There is only one test... Look in the mirror and be honest about yourself...
It's very hard, and it can be quite wrenching, so sadly many people ask the internet by answering ridiculous survey questions(just think about that for a second).....why not just ask a psychic?
Also to the OP... I would urge you to consider that being gender fluid is not about being stuck in the middle gender wise...I've learned over the years that lots of people are quite comfortable with an identity that is gender fluid...so it's not really being stuck..if you can be happy with your gender identity that's a very simple and constructive thing
Unfortunately for gender fluid people, the world is almost exclusively binary gendered..... It creates a situation where people that don't live as one gender usually end up being outsiders and being marginalized by society...and so gender fluid learn how to cope in that world and can feel stuck as an outsider..