diff --git a/core/modules/rest/lib/Drupal/rest/Tests/RESTTestBase.php b/core/modules/rest/lib/Drupal/rest/Tests/RESTTestBase.php
index 1e19be2..3ae7faf 100644
--- a/core/modules/rest/lib/Drupal/rest/Tests/RESTTestBase.php
+++ b/core/modules/rest/lib/Drupal/rest/Tests/RESTTestBase.php
@@ -79,6 +79,7 @@ protected function httpRequest($url, $method, $body = NULL, $mime_type = NULL) {
       // GET the CSRF token first for writing requests.
       $token = $this->drupalGet('rest/session/token');
     }
+    $curl_options = array();
     switch ($method) {
       case 'GET':
         // Set query if there are additional GET parameters.