There is a facility to send a Test Email so that you can check the appearance of the Campaign on various devices to ensure it is fully responsive.
NOTE: The purpose of sending a Test Email is to be able to verify that you have not “goofed” with any content, and to see how “responsive” it is you can check on its appearance on various devices.
Sending a Test Email is not a measure of its Inboxing capability as it is just one email, not part of a bulk mailout as it will be when sent to your Subscriber List. Exactly the same applies to mailing to a List with just one or two Email Addresses in it (yours) as that is entirely unrepresentative of what happens when you mail to a List of Subscribers. The ONLY true measure of the level of success is to mailout to your List and check the Opens and Clicks (remember to set URL Tracking to “Yes”) in the Campaign Stats.