diff --git a/phpunit.xml.dist b/phpunit.xml.dist
index 0263dbb..7557d37 100644
--- a/phpunit.xml.dist
+++ b/phpunit.xml.dist
@@ -1,5 +1,10 @@
 <?xml version="1.0" encoding="UTF-8"?>
-<phpunit xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" bootstrap="./tests/bootstrap.php" colors="true" xsi:noNamespaceSchemaLocation="https://schema.phpunit.de/10.5/phpunit.xsd">
+<phpunit xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" bootstrap="./tests/bootstrap.php" colors="true" xsi:noNamespaceSchemaLocation="./vendor/phpunit/phpunit/phpunit.xsd">
+  <source>
+    <include>
+      <directory suffix=".php">src/</directory>
+    </include>
+  </source>
   <coverage>
     <report>
       <clover outputFile="build/logs/clover.xml"/>