diff --git a/tests/acceptance/_bootstrap.php b/tests/acceptance/_bootstrap.php
index 05a2fb79e2..c2b2f2ad91 100644
--- a/tests/acceptance/_bootstrap.php
+++ b/tests/acceptance/_bootstrap.php
@@ -1,3 +1,6 @@
 <?php
-define("TIMEOUT", 60);
-?>
\ No newline at end of file
+
+if (!defined('TIMEOUT'))
+{
+	define("TIMEOUT", 60);
+}