Quicksort algorithm implemented on rust

quick_sort.rs

pub fn quick_sort<T: Clone + PartialOrd>(arr: &[T]) -> Vec<T> {
    if arr.len() <= 1 {
        return arr.to_vec();
    }

    if arr.len() == 2 {
        let a = arr[0].clone();
        let b = arr[1].clone();

        return if a < b { vec![a, b] } else { vec![b, a] };
    }

    let pivot = arr.get(0).cloned().unwrap();

    let mut less = Vec::default();
    let mut greater = Vec::default();

    for a in arr.into_iter().skip(1).map(|a| a.to_owned()) {
        if a < pivot {
            less.push(a);
        } else {
            greater.push(a);
        }
    }

    [quick_sort(&less), vec![pivot], quick_sort(&greater)].concat()
}

#[cfg(test)]
mod tests {
    use super::*;

    #[test]
    fn it_case_0() {
        let result = quick_sort::<i32>(&[]);
        assert_eq!(result, &[]);
    }

    #[test]
    fn it_case_1() {
        let result = quick_sort(&[3]);
        assert_eq!(result, vec![3]);
    }

    #[test]
    fn it_case_2() {
        let result = quick_sort(&[5, 3]);
        assert_eq!(result, vec![3, 5]);
    }

    #[test]
    fn it_case_n() {
        let result = quick_sort(&[20, 5, 4, 10, 16, 2, 3]);
        assert_eq!(result, vec![2, 3, 4, 5, 10, 16, 20]);
    }

    #[test]
    fn it_case_negative() {
        let result = quick_sort(&[5, 4, -10, -16, 2, 3, 0]);
        assert_eq!(result, vec![-16, -10, 0, 2, 3, 4, 5]);
    }
}

more faster solution is here https://gist.github.com/misha-krainik/ed223cef8dca208c2c558c0a43220bef