I'm cutting out docker for the time being just to have one variable at a time solving the deployment issue. It works fine on localhost, but seems to be a different story on heroku for spring and kotlin

What is exactly your problem with mocking?

I'm not focused on that particular issue at the moment, but when I was last trying to work with it, I was having a really tough time with setting up the proper configurations for springboottesting in mockito (i.e. automatic configuration set to my App::class.java

expected Array<KClass> but found Class<App>

)

And with Docker? Usually generating a fatjar from a multistage gradle -> openjdk-alpine does nicely for Ktor and Vert.x that I've tried it on...

That, I'm actually about to post in main

Both Ktor and Vert.x have instructions for making a fatjar, spring doesn't?

Spring does yeah