diff --git a/tests/ExtensionTest.php b/tests/ExtensionTest.php
index 95431dfdd..10c09fb3b 100644
--- a/tests/ExtensionTest.php
+++ b/tests/ExtensionTest.php
@@ -20,5 +20,6 @@ class ExtensionTest extends \PHPUnit\Framework\TestCase
         self::assertTrue(extension_loaded('mbstring'));
         self::assertTrue(extension_loaded('curl'));
         self::assertTrue(extension_loaded('imap'));
+        self::assertTrue(extension_loaded('gd2'));
     }
 }