For those of you who have Google for Domains (administrators panel), could you see and confirm if you get the following in each user address/nickname?

someoneexample.com.test-google-a.com

anyone know what the ".test-google-a.com" means?

even after creating and activating a new email address, the "test-google-a.com" still appears next to the name.

Doesn't seem to be working, Mr. Mail Delivery Subsystem sent my email back. Any screen shot?

I can confirm this. It's just a temporary option you can use to test the system before your domain is fully migrated.