use std::collections::HashSet;

#[macro_use]
extern crate compare_by_address_derive;

#[derive(CompareByAddress)]
struct Empty {}

#[test]
pub fn two_references_are_equal() {
    let mut set = HashSet::new();

    let one = &Empty {};
    let still_one = &one;
    let really_still_one = &still_one;

    set.insert(one);
    set.insert(still_one);
    set.insert(really_still_one);

    assert_eq!(1, set.len());
}

#[test]
pub fn two_identical_instances_are_not_equal() {
    let mut set = HashSet::new();

    // Don't do the following.
    // I'm not sure why yet (perhaps the optimizer?), but
    // only a single Empty {} will be created and thus the addresses
    // will in fact be identical.
    // let one = &Empty {};
    // let two = &Empty {};

    let a = Empty {};
    let b = Empty {};
    let one = &a;
    let two = &b;

    set.insert(one);
    set.insert(two);

    assert_eq!(2, set.len());
}