commit 6e7b1c60f2b4115c5e8c966697535a21316ae7ec
Author: Joel Pittet <joel@pittet.ca>
Date:   Tue Sep 8 10:19:22 2015 -0700

    missing period and space

diff --git a/core/modules/system/tests/modules/cache_test/src/Controller/CacheTestController.php b/core/modules/system/tests/modules/cache_test/src/Controller/CacheTestController.php
index e49e45e..f47c057 100644
--- a/core/modules/system/tests/modules/cache_test/src/Controller/CacheTestController.php
+++ b/core/modules/system/tests/modules/cache_test/src/Controller/CacheTestController.php
@@ -22,7 +22,7 @@ class CacheTestController {
   public function urlBubbling() {
     $url = Url::fromRoute('<current>')->setAbsolute();
     return [
-      '#markup' => 'This URL is early-rendered: ' . $url->toString() . 'Yet, its bubbleable metadata should be bubbled.',
+      '#markup' => 'This URL is early-rendered: ' . $url->toString() . '. Yet, its bubbleable metadata should be bubbled.',
     ];
   }