add test case for host: `http://192.168.0.257` fixes #140 <!-- Reviewable:start --> [<img src="https://reviewable.io/review_button.png" height=40 alt="Review on Reviewable"/>](https://reviewable.io/reviews/servo/rust-url/141) <!-- Reviewable:end -->
@@ -366,4 +366,5 @@ fn host() {
assert!(Host::parse("42.0x1232131").is_err());
assert_eq!(Host::parse("111").unwrap(), Host::Ipv4(Ipv4Addr::new(0, 0, 0, 111)));
assert_eq!(Host::parse("2..2.3").unwrap(), Host::Domain("2..2.3".to_owned()));
+ assert!(Host::parse("192.168.0.257").is_err());
}