Add a basic fuzz-harness

[nathaniel-brough]

Adds a basic fuzz testing harness.

Ref: #2793

[Enselic]

Interesting. I skimmed it over a bit. In (not unsafe) Rust, buffer overflows and null pointer dereferences can not happen, but it can still be useful to fuzz, I think.

Just curios: Did the fuzzer find any bugs yet?

[nathaniel-brough]

Just curios: Did the fuzzer find any bugs yet?

Sort of... I found a lot of different ways to crash bat. e.g. if the terminal/tab width in the config is really large (larger than any normal terminal width) it'll crash with an out of memory condition. I didn't think that these where "real" bugs, as they would end up being pretty unlikely, and usually down to user error. I ended up constraining the fuzzer to keep these below specific values. But it depends on your definition of a bug.

[sharkdp]

I love fuzz testing and used it extensively in another project of mine. I found quite a few interesting bugs using it.

For bat, the fact that you didn't find anything of substance (according to what you wrote above, please feel free to correct me if you think otherwise) is probably a hint that fuzz-testing is not as useful for this project. This does not mean that bat is bug free of course. But maybe it's a project that doesn't lend itself well to fuzz-testing.

In this sense: thank you very much for this experiment. But I think I'll close this without merging, in order for this not to turn into future maintenance work.