diff -u b/core/tests/Drupal/FunctionalJavascriptTests/JSWebAssert.php b/core/tests/Drupal/FunctionalJavascriptTests/JSWebAssert.php
--- b/core/tests/Drupal/FunctionalJavascriptTests/JSWebAssert.php
+++ b/core/tests/Drupal/FunctionalJavascriptTests/JSWebAssert.php
@@ -70,14 +70,18 @@
           }
         }
 
+        if (typeof Drupal === 'undefined') {
+          return true;
+        }
+        
         return (
           (
             typeof jQuery == "undefined" || (
-              jQuery.active === 0 && 
+              jQuery.active === 0 &&
               jQuery(':animated').length === 0
             )
-          ) && 
-          (typeof Drupal.debounceCount === 'undefined' || Drupal.debounceCount === 0) && 
+          ) &&
+          (typeof Drupal.debounceCount === 'undefined' || Drupal.debounceCount === 0) &&
           Drupal.ajax.instances.every(IsNotAjaxing)
         );
       }());