commit 73543f1479cbf97f44a937a4c7a0f448f3e1fde4
Author: Joel Pittet <joel@pittet.ca>
Date:   Tue Aug 18 12:12:15 2015 -0700

    implode

diff --git a/core/modules/system/src/Tests/Form/ValidationTest.php b/core/modules/system/src/Tests/Form/ValidationTest.php
index d2e31c9..246fb68 100644
--- a/core/modules/system/src/Tests/Form/ValidationTest.php
+++ b/core/modules/system/src/Tests/Form/ValidationTest.php
@@ -292,11 +292,8 @@ protected function assertErrorMessages($messages) {
       $error_links[] = \Drupal::l($message['title'], Url::fromRoute('<none>', [], ['fragment' => 'edit-' . str_replace('_', '-', $message['key']), 'external' => TRUE]));
     }
     $top_message = \Drupal::translation()->formatPlural(count($error_links), '1 error has been found:', '@count errors have been found:');
-    $this->assertRaw($top_message);
+    $this->assertRaw($top_message . ' ' . implode(', ', $error_links));
     $this->assertNoText('An illegal choice has been detected. Please contact the site administrator.');
-    foreach ($error_links as $link) {
-      $this->assertRaw($link);
-    }
   }
 
 }