[DoofusOfDeath]

Thank you for stating this so succinctly!

This concern has been nagging me in the back of my mind, but I hadn't convinced myself that code-coverage was insufficient (in practice) until you framed it this way.

Now all kinds of supporting examples come to mind:

- divide-by-0 errors

- floating-point exceptions

- numeric underflow / overflow (both silent and signaled)

The alternative code paths exercised by these situations are generally outside the purview of code-coverage tools, because they reside in the silicon / firmware, process' default signal handlers, etc.

[m4r35n357]

Mutation testing can expose weaknesses like these in your automated tests.