I was also looking for this feature. That would help me a lot. Not only to test A/B calls, but also to set calls to different events with only one popup at a time.
We are currently creating a workaround for a pop-up CTA A/B test since A/B testing is not available in pop-ups currently. This seems like it has been a requested need for several years and I'm hoping we can get this on a road map to better test pop-ups and make data-driven decisions in the mix for clients. Can anyone @hubspot advise if this functionality has been reviewed by the team recently to determine priority, or not, for an update?