diff --git a/core/tests/Drupal/FunctionalJavascriptTests/JSWebAssert.php b/core/tests/Drupal/FunctionalJavascriptTests/JSWebAssert.php
index 94a9108..ae67c52 100644
--- a/core/tests/Drupal/FunctionalJavascriptTests/JSWebAssert.php
+++ b/core/tests/Drupal/FunctionalJavascriptTests/JSWebAssert.php
@@ -26,7 +26,21 @@ class JSWebAssert extends WebAssert {
    *   be displayed.
    */
   public function assertWaitOnAjaxRequest($timeout = 10000, $message = 'Unable to complete AJAX request.') {
-    $result = $this->session->wait($timeout, '(typeof(jQuery)=="undefined" || (0 === jQuery.active && 0 === jQuery(\':animated\').length))');
+    $condition = <<<JS
+      (function() {
+        function IsNotAjaxing(instance, index, array) {
+          "use strict";
+          return instance ? !instance.ajaxing : true;
+        }
+        return (
+          // Assert no AJAX request is running (via jQuery or Drupal) and no 
+          // animation is running.
+          (typeof jQuery === "undefined" || (jQuery.active === 0 && jQuery(':animated').length === 0)) &&
+          (typeof Drupal === 'undefined' || typeof Drupal.ajax === 'undefined' || Drupal.ajax.instances.every(IsNotAjaxing))
+        );
+      }());
+JS;
+    $result = $this->session->wait($timeout, $condition);
     if (!$result) {
       throw new \RuntimeException($message);
     }
@@ -38,9 +52,9 @@ public function assertWaitOnAjaxRequest($timeout = 10000, $message = 'Unable to
    * @see https://api.jqueryui.com/autocomplete/#option-delay
    */
   public function waitOnAutocomplete() {
-    // Drupal is using the default delay value of 300 milliseconds.
-    $this->session->wait(300);
-    $this->assertWaitOnAjaxRequest();
+    // Wait for the autocomplete to be visible.
+    $condition = "(jQuery('.ui-autocomplete:visible li').length > 0)";
+    return $this->session->wait(10000, $condition);
   }
 
   /**