How would you use AI to improve the testing coverage and reliability of a service?

"I applied online for a mid-level IC3 software engineering role in Apple's hardware org, and a recruiter reached out after the team liked my resume. After a short recruiter chat, I got a 24-hour Python take-home, then a 45-minute technical screen where I walked through the project and solved a palindrome-style coding question. The final loop was remote and split over two days, with six interviews total: a friendly hiring manager chat, a loose AI/system design round, and four Python rounds covering coding, class design, and debugging. Most of the interviewers were nice and the questions felt fair, but the debugging round was the hardest for me and the very last round felt much more like getting grilled. I got the rejection the following Monday, and they would not give any final-round feedback."