diff --git a/tests/TestCase.php b/tests/TestCase.php
index d53a18c7..5dae9641 100644
--- a/tests/TestCase.php
+++ b/tests/TestCase.php
@@ -162,7 +162,7 @@ abstract class TestCase extends \Orchestra\Testbench\TestCase
 
     public function randomString(int $length = 10)
     {
-        return \substr(\str_shuffle(\str_repeat($x = '0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ', \ceil($length / \strlen($x)))), 1, $length);
+        return \substr(\str_shuffle(\str_repeat($x = '0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ', (int) (\ceil($length / \strlen($x))))), 1, $length);
     }
 
     public function isContainerized()