use std::{env, num::NonZeroUsize};
pub fn get_concurrency() -> usize {
if let Ok(value) = env::var("RUST_TEST_THREADS") {
match value.parse::<NonZeroUsize>().ok() {
Some(n) => n.get(),
_ => panic!("RUST_TEST_THREADS is `{}`, should be a positive integer.", value),
}
} else {
num_cpus::get_physical()
}
}