diff --git a/tests/Unit/Crypt/AES/TestCase.php b/tests/Unit/Crypt/AES/TestCase.php
index 8bc8bc41..baa7d1e6 100644
--- a/tests/Unit/Crypt/AES/TestCase.php
+++ b/tests/Unit/Crypt/AES/TestCase.php
@@ -203,7 +203,7 @@ abstract class Unit_Crypt_AES_TestCase extends PhpseclibTestCase
 
         $c2 = $result;
 
-        $this->assertSame(bin2hex($c1), bin2hex($c2));
+        $this->assertSame(bin2hex($c1), bin2hex($c2), "{$this->engine} produced different results for '$op' in $mode with " . implode(',', $test));
     }
 
     /**