mod tests {
    use super::*;

    #[test]
    fn compact_ipv6_ranges_preserve_numeric_order() {
        assert_eq!(std::mem::size_of::<V6Range>(), 34);
        assert_eq!(std::mem::size_of::<V4Range>(), 12);
        let ranges = [
            V6Range {
                start: 0u128.to_be_bytes(),
                end: 127u128.to_be_bytes(),
                country: *b"PL",
            },
            V6Range {
                start: 256u128.to_be_bytes(),
                end: 65535u128.to_be_bytes(),
                country: *b"DE",
            },
            V6Range {
                start: (1u128 << 120).to_be_bytes(),
                end: u128::MAX.to_be_bytes(),
                country: *b"US",
            },
        ];
        for (address, expected) in [
            (0, Some(*b"PL")),
            (127, Some(*b"PL")),
            (128, None),
            (255, None),
            (256, Some(*b"DE")),
            (65535, Some(*b"DE")),
            (65536, None),
            (1u128 << 120, Some(*b"US")),
            (u128::MAX, Some(*b"US")),
        ] {
            assert_eq!(find_v6(&ranges, address.to_be_bytes()), expected);
        }
    }

    #[test]
    fn range_lookup_handles_gaps() {
        let directory = tempfile::tempdir().unwrap();
        std::fs::write(
            directory.path().join("user-country-ipv4.csv"),
            "192.0.2.0,192.0.2.255,PL\n",
        )
        .unwrap();
        std::fs::write(
            directory.path().join("user-country-ipv6.csv"),
            "2001:db8::,2001:db8::ffff,PL\n",
        )
        .unwrap();
        let db = Database::load_format(directory.path(), DatabaseFormat::CsvPair).unwrap();
        assert_eq!(
            db.country("192.0.2.7".parse().unwrap()).as_deref(),
            Some("PL")
        );
        assert!(db.country("198.51.100.1".parse().unwrap()).is_none());
    }
}