From 9f34222aa5da59a775b2f7474651f1f27eb7b4f6 Mon Sep 17 00:00:00 2001
From: Pieter Frenssen <pieter@frenssen.be>
Date: Tue, 5 Feb 2019 15:46:08 +0100
Subject: [PATCH] Throw a helpful exception if the AJAX timeout is missing due
 to a common mistake in the configuration.

---
 src/Drupal/DrupalExtension/Context/MinkContext.php | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/src/Drupal/DrupalExtension/Context/MinkContext.php b/src/Drupal/DrupalExtension/Context/MinkContext.php
index b7bf9e1c..e7815496 100644
--- a/src/Drupal/DrupalExtension/Context/MinkContext.php
+++ b/src/Drupal/DrupalExtension/Context/MinkContext.php
@@ -152,7 +152,11 @@ function isAjaxing(instance) {
       );
     }());
 JS;
-        $result = $this->getSession()->wait(1000 * $this->getMinkParameter('ajax_timeout'), $condition);
+        $ajax_timeout = $this->getMinkParameter('ajax_timeout');
+        if ($ajax_timeout === NULL) {
+          throw new \Exception('No AJAX timeout has been defined. Please verify that "Drupal\MinkExtension" is configured in behat.yml (and not "Behat\MinkExtension").');
+        }
+        $result = $this->getSession()->wait(1000 * $ajax_timeout, $condition);
         if (!$result) {
             if ($event) {
                 /** @var \Behat\Behat\Hook\Scope\BeforeStepScope $event */