Having to take the states tests almost never hold up in court because the do not just test academics, they also test social non-Christian ethics that home schoolers will never answer the way the testers want. Then they put requirements at some later time tied to passing the state test ( the child can not be home schooled unless he passes the test even though not all public or private school children pass not to mention that many are being home schooled because they were not passing in the public schools).
It comes down to who owns the child the parents or the state. Who has the say in the way they are taught and raised. How much interference are you willing to allow the state in raising your child? When is enough enough? Many have not really thought through how many parental rights they have given away to the state when they send a child to public schools....Physical at the beginning of the year, forced immunizations, compliance to state standards and testing that effects greatly the outcome of life opportunities whether or not child learning style is compatible with this type of schooling, once at the school child can be questioned without your permission by social services about your family if questions not pleasing to family services child can be taken. The list goes on and on, there are books that do a better job of laying it all out than I have.