replace `#[main] fn main() {}` with `#![rustest]` or similar

[rursprung]

it feels a bit weird to have to add #[main] fn main() {}. having something along the lines of #![rustest] (or #![cfg_attr(test, rustest)] for unit tests) might be cleaner to read (and maintain longer-term?).

though maybe #13 will come up with a way where this isn't needed at all in the code and can instead be controlled via Cargo.toml?

[mgautierfr]

I have reused the naming of other projects. For example, tokio uses main attribute too (https://docs.rs/tokio/latest/tokio/attr.main.html)

#![cfg_attr(test, rustest)] will apply the rustest attribute only when we have the test configuration. But the main function would still be define all the time.

With

#[cfg(test)]
#[rustest::main]
fn main() {}

the main function exists only in test cfg.

[rursprung]

but the difference is: with tokio you actually implement something in your main function. here you just add it but in reality it's being implemented by the macro.

with my suggestion you have a macro on the module level (note the !) which injects the whole fn main. since you don't want that to happen if it isn't a test i suggested using cfg_attr for that (and because rustest wouldn't be found as a non-dev dependency). though rustest as a name for the macro would probably not work since it's also the crate name and would thus colide - so maybe #![use_rustest]?

either way this isn't that important, it's mostly bike-shedding and i thought i note it down to see your opinion on it