I concede that being able to handle segfaults as test failure is a very nice feature, however dealing with signal handlers is a bit more involved that simply us

I concede that being able to handle segfaults as test failure is a very nice feature, however dealing with signal handlers is a bit more involved that simply using return values and I believe that it might cause portability issues (does it work on Windows for instance?). I agree that for a decent test framework it might be the best approach but I think at this point we're no longer talking about "a minimal unit testing framework" which was the point of TFA.