It depends on the stakes mainly, but also the experience of the stakeholders of a project. Both extremes (heavily tested, proven code vs "let's hope this works"

It depends on the stakes mainly, but also the experience of the stakeholders of a project. Both extremes (heavily tested, proven code vs "let's hope this works" code) are common but usually you're not allowed to speak about anything because of non-disclosure agreements and proven or not, all code is manually tested like crazy anyway. You commonly get insane overhead and just working code.