gstack/test/frontend-scope.test.ts

/**
 * lib/frontend-scope.ts mirrors the m_frontend arm of bin/gstack-diff-scope.
 * Pure cases run everywhere; the parity case runs the bash script in a temp
 * repo (POSIX only) so the two implementations cannot drift silently.
 */
import { describe, test, expect } from 'bun:test';
import * as fs from 'fs';
import * as os from 'os';
import * as path from 'path';
import { spawnSync } from 'child_process';
import { isFrontendPath } from '../lib/frontend-scope';

const ROOT = path.join(import.meta.dir, '..');
const POSIX = process.platform !== 'win32';

const SAMPLES: Array<[string, boolean]> = [
  ['src/components/Button.tsx', true],
  ['src/Button.jsx', true],
  ['pages/index.vue', true],
  ['app/Widget.svelte', true],
  ['site/page.astro', true],
  ['styles/main.css', true],
  ['css/a.scss', true],
  ['x/y/theme.less', true],
  ['x/a.sass', true],
  ['x/a.pcss', true],
  ['app/views/users/show.html.erb', true],
  ['templates/a.haml', true],
  ['templates/a.slim', true],
  ['templates/a.hbs', true],
  ['views/a.ejs', true],
  ['public/index.html', true],
  ['tailwind.config.js', true],
  ['postcss.config.cjs', true],
  ['app/assets/stylesheets/app.css', true],
  ['lib/util/components/helper.rb', true],
  ['lib/server.ts', false],
  ['src/api/route.js', false],
  ['README.md', false],
  ['package.json', false],
  ['test/foo.test.ts', false],
  ['components.md', false],
];

describe('isFrontendPath', () => {
  test.each(SAMPLES)('%s → %p', (p, expected) => {
    expect(isFrontendPath(p)).toBe(expected);
  });

  test('normalizes leading ./ and backslashes', () => {
    expect(isFrontendPath('./styles/a.css')).toBe(true);
    expect(isFrontendPath('src\\components\\A.tsx')).toBe(true);
  });
});

describe.skipIf(!POSIX)('parity with bin/gstack-diff-scope', () => {
  test('SCOPE_FRONTEND agrees with isFrontendPath for every sample, one file per diff', () => {
    const dir = fs.mkdtempSync(path.join(os.tmpdir(), 'gstack-scope-parity-'));
    const git = (...a: string[]) => {
      const r = spawnSync('git', a, { cwd: dir, encoding: 'utf-8' });
      if (r.status !== 0) throw new Error(r.stderr);
    };
    try {
      git('init', '-q', '-b', 'main');
      git('config', 'user.email', 't@example.com');
      git('config', 'user.name', 't');
      fs.writeFileSync(path.join(dir, 'base.txt'), 'x\n');
      git('add', '-A'); git('commit', '-q', '-m', 'base');
      const mismatches: string[] = [];
      for (const [rel, expected] of SAMPLES) {
        git('checkout', '-q', '-b', 'probe');
        const full = path.join(dir, rel);
        fs.mkdirSync(path.dirname(full), { recursive: true });
        fs.writeFileSync(full, '/* x */\n');
        git('add', '-A'); git('commit', '-q', '-m', rel);
        const r = spawnSync('bash', [path.join(ROOT, 'bin', 'gstack-diff-scope'), 'main'], { cwd: dir, encoding: 'utf-8' });
        const bashSays = /SCOPE_FRONTEND=true/.test(r.stdout);
        if (bashSays !== expected) mismatches.push(`${rel}: bash=${bashSays} ts=${expected}`);
        git('checkout', '-q', 'main'); git('branch', '-q', '-D', 'probe');
      }
      expect(mismatches).toEqual([]);
    } finally {
      fs.rmSync(dir, { recursive: true, force: true });
    }
  });
});