I'd imagine that it begins well before that with Requirements Management: probably more important than any other single thing since that drives the entire development process.

Anyway, I'm sure there used to be a blog for the Dreamliner test team, but I can't find it now, so here's this instead: https://www.wired.com/2010/03/a-look-inside-the-brains-of-bo...

And specifically for code, look here: https://ldra.com/aerospace-defence/standards/misra-cc/

and (JSF, not commercial) https://www.f35.com/about/life-cycle/software