I'm sure Claude Code will happily one-shot that conversion. It's also virtually guaranteed to have messed up vital parts of the original logic in the process.
"1 or 2 plan mode prompts" to fully describe a 30-sheet complicated doc suggests a massively higher level of granularity than Opus initial plans on existing codebases give me or a less-than-expected level of Excel craziness.
And the tooling harnesses have been telling the models to add testing to things they make for months now, so why's that impressive or suprising?
I was impressed because the prompt didn't ask it to do that. It doesn't normally add tests for me without asking, YMMV.