Ive done this too. The exercise wasnt arrays (Im militant about only setting very realistic tasks). My task required modifying existing production-like code and tests.
My hope was always that the candidates would do TDD where it seemed simple and obvious to do so. It was actually pretty rare but the candidates that defaulted to doing that always ended up being better in my opinion. They were always made offers higher than my company could afford elsewhere (so i guess in others' opinions too).
In this thread https://news.ycombinator.com/item?id=43060636 I pondered why most people dont default to TDD for production code and the answer invariably seemed to be "we didnt think TDD was a thing you could do with integration/e2e tests".
My hope was always that the candidates would do TDD where it seemed simple and obvious to do so. It was actually pretty rare but the candidates that defaulted to doing that always ended up being better in my opinion. They were always made offers higher than my company could afford elsewhere (so i guess in others' opinions too).
In this thread https://news.ycombinator.com/item?id=43060636 I pondered why most people dont default to TDD for production code and the answer invariably seemed to be "we didnt think TDD was a thing you could do with integration/e2e tests".