diff -u b/core/tests/Drupal/FunctionalJavascriptTests/JavascriptTestBase.php b/core/tests/Drupal/FunctionalJavascriptTests/JavascriptTestBase.php
--- b/core/tests/Drupal/FunctionalJavascriptTests/JavascriptTestBase.php
+++ b/core/tests/Drupal/FunctionalJavascriptTests/JavascriptTestBase.php
@@ -63,7 +63,7 @@
       //@todo Remove when https://github.com/jcalderonzumba/gastonjs/issues/19
       // is fixed. Currently clicking anchors/buttons with nested elements is
       // not possible, which is why we use Javascript's native click method.
-      $css_selector = addcslashes($css_selector, "''");
+      $css_selector = addcslashes($css_selector, "'");
       $this->getSession()->executeScript("document.querySelectorAll('" . $css_selector . "')[0].click()");
     }
   }