diff --git a/src/Symfony/Component/Console/Tests/Helper/ProgressBarTest.php b/src/Symfony/Component/Console/Tests/Helper/ProgressBarTest.php
index 8f33e3bf37..51962f3d16 100644
--- a/src/Symfony/Component/Console/Tests/Helper/ProgressBarTest.php
+++ b/src/Symfony/Component/Console/Tests/Helper/ProgressBarTest.php
@@ -492,6 +492,9 @@ class ProgressBarTest extends \PHPUnit_Framework_TestCase
         );
     }
 
+    /**
+     * @requires extension mbstring
+     */
     public function testAnsiColorsAndEmojis()
     {
         $bar = new ProgressBar($output = $this->getOutputStream(), 15);