When I was hs my DS, I was working on the multidisciplinary team in ps, so I had access to the tests we used at work. At the end of the year, I'd borrow a Woodcock-Johnson battery over a weekend and test him myself. Then I'd send that result in to the state, because at that time we were doing Approved Home Study. The options for that were test, portfolio, letter from a teacher certified to teach at the student's level. Test was easiest.
After I retired, I started schooling Other People's Kids, and used the Iowa, until our state adopted a version of the Iowa and I couldn't get it privately anymore. Then I finally found the Stanford 10, and a way to be recognized as a school not a homeschool, and I've used it ever since. If nobody enrolls by this fall, that will be over with, so I'll probably still use the Stanford but get it from BJU or somebody in North Carolina you can order from. (If that doesn't work out for some reason, I still have a tote full of PIAT and WRAT.) i won't be schooling anyone but my grandson(s) in that case. i do/have done it mainly so the parents of OPKs could see that their kids were actually learning while with me - so, as an accountability measure to the parents.
Although I *know* that a test is only a snapshot of a limited portion of what's been learned, it still feels good to see those scores go up year after year.