Fix mean on empty arrays

[Rubilmax]

Motivation

The gas report of my test suite is panicking when providing FOUNDRY_FUZZ_RUNS=0, because it's computing the mean of an empty array (&func.calls)

Solution

Check if the array is empty in calc::mean

• Closes Mean is panicking on empty arrays #2611

[onbjerg]

lgtm 😄 let's add a small test to ensure we don't break it?

also welcome to github, thanks for submitting your first pr ever to foundry 🥳

[mattsse]

thanks,

smol style nit

[mattsse]

I'd prefer

if values.is_empty() {
  return U256::zero()
}

here

[Rubilmax]

lgtm 😄 let's add a small test to ensure we don't break it?

also welcome to github, thanks for submitting your first pr ever to foundry 🥳

Ahah, I'm learning Rust
Currently it seems there are no tests for calc (or I can't find them?)
It may take me a while before adding such a test, but I may succeed

[onbjerg]

@Rubilmax the tests are in the test module in the file itself at the bottom:

foundry/common/src/calc.rs

Lines 38 to 64 in 50d73f7

	#[cfg(test)]
	mod tests {
	use super::*;
	#[test]
	fn calc_mean() {
	let values = [0u64, 1u64, 2u64, 3u64, 4u64, 5u64, 6u64];
	let m = mean(&values);
	assert_eq!(m, 3u64.into());
	}
	#[test]
	fn calc_median() {
	let mut values = vec![29, 30, 31, 40, 59, 61, 71];
	values.sort();
	let m = median_sorted(&values);
	assert_eq!(m, 40);
	}
	#[test]
	fn calc_median_even() {
	let mut values = vec![80, 90, 30, 40, 50, 60, 10, 20];
	values.sort();
	let m = median_sorted(&values);
	assert_eq!(m, 45);
	}
	}

The #[cfg(test)] attribute means that the module is only compiled during tests - the #[test] attribute on each function in there marks the function as a test 😄 Let me know if you need some help building the test

More in the Rust book: https://doc.rust-lang.org/book/ch11-01-writing-tests.html

Edit: You can basically just copy one of the tests and pass in an empty array

[Rubilmax]

@Rubilmax the tests are in the test module in the file itself at the bottom:

foundry/common/src/calc.rs

Lines 38 to 64 in 50d73f7

	#[cfg(test)]
	mod tests {
	use super::*;
	#[test]
	fn calc_mean() {
	let values = [0u64, 1u64, 2u64, 3u64, 4u64, 5u64, 6u64];
	let m = mean(&values);
	assert_eq!(m, 3u64.into());
	}
	#[test]
	fn calc_median() {
	let mut values = vec![29, 30, 31, 40, 59, 61, 71];
	values.sort();
	let m = median_sorted(&values);
	assert_eq!(m, 40);
	}
	#[test]
	fn calc_median_even() {
	let mut values = vec![80, 90, 30, 40, 50, 60, 10, 20];
	values.sort();
	let m = median_sorted(&values);
	assert_eq!(m, 45);
	}
	}

The #[cfg(test)] attribute means that the module is only compiled during tests - the #[test] attribute on each function in there marks the function as a test 😄 Let me know if you need some help building the test

More in the Rust book: https://doc.rust-lang.org/book/ch11-01-writing-tests.html

Edit: You can basically just copy one of the tests and pass in an empty array

Thank you, done!