'sonnet');
  });

  test('A8: same-line block — block range is one line', () => {
    const result = parseCodexAgentToml(A8_SAME_LINE_BLOCK);
    assert.equal(result.ok, true);
    assert.equal(result.doc.blockRange.start, result.doc.blockRange.end);
    assert.notEqual(result.doc.blockRange.start, -1);
  });

  test('A9: unterminated block — {ok:false, reason:UNTERMINATED_BLOCK}', () => {
    const result = parseCodexAgentToml(A9_UNTERMINATED);
    assert.equal(result.ok, false);
    assert.equal(result.reason, PARSE_REASON.UNTERMINATED_BLOCK);
  });

  test('A10: no developer_instructions at all — {ok:true}, whole file scanned', () => {
    const result = parseCodexAgentToml(A10_NO_BLOCK_AT_ALL);
    assert.equal(result.ok, true);
    assert.equal(result.doc.blockRange.start, -1);
    assert.equal(result.doc.model, 'sonnet');
  });

  test('A11 (hostile): commented # model = "x" — model: null', () => {
    const result = parseCodexAgentToml(A11_COMMENTED_PIN);
    assert.equal(result.ok, true);
    assert.equal(result.doc.model, null);
  });

  test('A12 (cross-platform): CRLF input parses identically; eol recorded as \\r\\n', () => {
    const result = parseCodexAgentToml(A12_CRLF_SOURCE);
    assert.equal(result.ok, true);
    assert.equal(result.doc.model, 'sonnet');
    assert.equal(result.doc.eol, '\r\n');
  });

  test('A13 (cross-platform): BOM input parses; BOM recorded', () => {
    const result = parseCodexAgentToml(A13_BOM_SOURCE);
    assert.equal(result.ok, true);
    assert.equal(result.doc.model, 'sonnet');
    assert.equal(result.doc.hadBOM, true);
  });
});

// ─── A14 (LOAD-BEARING): round-trip byte-identity ─────────────────────────────
//
// Asserts on raw BYTES, never a re-parsed structure — a renderer that dropped
// every comment or normalized whitespace would still pass a structural
// comparison. A parse/render pair that fails this row silently reformats a
// user's file on every sync.

describe('A14 (load-bearing): render(parse(x)) === x, byte-identical', () => {
  const roundTripFixtures = [
    ['A1_FULL', A1_FULL],
    ['A2_NO_HEADER_FIELDS', A2_NO_HEADER_FIELDS],
    ['A3_DOUBLE_QUOTED_KEY', A3_DOUBLE_QUOTED_KEY],
    ['A3_SINGLE_QUOTED_KEY', A3_SINGLE_QUOTED_KEY],
    ['A4_VERBOSITY_ONLY', A4_VERBOSITY_ONLY],
    ['A5_MODEL_INSIDE_BLOCK', A5_MODEL_INSIDE_BLOCK],
    ['A6_MODEL_AFTER_BLOCK', A6_MODEL_AFTER_BLOCK],
    ['A7_DECOY_MARKER_IN_DESCRIPTION', A7_DECOY_MARKER_IN_DESCRIPTION],
    ['A8_SAME_LINE_BLOCK', A8_SAME_LINE_BLOCK],
    ['A10_NO_BLOCK_AT_ALL', A10_NO_BLOCK_AT_ALL],
    ['A11_COMMENTED_PIN', A11_COMMENTED_PIN],
    ['A12_CRLF_SOURCE', A12_CRLF_SOURCE],
    ['A13_BOM_SOURCE', A13_BOM_SOURCE],
  ];

  for (const [label, source] of roundTripFixtures) {
    test(`round-trips ${label} byte-identically, unmodified`, () => {
      const result = parseCodexAgentToml(source);
      assert.equal(result.ok, true, `${label} must parse ok`);
      const rendered = renderCodexAgentToml(result.doc);
      assert.equal(rendered, source, `${label} must round-trip byte-identically`);
    });
  }
});

// ─── A15/A16: round-trip after a targeted strip ───────────────────────────────

describe('A15/A16: round-trip after stripModel / stripReasoningEffort', () => {
  test('A15: after stripModel(), only the model line is gone — every other byte identical', () => {
    const result = parseCodexAgentToml(A1_FULL);
    assert.equal(result.ok, true);
    const stripped = stripModel(result.doc);
    const rendered = renderCodexAgentToml(stripped);
    const expected = 'name = "msd-planner"\n' +
      'description = "Plans phases for MSD milestones"\n' +
      'model_reasoning_effort = "high"\n' +
      "developer_instructions = '''\n" +
      'Plan the next phase.\n' +
      "'''\n";
    assert.equal(rendered, expected);
    assert.equal(stripped.model, null);
    assert.equal(stripped.reasoningEffort, 'high', 'the effort line must survive untouched');
  });

