diff --git a/test/tiles_rendered.js b/test/tiles_rendered.js
index 6f7f438..6a963cc 100644
--- a/test/tiles_rendered.js
+++ b/test/tiles_rendered.js
@@ -1,3 +1,5 @@
+import path from 'path';
+
 var testTile = function (
   prefix,
   tileSize = 256,
@@ -10,19 +12,7 @@ var testTile = function (
   type,
 ) {
   if (scale) y += '@' + scale + 'x';
-  var path =
-    '/styles/' +
-    prefix +
-    '/' +
-    tileSize +
-    '/' +
-    z +
-    '/' +
-    x +
-    '/' +
-    y +
-    '.' +
-    format;
+  var path = path.join('/styles', prefix, tileSize, z, x, `${y}.${format}`);
   it(path + ' returns ' + status, function (done) {
     var test = supertest(app).get(path);
     test.expect(status);