diff --git a/core/modules/simpletest/lib/Drupal/simpletest/WebTestBase.php b/core/modules/simpletest/lib/Drupal/simpletest/WebTestBase.php
index 138bf34..c66ba07 100644
--- a/core/modules/simpletest/lib/Drupal/simpletest/WebTestBase.php
+++ b/core/modules/simpletest/lib/Drupal/simpletest/WebTestBase.php
@@ -1934,7 +1934,8 @@ protected function assertNoLinkByHref($href, $message = '', $group = 'Other') {
    */
   protected function clickLink($label, $index = 0) {
     $url_before = $this->getUrl();
-    $urls = $this->xpath('//a[normalize-space(text())=:label]', array(':label' => $label));
+    // Replace the text to lowercase, so that clickLink() is not case sensitive.
+    $urls = $this->xpath("//a[normalize-space(translate(text(), 'ABCDEFGHIJKLMNOPQRSTUVWXYZ', 'abcdefghijklmnopqrstuvwxyz'))=:label]", array(':label' => strtolower($label)));
 
     if (isset($urls[$index])) {
       $url_target = $this->getAbsoluteUrl($urls[$index]['href']);