  test('A16: after stripReasoningEffort(), only that line is gone — every other byte identical', () => {
    const result = parseCodexAgentToml(A1_FULL);
    assert.equal(result.ok, true);
    const stripped = stripReasoningEffort(result.doc);
    const rendered = renderCodexAgentToml(stripped);
    const expected = 'name = "msd-planner"\n' +
      'description = "Plans phases for MSD milestones"\n' +
      'model = "gpt-5.6-sol"\n' +
      "developer_instructions = '''\n" +
      'Plan the next phase.\n' +
      "'''\n";
    assert.equal(rendered, expected);
    assert.equal(stripped.reasoningEffort, null);
    assert.equal(stripped.model, 'gpt-5.6-sol', 'the model line must survive untouched');
  });

  test('stripModel() on a doc with no model line is a no-op copy', () => {
    const result = parseCodexAgentToml(A2_NO_HEADER_FIELDS);
    assert.equal(result.ok, true);
    const stripped = stripModel(result.doc);
    assert.equal(renderCodexAgentToml(stripped), A2_NO_HEADER_FIELDS);
  });

  test('stripReasoningEffort() on a doc with no effort line is a no-op copy', () => {
    const result = parseCodexAgentToml(A2_NO_HEADER_FIELDS);
    assert.equal(result.ok, true);
    const stripped = stripReasoningEffort(result.doc);
    assert.equal(renderCodexAgentToml(stripped), A2_NO_HEADER_FIELDS);
  });
});

// ─── A18-A24: mixed/edge line-ending round-trip (BLOCKER fix, per-line terminators) ──
//
// Regression coverage for the defect a review caught: `eol` used to be a
// single whole-file flag and `split(/\r?\n/)` discarded every line's own
// terminator, so `renderCodexAgentToml` re-joined with ONE style and
// normalized every line — even when zero strips were performed. None of
// A1-A17 exercised a MIXED-ending source (A12 is pure CRLF), so this gap
// shipped untested. These fixtures are hand-authored (never emitted by
// `generateCodexAgentToml`), per CONTRIBUTING's fixture-provenance rule.

const A18_MIXED_EOL = 'name = "msd-mixed"\r\n' +
  'model = "sonnet"\n' +
  'description = "mixed line endings"\r\n' +
  "developer_instructions = '''\n" +
  'Work.\r\n' +
  "'''\n";

const A20_LONE_CR = 'name = "msd-oldmac"\r' +
  'model = "sonnet"\n' +
  "developer_instructions = '''\n" +
  'Work.\n' +
  "'''\n";

const A21_NO_TRAILING_AFTER_BLOCK = 'name = "msd-terse2"\n' +
  "developer_instructions = '''\n" +
  'Work.\n' +
  "'''"; // no trailing newline at all — last line is the block's closing '''

const A22_MULTI_TRAILING_NEWLINES = 'name = "msd-multi"\n' +
  'model = "sonnet"\n' +
  "developer_instructions = '''\n" +
  'Work.\n' +
  "'''\n\n\n"; // three trailing newlines after the closing '''

const A23_BOM_ONLY = String.fromCharCode(0xfeff); // a file that is ONLY a BOM

const A24_EMPTY = ''; // a genuinely empty file

describe('A18-A24 (BLOCKER regression): mixed/edge line-ending round-trip', () => {
  test('A18: mixed \\r\\n and \\n in one file, unmodified — round-trips byte-identically', () => {
    const result = parseCodexAgentToml(A18_MIXED_EOL);
    assert.equal(result.ok, true);
    assert.equal(result.doc.model, 'sonnet');
    // Each line's own terminator is captured, never collapsed to one style.
    // No phantom trailing '' entry: the file has exactly 6 content lines, and
    // `terminators[i]` is the terminator that follows `lines[i]`, so the
    // arrays are the same length as the file's real line count.
    assert.deepEqual(result.doc.terminators, ['\r\n', '\n', '\r\n', '\n', '\r\n', '\n']);
    const rendered = renderCodexAgentToml(result.doc);
    assert.equal(rendered, A18_MIXED_EOL, 'mixed-EOL source must round-trip byte-identically, unmodified');
  });

  test('A19: mixed endings + a stale pin stripped — the pin\'s line (and only its own terminator) goes, every other line keeps its original terminator', () => {
    const result = parseCodexAgentToml(A18_MIXED_EOL);
    assert.equal(result.ok, true);
    const stripped = stripModel(result.doc);
    const rendered = renderCodexAgentToml(stripped);
    const expected = 'name = "msd-mixed"\r\n' +
      'description = "mixed line endings"\r\n' +
      "developer_instructions = '''\n" +
      'Work.\r\n' +
      "'''\n";
    assert.equal(rendered, expected, 'the model line (and its own \\n) must be gone; every surviving line keeps its own original terminator');
    assert.equal(stripped.model, null);
  });

