use std::convert::TryInto;
use std::hash::{Hash, Hasher};
+#[cfg(test)]
+mod tests;
+
#[derive(Eq, PartialEq, Ord, PartialOrd, Debug, Clone, Copy)]
#[repr(C)]
pub struct Fingerprint(u64, u64);
let c = a.wrapping_add(b);
- Fingerprint((c >> 64) as u64, c as u64)
+ Fingerprint(c as u64, (c >> 64) as u64)
}
pub fn to_hex(&self) -> String {
--- /dev/null
+use super::*;
+
+// Check that `combine_commutative` is order independent.
+#[test]
+fn combine_commutative_is_order_independent() {
+ let a = Fingerprint::new(0xf6622fb349898b06, 0x70be9377b2f9c610);
+ let b = Fingerprint::new(0xa9562bf5a2a5303c, 0x67d9b6c82034f13d);
+ let c = Fingerprint::new(0x0d013a27811dbbc3, 0x9a3f7b3d9142ec43);
+ let permutations = [(a, b, c), (a, c, b), (b, a, c), (b, c, a), (c, a, b), (c, b, a)];
+ let f = a.combine_commutative(b).combine_commutative(c);
+ for p in &permutations {
+ assert_eq!(f, p.0.combine_commutative(p.1).combine_commutative(p.2));
+ }
+}