fix: harden unicode safety checks

tests/scripts/check-unicode-safety.test.js

@@ -0,0 +1,83 @@
+const assert = require('assert');
+const fs = require('fs');
+const os = require('os');
+const path = require('path');
+const { spawnSync } = require('child_process');
+
+const scriptPath = path.join(__dirname, '..', '..', 'scripts', 'ci', 'check-unicode-safety.js');
+
+function test(name, fn) {
+  try {
+    fn();
+    console.log(`PASS: ${name}`);
+    return true;
+  } catch (error) {
+    console.log(`FAIL: ${name}`);
+    console.log(`  ${error.message}`);
+    return false;
+  }
+}
+
+function runCheck(root, args = []) {
+  return spawnSync('node', [scriptPath, ...args], {
+    env: {
+      ...process.env,
+      ECC_UNICODE_SCAN_ROOT: root,
+    },
+    encoding: 'utf8',
+  });
+}
+
+function makeTempRoot(prefix) {
+  return fs.mkdtempSync(path.join(os.tmpdir(), prefix));
+}
+
+const warningEmoji = String.fromCodePoint(0x26A0, 0xFE0F);
+const toolsEmoji = String.fromCodePoint(0x1F6E0, 0xFE0F);
+const zeroWidthSpace = String.fromCodePoint(0x200B);
+
+let passed = 0;
+let failed = 0;
+
+if (
+  test('fails on invisible unicode and emoji before cleanup', () => {
+    const root = makeTempRoot('ecc-unicode-check-');
+    fs.mkdirSync(path.join(root, 'docs'), { recursive: true });
+    fs.mkdirSync(path.join(root, 'scripts'), { recursive: true });
+    fs.writeFileSync(path.join(root, 'docs', 'guide.md'), `> ${warningEmoji} Important launch note\n`);
+    fs.writeFileSync(path.join(root, 'scripts', 'sample.js'), `const x = "a${zeroWidthSpace}";\n`);
+
+    const result = runCheck(root);
+    assert.notStrictEqual(result.status, 0, result.stdout + result.stderr);
+    assert.match(result.stderr, /dangerous-invisible U\+200B/);
+    assert.match(result.stderr, /emoji U\+26A0/);
+  })
+)
+  passed++;
+else failed++;
+
+if (
+  test('write mode removes emoji and invisible unicode', () => {
+    const root = makeTempRoot('ecc-unicode-fix-');
+    fs.mkdirSync(path.join(root, 'docs'), { recursive: true });
+    fs.writeFileSync(path.join(root, 'docs', 'guide.md'), `> ${warningEmoji} Important launch note\n`);
+    fs.writeFileSync(path.join(root, 'README.md'), `## ${toolsEmoji} Tools\n`);
+    fs.writeFileSync(path.join(root, 'note.txt'), `one${zeroWidthSpace}two\n`);
+
+    const writeResult = runCheck(root, ['--write']);
+    assert.strictEqual(writeResult.status, 0, writeResult.stdout + writeResult.stderr);
+
+    assert.strictEqual(fs.readFileSync(path.join(root, 'docs', 'guide.md'), 'utf8'), '> WARNING: Important launch note\n');
+    assert.strictEqual(fs.readFileSync(path.join(root, 'README.md'), 'utf8'), '## Tools\n');
+    assert.strictEqual(fs.readFileSync(path.join(root, 'note.txt'), 'utf8'), 'onetwo\n');
+
+    const cleanResult = runCheck(root);
+    assert.strictEqual(cleanResult.status, 0, cleanResult.stdout + cleanResult.stderr);
+  })
+)
+  passed++;
+else failed++;
+
+console.log(`\nPassed: ${passed}`);
+console.log(`Failed: ${failed}`);
+process.exit(failed > 0 ? 1 : 0);