diff --git a/tests/image_prep/_user_accounts.yml b/tests/image_prep/_user_accounts.yml
index d099091a..10834efc 100644
--- a/tests/image_prep/_user_accounts.yml
+++ b/tests/image_prep/_user_accounts.yml
@@ -161,6 +161,7 @@
           Defaults>mitogen__require_tty requiretty
           Defaults>mitogen__require_tty_pw_required requiretty,targetpw
         prepend_newline: true
+        validate: '/usr/sbin/visudo -cf %s'
 
     - name: Configure sudoers users
       blockinfile: