config-audit/tests/commands/subtraction-write-shape.test.mjs

/**
 * SUB-WRITE caller arm — `optimize --subtract --apply` (#63).
 *
 * #45/#46/#47 all taught the same lesson: fixing a CLI does not fix the command
 * that reads its payload. A gate the engine enforces is worth nothing to the
 * user if the template never renders the disclosure, and a refusal the payload
 * reports is invisible if the template only ever prints successes.
 *
 * This arm is deliberately NOT folded into `write-scope-gate-shape.test.mjs`.
 * Those five commands classify their targets with `write-scope-cli.mjs` and
 * then honour the answer in prose; this one hands its targets to a CLI that
 * refuses the write itself. Requiring it to ALSO call `write-scope-cli.mjs`
 * would classify the same paths twice, which is the copy the class table exists
 * to prevent.
 */

import { test } from 'node:test';
import { strict as assert } from 'node:assert';
import { readFile, readdir } from 'node:fs/promises';
import { resolve, dirname } from 'node:path';
import { fileURLToPath } from 'node:url';

const __dirname = dirname(fileURLToPath(import.meta.url));
const COMMANDS_DIR = resolve(__dirname, '..', '..', 'commands');

const optimizeMd = async () => await readFile(resolve(COMMANDS_DIR, 'optimize.md'), 'utf-8');

/**
 * Completeness derived from the catalog rather than from a literal: it is the
 * NEXT command to drive the removal CLI that is at risk, not this one (#57/#62
 * — a hand-maintained sweep list is a premise, not a measurement).
 */
async function commandsDrivingTheRemovalCli() {
  const out = [];
  for (const name of await readdir(COMMANDS_DIR)) {
    if (!name.endsWith('.md')) continue;
    const content = await readFile(resolve(COMMANDS_DIR, name), 'utf-8');
    if (content.includes('subtraction-write-cli.mjs')) out.push({ name, content });
  }
  return out;
}

test('the removal CLI has at least one caller — otherwise this whole arm is vacuous', async () => {
  const callers = await commandsDrivingTheRemovalCli();
  assert.ok(
    callers.length >= 1,
    'No command drives subtraction-write-cli.mjs. Every assertion below would pass over an\n' +
      'empty list, which is how a caller-arm guard goes green on a feature nobody can reach.',
  );
});

test('every caller anchors the CLI and keeps its payload off the screen', async () => {
  for (const { name, content } of await commandsDrivingTheRemovalCli()) {
    assert.match(
      content,
      /\$\{CLAUDE_PLUGIN_ROOT\}\/scanners\/subtraction-write-cli\.mjs/,
      `${name} must anchor the CLI at \${CLAUDE_PLUGIN_ROOT} — a relative path resolves against\n` +
        "the user's working directory, and this one deletes configuration.",
    );
    assert.match(
      content,
      /subtraction-write-cli\.mjs[^\n]*--output-file[^\n]*2>\/dev\/null/,
      `${name} must invoke it as \`--output-file <path> 2>/dev/null\` (ux-rules rule 2).`,
    );
  }
});

test('every caller dry-runs before it writes', async () => {
  for (const { name, content } of await commandsDrivingTheRemovalCli()) {
    assert.match(
      content,
      /--dry-run/,
      `${name} writes without proving the spans still match first. A stale approval is the\n` +
        'expected case here — the file may have been edited since the scan.',
    );
  }
});

test('every caller surfaces the scope gate in the user\'s words', async () => {
  for (const { name, content } of await commandsDrivingTheRemovalCli()) {
    assert.match(
      content,
      /requiresApproval/,
      `${name} must branch on \`requiresApproval\`. The engine refuses the write, but a template\n` +
        'that never asks leaves the user staring at a run that did nothing.',
    );
    assert.match(
      content,
      /disclosures/,
      `${name} must render the payload's \`disclosures[]\` verbatim. Wording paraphrased per\n` +
        'command is a policy copy that drifts.',
    );
    // Whitespace-tolerant: markdown wraps, and a bare space would let line
    // length decide green/red (#62, [[guard-can-be-green-on-its-own-defect]]).
    assert.match(
      content,
      /every\s+project/,
      `${name} must say, in words, that a machine-wide removal costs and saves in every project.\n` +
        'The class name alone is vocabulary the user has not been taught.',
    );
  }
});

test('every caller reports refusals with their reason, not just successes', async () => {
  for (const { name, content } of await commandsDrivingTheRemovalCli()) {
    assert.match(
      content,
      /refused/,
      `${name} must report the payload's \`refused\` entries. A removal silently dropped reads\n` +
        'as a removal that happened.',
    );
    for (const reason of ['block-mismatch', 'floor']) {
      assert.ok(
        content.includes(reason),
        `${name} must explain \`${reason}\` — the two reasons a user can actually act on. One\n` +
          'means re-run the scan, the other means the block is load-bearing and never goes.',
      );
    }
  }
});

test('every caller tells the user how to undo the removal', async () => {
  for (const { name, content } of await commandsDrivingTheRemovalCli()) {
    assert.match(
      content,
      /backupId/,
      `${name} must surface the backup id from the payload.`,
    );
    assert.match(
      content,
      /config-audit\s+rollback/,
      `${name} must name the command that restores the file. A backup nobody is told about is\n` +
        'not a safety net.',
    );
  }
});

test('the subtraction copy does not oversell the saving', async () => {
  // Measured in the #40 fasit: ~1 400 deletable tokens, ~850 after tier-2
  // earn-backs, against a ~4 300-token file — a fifth, not most of it. Copy
  // that implies more is a defect of this feature, not a rounding difference.
  const content = await optimizeMd();
  // No trailing `\b` after the percent alternative: `%` is a non-word
  // character, so `\b` there demands a word character NEXT — and "80% of the
  // file" has a space. Measured green against exactly that mutation before the
  // anchor was dropped; the same ASCII-only `\b` trap as `/\bunngå\b/`.
  assert.doesNotMatch(
    content,
    /most\s+of\s+(?:the|your)\s+(?:file|config)|majority\s+of\s+(?:the|your)\s+file|\b(?:[5-9]\d|100)\s*%/i,
    'optimize.md implies the subtraction axis removes most of a CLAUDE.md. The measured figure\n' +
      'is around a fifth, and the honest number is the whole point of a deletion feature.',
  );
});

test('optimize.md still says what runs without --apply', async () => {
  const content = await optimizeMd();
  assert.match(
    content,
    /Without\s+`--apply`,\s+no\s+files\s+are\s+modified/,
    'The default must stay stated: `--subtract` alone proposes. A reader who skims the flag\n' +
      'list needs to know which half of the axis writes.',
  );
});