Which thing was that?

(If you need help finding it try visiting https://tools.simonwillison.net/hn-comments-for-user and searching for simonw - you can then search my 1,000 most recent comments in one place.)

If my tests are green then it tells me a LOT about what the software is capable of, even if I haven't reviewed every line of the implementation.

The next step is to actually start using it for real problems. That should very quickly shake out any significant or minor issues that sneaked past the automated tests.

I've started thinking about this by comparing it to work I've done within larger companies. My team would make use of code written by other teams without reviewing everything those other teams had written. If their tests passed we would build against their stuff, and if their stuff turned out not to work we would let them know or help debug and fix it ourselves.