diff --git a/tests/phpunit.xml b/tests/phpunit.xml
index 82592a2..968698f 100644
--- a/tests/phpunit.xml
+++ b/tests/phpunit.xml
@@ -6,6 +6,7 @@
   convertErrorsToExceptions="true"
   convertNoticesToExceptions="true"
   convertWarningsToExceptions="true"
+  convertDeprecationsToExceptions="true"
   beStrictAboutTestsThatDoNotTestAnything="true"
   beStrictAboutOutputDuringTests="true"
   xsi:noNamespaceSchemaLocation="https://schema.phpunit.de/9.3/phpunit.xsd"