[Question] what about adding Exception throwing while mutating

[LowLevelMahn]

... to test exception safetiness

something like on-every-line step by step during test-run

or is something like that complete out of mutation testing scope?

[AlexDenisov]

Arguably, it can be seen as out of scope, but I see the value in it.
There are no strict rules when it comes to mutation testing, but IMO MT should be changing or removing things from a program, not adding new ones.

Aside from that, the challenge with these kinds of mutations is what to insert (should it be throw 42, throw std::bad_alloc, or throw your_custom_exception?) and where. And the "where" IMO is the hardest part.

I would love to hear suggestions if you have any, otherwise I'll need to think about it a bit more.

[LowLevelMahn]

Aside from that, the challenge with these kinds of mutations is what to insert (should it be throw 42, throw std::bad_alloc, or throw your_custom_exception?) and where. And the "where" IMO is the hardest part.

where:
(as seen from the source) - wandering from line to line (so at first before first line of code, second next line after first line etc.)
or somewhere randomly

what:
i find that hard too but i like the idea having these 3 you mentioned (or pure random ones) - in the end its random enough to simulate that deep-down-under code which is not in your control is starting to use exception throwing

what-extended:
even adding more harder failes like divison by zero or nullptr-exceptions could be nice for checking the aborting behavior

I'll need to think about it a bit more.

that is what i hoped for :)