diff --git a/tests/phpunit.xml b/tests/phpunit.xml
index fc7e572..9385f82 100644
--- a/tests/phpunit.xml
+++ b/tests/phpunit.xml
@@ -1,4 +1,6 @@
 <phpunit
+		xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+		xsi:noNamespaceSchemaLocation="../vendor/phpunit/phpunit/phpunit.xsd"
 		bootstrap="bootstrap.php"
 		colors="true"
 		backupGlobals="false"