  test('A20: a lone \\r (old-Mac style) somewhere in the file — preserved, not upgraded to \\r\\n or collapsed to \\n', () => {
    const result = parseCodexAgentToml(A20_LONE_CR);
    assert.equal(result.ok, true);
    assert.equal(result.doc.model, 'sonnet');
    assert.equal(result.doc.terminators[0], '\r', 'the lone CR must be recorded exactly, not merged with the following line');
    const rendered = renderCodexAgentToml(result.doc);
    assert.equal(rendered, A20_LONE_CR, 'must round-trip byte-identically, unmodified');
  });

  test('A21: last line is the block\'s closing \'\'\' with no trailing newline — round-trips byte-identically', () => {
    const result = parseCodexAgentToml(A21_NO_TRAILING_AFTER_BLOCK);
    assert.equal(result.ok, true);
    assert.equal(result.doc.trailingNewline, false);
    const rendered = renderCodexAgentToml(result.doc);
    assert.equal(rendered, A21_NO_TRAILING_AFTER_BLOCK);
  });

  test('A22: multiple trailing newlines — every one preserved, round-trips byte-identically', () => {
    const result = parseCodexAgentToml(A22_MULTI_TRAILING_NEWLINES);
    assert.equal(result.ok, true);
    assert.equal(result.doc.model, 'sonnet');
    const rendered = renderCodexAgentToml(result.doc);
    assert.equal(rendered, A22_MULTI_TRAILING_NEWLINES);
  });

  test('A23: a file that is only a BOM — parses, round-trips to just the BOM', () => {
    const result = parseCodexAgentToml(A23_BOM_ONLY);
    assert.equal(result.ok, true);
    assert.equal(result.doc.hadBOM, true);
    assert.equal(result.doc.model, null);
    const rendered = renderCodexAgentToml(result.doc);
    assert.equal(rendered, A23_BOM_ONLY);
  });

  test('A24: an empty file — parses, round-trips to an empty string', () => {
    const result = parseCodexAgentToml(A24_EMPTY);
    assert.equal(result.ok, true);
    assert.equal(result.doc.hadBOM, false);
    assert.equal(result.doc.model, null);
    const rendered = renderCodexAgentToml(result.doc);
    assert.equal(rendered, A24_EMPTY);
  });
});

// ─── A25-A28 (regression, B17): removeLine trailing-newline preservation ──────
//
// A stale/orphaned strip that lands on the file's LAST line must preserve
// (not invent, not drop) the file's trailing-newline status. The defect: a
// last-line removal used to keep the PREVIOUS line's own terminator, which
// only happens to be correct when every terminator in the file is identical
// (the common case, which is why A1-A24 never caught it) — it silently
// invents a trailing newline whenever the removed line's own terminator
// differs from the survivor's, e.g. no trailing newline at all (B17,
// commands.test.cjs), or a mixed-EOL source (A26 below).

describe('A25-A28 (regression, B17): removeLine preserves trailing-newline status', () => {
  test('A25 (red pre-fix): strip a model line that is the file\'s last line, no trailing newline — still no trailing newline', () => {
    const source = 'name = "msd-bare"\nmodel = "sonnet"'; // no trailing \n; model is the last line
    const result = parseCodexAgentToml(source);
    assert.equal(result.ok, true);
    assert.equal(result.doc.trailingNewline, false);
    const rendered = renderCodexAgentToml(stripModel(result.doc));
    // Pre-fix: removeLine kept the PREVIOUS line's terminator ('\n') instead
    // of the removed line's own ('') — rendered came back as
    // 'name = "msd-bare"\n', a trailing newline the source never had.
    assert.equal(rendered, 'name = "msd-bare"', 'the file must still have no trailing newline');
  });

  test('A26 (red pre-fix): strip a model line that is the file\'s last line, WITH a trailing newline — still exactly one trailing newline', () => {
    // Mixed EOL is deliberate: it is the only way to distinguish the two
    // candidate fixes. removeLine must inherit the removed line's
    // EMPTINESS (trailing-newline-or-not), never its STYLE — the survivor's
    // OWN terminator is already the right style for the survivor; copying
    // the removed line's terminator onto it would silently change the
    // survivor's own ending, which is exactly the class of defect the
    // mixed-EOL round-trip guarantee (A14) exists to prevent.
    const source = 'name = "msd-bare"\r\nmodel = "sonnet"\n'; // name: CRLF: model (last): LF
    const result = parseCodexAgentToml(source);
    assert.equal(result.ok, true);
    assert.equal(result.doc.trailingNewline, true);
    const rendered = renderCodexAgentToml(stripModel(result.doc));
    // Pre-fix (style-inheriting variant): rendered came back as
    // 'name = "msd-bare"\n' — the removed line's own LF terminator, which
    // silently changed the survivor's ending from CRLF to LF. Correct: the
    // survivor keeps its OWN CRLF terminator unchanged; the file still ends
    // with exactly one trailing newline, in the survivor's original style.
    assert.equal(rendered, 'name = "msd-bare"\r\n', 'exactly one trailing newline must survive, on the new last line, in ITS OWN style');
  });

