A terminal UI you can write a test against

DiskPush's two-pane browser was 940 lines of hand-rolled ANSI. Rewriting it on HQTUI made the frame a value, and three bugs fell out that reading the code had missed.

Read the original (By Anthony Ettinger, via Chovy's Blog): https://dev.profullstack.com/~anthony/blog/084-post.html