diff --git a/core/modules/system/src/Tests/Common/CascadingStylesheetsTest.php b/core/modules/system/src/Tests/Common/CascadingStylesheetsTest.php
index 97b1fc6..4537019 100644
--- a/core/modules/system/src/Tests/Common/CascadingStylesheetsTest.php
+++ b/core/modules/system/src/Tests/Common/CascadingStylesheetsTest.php
@@ -78,7 +78,7 @@ function testRenderFile() {
     $this->assertTrue(strpos($styles, $css) > 0, 'Rendered CSS includes the added stylesheet.');
     // Verify that newlines are properly added inside style tags.
     $query_string = $this->container->get('state')->get('system.css_js_query_string') ?: '0';
-    $css_processed = '<link rel="stylesheet" href="' . check_plain(file_create_url($css)) . "?" . $query_string . '" media="all" />';
+    $css_processed = '<link rel="stylesheet" href="' . check_plain(file_create_url($css)) . "?" . $query_string . '" media="all">';
     $this->assertEqual(trim($styles), $css_processed, 'Rendered CSS includes newlines inside style tags for JavaScript use.');
   }