#[test]
pub fn test_distance() {


    let a = [0u8,2,3];
    let p1 = &a[0];
    let p2 = &a[2];
    assert_eq!(x::distance(p1, p2), 2);
    assert_eq!(x::distance(p2, p1), 2);
    assert_eq!(x::distance(p1, p1), 0);
}