Co-author here. 1. It's PART OF the assessment. There's also a ton of human review. But humans aren't tops at checking for correctness. Using automation helps

Co-author here. 1. It's PART OF the assessment. There's also a ton of human review. But humans aren't tops at checking for correctness. Using automation helps us run against a large set of tests, both normal and corner cases, and helps us figure out when things have gone wrong. Can even help the human find things they may have missed and need to re-review. 2. Also, some systems, like many MOOCs, use largely or only automated methods for "scalability" reasons. I don't defend this practice, but it's the reality. Our view is that those who are doing that need to be even more careful about making sure their practices make sense. 3. > It can also be done the other way around: run code that produces various bad results to exercise the student's test cases. Which is something the article is actually about (eye roll). Sometimes helps to read beyond the first sentence.