Testify means lot's of things. It can be said almost in any situation. Nancy Grace is a fan of Testification. Testifying can mean you're trying to receive some justice (see receiving justice for more info). You're hitting on someone. You're trying to get laid. You're trying to tell someone what the fuck is up. You're trying to get belligerent drunk. You're trying this, trying that. Ect.
Person 1: Did you see Robert last night? He was definitely trying to testify.