  test('A27: strip the only line in a file — empty result', () => {
    // Already correct pre-fix (JS Array#slice(1) on a length-1 array is [],
    // so the old generic slice degenerated to the right answer here) —
    // included as a regression guard for the new length===1 branch, not
    // because it was red before the fix.
    const source = 'model = "sonnet"'; // one line, no trailing newline
    const result = parseCodexAgentToml(source);
    assert.equal(result.ok, true);
    assert.equal(result.doc.lines.length, 1);
    const stripped = stripModel(result.doc);
    assert.deepEqual(stripped.lines, []);
    assert.deepEqual(stripped.terminators, []);
    assert.equal(renderCodexAgentToml(stripped), '');
  });

  test('A28 (red pre-fix, row B7 shape): stale model plus its orphaned effort, effort is the last line, no trailing newline — both counts correct', () => {
    const source = 'name = "msd-stale"\nmodel = "opus"\nmodel_reasoning_effort = "medium"'; // no trailing \n
    const result = parseCodexAgentToml(source);
    assert.equal(result.ok, true);
    assert.equal(result.doc.trailingNewline, false);
    // Sequential removal, same order commands.test.cjs's syncCodex applies:
    // model first (a middle line — unaffected by the fix), then the now-last
    // orphaned effort line (the fix's compounding case).
    const afterModel = stripModel(result.doc);
    const afterBoth = stripReasoningEffort(afterModel);
    // Pre-fix: the second removal (now-last-line) kept the intermediate
    // survivor's terminator instead of the removed effort line's own,
    // rendering 'name = "msd-stale"\n' — a trailing newline the source
    // never had.
    assert.equal(renderCodexAgentToml(afterBoth), 'name = "msd-stale"', 'both lines gone AND no invented trailing newline');
    assert.equal(afterBoth.model, null);
    assert.equal(afterBoth.reasoningEffort, null);
  });

  test('A29 (regression, B7 shape, mixed EOL): stale model plus its orphaned effort, effort is the last line, mixed line endings — survivor keeps its OWN terminator, not the removed effort\'s', () => {
    // Exercises the two fixes' interaction: stripModel is a middle-line
    // removal (untouched by the last-line fix), then stripReasoningEffort
    // lands on the now-last line. Deliberately non-uniform EOL either side
    // of the second removal (survivor 'name' is CRLF-terminated, the
    // removed effort line is LF-terminated) so a style-inheriting bug and
    // the correct emptiness-inheriting behavior render DIFFERENT bytes.
    const source = 'name = "msd-stale"\r\nmodel = "opus"\nmodel_reasoning_effort = "medium"\n';
    const result = parseCodexAgentToml(source);
    assert.equal(result.ok, true);
    assert.equal(result.doc.trailingNewline, true);
    assert.deepEqual(result.doc.terminators, ['\r\n', '\n', '\n']);
    const afterModel = stripModel(result.doc);
    // Middle-line removal: splice only, no terminator fiddling — survivor
    // keeps its own '\r\n', the effort line keeps its own '\n'.
    assert.deepEqual(afterModel.terminators, ['\r\n', '\n']);
    const afterBoth = stripReasoningEffort(afterModel);
    // If the bug were still present (inheriting the removed effort line's
    // OWN '\n'), this would render 'name = "msd-stale"\n' — silently
    // downgrading the survivor's CRLF to LF. Correct: the survivor's own
    // '\r\n' is unchanged; the file still ends with exactly one trailing
    // newline.
    assert.equal(renderCodexAgentToml(afterBoth), 'name = "msd-stale"\r\n', 'survivor keeps its OWN terminator; no invented/altered line ending');
    assert.equal(afterBoth.model, null);
    assert.equal(afterBoth.reasoningEffort, null);
  });
});

// ─── A17: enum lock ────────────────────────────────────────────────────────

describe('PARSE_REASON enum', () => {
  test('A17: Object.keys(PARSE_REASON).sort() is locked and frozen', () => {
    assert.deepEqual(Object.keys(PARSE_REASON).sort(), ['UNTERMINATED_BLOCK']);
    assert.equal(PARSE_REASON.UNTERMINATED_BLOCK, 'unterminated_block');
    assert.ok(Object.isFrozen(PARSE_REASON));
  });
});