So turns out my manager wants me to do QA automation (not in Espresso btw) of my own items "because we're all in the same team". The weirdest thing is that she's obsessed with "best practices" about daily iteration work such as not starting to work on something until test planning is done (she gets CRAYZEEE about that). Violating one of the core development principles is out the window so I guess the question is am I in a good place to ask for a raise since I'm going to have dual roles?

This is just my personal opinion. But I would first do the QA and then ask for the raise based on how much work it actually is and on the evidence, that it's taking me more time and that they actually now need me more if I have two roles

Asking for the raise prematurely is in my own personal opinion unreasonable. If you don't agree with the manager, you should complain to the manager or to someone higher instead of being passive aggressive about it with "ok, but I want more money then". I think the only thing that's going to achieve is make the manager hate you and you'll still end up doing it... But then again I don't really know the work dynamic at your company so do whatever seams *smartest*

I was definitely not going to ask it before accomplishing anything, but that's a good point you make anyway.