#[derive(Eq, PartialEq, Debug, Clone, Serialize, Deserialize)]
pub struct Position(pub u64, pub u64);
#[test]
fn deserialize_ok() {
use serde_json;
let s = r#"[12, 1]"#;
let deserialized: Result<Position, _> = serde_json::from_str(s);
assert_eq!(deserialized.unwrap(), Position(12, 1));
}