diff --git a/build/phpunit.xml b/build/phpunit.xml
index 517c342a..5b44b45c 100644
--- a/build/phpunit.xml
+++ b/build/phpunit.xml
@@ -17,6 +17,7 @@
 			<directory suffix=".php">PHP_LIBDIR</directory>
 			<directory suffix=".php">../vendor/composer</directory>
 			<directory suffix=".php">../vendor/mockery</directory>
+			<directory suffix=".php">../vendor/phpunit</directory>
 			<directory suffix=".php">../tests</directory>
 			<directory suffix=".php">../testing</directory>
 		</blacklist>