If you oppose standardized testing, taking the test is the least damaging. The rest of the school year wasted on teaching to the test is where the real damage is done. As far as the stress of taking the test goes, kids need to learn at some point. Eventually those kids either learn how to take tests or learn how to use the fryer at McDonald’s.
Don't be silly! A fryer at McDonalds?
The ONLY standardized test that my three homeschoolers took was the GRE for graduate school. One took two types standardized tests. His exams for his CPA ( Certified Public Accountant) were the second!
By the way, the two younger homeschoolers took the GRE for graduate school when they were 18, the year they graduated from college with B.S. degrees in mathematics.
If enough parents opt their kids out, any tests given will be meaningless and everyone will know it. Then with meaningless tests results the principals and teachers are then free to teach what they want.
Result: Local control and sabotaged Common Core.