You wil find many, many opinions on washing among the members of the board. Some do, some don't. Testing for color fastness sounds like a good idea to me.
Personally, I tend to not wash except for swaps. I'm always too excited to start the project to worry about washing. Color catchers work wonders when fabrics bleed. I did a black, white and bright pinwheel quilt with no washing and no problems.
I've never used batiks but I'm sure many experts on here that have used them will give you some info.