test(nominatim): share one POSIX guard and say the cache is private only on POSIX

Co-Authored-By: Claude Opus 5.5 <[email protected]>

src/tooling/nominatimOutlineRoute.test.mjs

@@ -684,29 +684,34 @@ test('the disk cache survives a restart and stays within its bounds', async () =
     await createNominatimCache({ dir, now: time.now }).get('k0'),
     null,
   );
-  // Windows has no POSIX mode bits (directories stat as 0o666), so only
+  // The cache is private only through POSIX mode bits. Windows has none
-  // POSIX systems can check privacy this way.
+  // (directories stat as 0o666) and the cache keeps the checkout's ACLs,
-  if (process.platform !== 'win32')
+  // so these checks run, and privacy holds, only on POSIX systems.
+  const posixModes = process.platform !== 'win32';
+  if (posixModes) {
     assert.equal(
       fs.statSync(dir).mode & 0o777,
       0o700,
-      'the query cache directory is private',
+      'the query cache directory is private (POSIX modes)',
     );
+  }
   const text = fs
     .readdirSync(dir)
     .filter((name) => name.endsWith('.json'))
     .map((name) => fs.readFileSync(path.join(dir, name), 'utf8'))
     .join('\n');
   assert.equal(text.includes('k4'), false, 'disk entries never store raw keys');
-  if (process.platform !== 'win32')
+  if (posixModes) {
     for (const name of fs
       .readdirSync(dir)
-      .filter((entry) => entry.endsWith('.json')))
+      .filter((entry) => entry.endsWith('.json'))) {
       assert.equal(
         fs.statSync(path.join(dir, name)).mode & 0o777,
         0o600,
-        `${name} is private`,
+        `${name} is private (POSIX modes)`,
       );
+    }
+  }
   fs.rmSync(dir, { recursive: true, force: true });
 });