State machine design: transitioning before effect? about statemachine

[ursusursus]

Ok I have looked at the way you guys use it in Scarlet

https://github.com/Tinder/Scarlet/blob/5457f827884269a7e1a7c1c60d057d0ed5fa26b1/scarlet/src/main/java/com/tinder/scarlet/internal/connection/Connection.kt

So, you are baking the statemachine inside StateManager, which then you can run those sideffects before transitions, great

However, this messes up testing, as you can only test StateManager, and statemachine become implmentation details, which is maybe okay

But you lose ability to set initialState, unless you pass it in via StateManager ctor, which is bad, since youre leaking your implementation detail to call sites

So...I'd like your guidance on this please