Re: Half sibling pressuring me for DNA test??

I don't know about the costs of DNA testing, but there are many sources available out there, these days.

As far as interacting with the sister, if you aren't concerned about the uncle's Will (good for you!), then there is literally no reason (legal, or otherwise) to communicate with her.  Seriously.  And, if you choose this route, it means not answering her calls, responding to emails, blocking her texts, etc.  If she's toxic to you, there are the options of:  a) exposing yourself to manipulations or other toxic behaviors by allowing communications, or; b) going "No Contact" and disallow her drama/trauma.  It's a personal decision, and you know better than anyone else whether this line of communication is healthy, or not.