diff --git a/test/PHPMailer/PHPMailerTest.php b/test/PHPMailer/PHPMailerTest.php
index 0b82fe12..497476a5 100644
--- a/test/PHPMailer/PHPMailerTest.php
+++ b/test/PHPMailer/PHPMailerTest.php
@@ -1258,13 +1258,12 @@ EOT;
         $this->Mail->smtpClose();
     }
 
+    /**
+     * @requires extension mbstring
+     * @requires function idn_to_ascii
+     */
     public function testGivenIdnAddress_addAddress_returns_true()
     {
-        if (file_exists(\PHPMAILER_INCLUDE_DIR . '/test/fakefunctions.php') === false) {
-            $this->markTestSkipped('/test/fakefunctions.php file not found');
-        }
-
-        include \PHPMAILER_INCLUDE_DIR . '/test/fakefunctions.php';
         $this->assertTrue($this->Mail->addAddress('test@françois.ch'));
     }
 
diff --git a/test/fakefunctions.php b/test/fakefunctions.php
deleted file mode 100644
index 134da600..00000000
--- a/test/fakefunctions.php
+++ /dev/null
@@ -1,15 +0,0 @@
-<?php
-
-if (!function_exists('idn_to_ascii')) {
-    function idn_to_ascii()
-    {
-        return true;
-    }
-}
-
-if (!function_exists('mb_convert_encoding')) {
-    function mb_convert_encoding()
-    {
-        return true;
-    }
-}