diff --git a/apps/dav/tests/unit/bootstrap.php b/apps/dav/tests/unit/bootstrap.php
index 28f6b971de..b6ea48ec90 100644
--- a/apps/dav/tests/unit/bootstrap.php
+++ b/apps/dav/tests/unit/bootstrap.php
@@ -1,6 +1,8 @@
 <?php
 
-define('PHPUNIT_RUN', 1);
+if (!defined('PHPUNIT_RUN')) {
+	define('PHPUNIT_RUN', 1);
+}
 
 require_once __DIR__.'/../../../../lib/base.php';