Please watch my screen recording, as it is easier to see what I am talking about rather than me trying to type all of the details: https://youtu.be/nUp7gy7tIiY
Basically, a multifaceted shortcoming...
When setting up an A/B Campaign from which to send a TEST email, why is it required that you complete ALL of the campaign information in order to send a TEST email? (By comparison, Send At information is not required when sending a TEST email from a regular campaign; why is it required when sending a TEST email from an A/B Campaign?)
I didn't realize that filling out the Size%, Send At, or the Winning Criteria fields are required in order to send a TEST email. And depending on which of these fields you leave blank, you might not get any on-screen indication that you've missed something required and as a result, your TEST emails will not send. If you watch my screen recording video, you'll see exactly what I am talking about.
MUST RE-ADD LISTS TO CAMPAIGN SETUP AFTER SENDING TEST EMAIL
Screen 1 in the A/B Campaign setup process is the Campaign Name, List(s), Segments, Suppressions, Campaign Tags, etc. But after you send a TEST email, the Lists are all stripped out and you have to re-add them to the campaign again. (Additional steps.) The rest of the campaign information from screen 1 is still present; only the Lists are stripped out, save for the "test list" you just sent a TEST email to. Why are the Lists stripped out (and nothing else is)?
CAMPAIGN NOT SAVED AFTER SENDING TEST EMAIL
I realized through some troubleshooting that after you send a TEST email from an A/B Campaign, and it "redirects" you back to screen 1 of the setup process, the A/B Campaign is not actually saved at that point, so you won't find it in the Campaigns index page. The suggestion from MP chat support was to click Save as Draft BEFORE you send the TEST email. But that is not a sound solution, because that adds several unnecessary steps/clicks to navigate back to your Campaign setup again. (Additional steps.)
****Also, in my video, I mention that Campaign Tags were being appended to A/B Campaign TEST emails, but I exported a new Custom Report based on the Campaign Tag that was used in campaign setup, and I've verified that is no longer happening, so please disregard that part. Thank you.