added check for phpunit 5.7 fallback

updated doc-block

Author: kokspflanze

test/_autoload.php

@@ -1,10 +1,12 @@
 <?php
 /**
- * @see       https://github.com/zendframework/zend-component-installer for the canonical source repository
+ * @link      http://github.com/zendframework/zend-eventmanager for the canonical source repository
  * @copyright Copyright (c) 2017 Zend Technologies USA Inc. (http://www.zend.com)
- * @license   https://github.com/zendframework/zend-component-installer/blob/master/LICENSE.md New BSD License
+ * @license   https://github.com/zendframework/zend-eventmanager/blob/master/LICENSE.md
  */
 
 use PHPUnit\Framework\ExpectationFailedException;
 
-class_alias('PHPUnit_Framework_ExpectationFailedException', ExpectationFailedException::class);
+if (class_exists('PHPUnit_Framework_ExpectationFailedException')) {
+    class_alias('PHPUnit_Framework_ExpectationFailedException', ExpectationFailedException::class);
+}