diff --git a/phpunit.xml b/phpunit.xml
index 21f17685b..b72c6e5f1 100644
--- a/phpunit.xml
+++ b/phpunit.xml
@@ -13,6 +13,7 @@
     <server name="APP_AUTO_LANG_PUBLIC" value="true"/>
     <server name="APP_URL" value="http://bookstack.dev"/>
     <server name="ALLOWED_IFRAME_HOSTS" value=""/>
+    <server name="ALLOWED_IFRAME_SOURCES" value="https://*.draw.io https://*.youtube.com https://*.youtube-nocookie.com https://*.vimeo.com"/>
     <server name="ALLOWED_SSR_HOSTS" value="*"/>
     <server name="CACHE_DRIVER" value="array"/>
     <server name="SESSION_DRIVER" value="array"/>