We are going to run a drip campaign that contains 5 emails. We are getting requests in to A/B test the emails in this campaign. I only know of a way to manually A/B test which would defeat the purpose of an automated drip campaign. Does anyone know of a way we can test this out using emails in an engagement program?
I think it's possible to set up a Champion/Challenger A/B test in an engagement program such as the one you described.
Here's the link to the Product Docs article: Email Tests - Champion/Challenger - Marketo Docs - Product Documentation
Or, like you said, you can do more of a more manual set up using the Random Sample functionality along with building out additional email assets. Here's a screenshot for quick reference.
If you have any questions let me know!