I'm a testing Coordinator at a public Middle School in the metro area and I'm going to tell you a secret. Students aren't tested heavily in Colorado.

The PARCC exams are state mandated for grades 3-10 and require three sixty minute sessions each. They are over a month long testing window. Most schools spread them over a week. The only other state mandated exam are for students designated as English Language Learners (They take an six part that takes about two hours total). Students in 11th grade also take the SAT. 

That means that most students are only in mandated testing six hours a YEAR. 

Any other acronym exam they take, STAR (for math) or SRI (for reading), are 15 minute, non-mandated, placement tests that help teachers drive instruction and aren't something kids can "opt-out" of just like a kid can't opt out of his US History midterm. 

But hey, the same people complaining about testing want high stakes accountability for kids... you can't have your cake and eat it too.