Sync testing exmaple with guide.

examples/testing/src/main.rs

@@ -16,6 +16,7 @@ fn main() {
 mod test {
     use super::rocket;
     use rocket::testing::MockRequest;
+    use rocket::http::Status;
     use rocket::http::Method::*;
 
     #[test]
@@ -23,6 +24,7 @@ mod test {
         let rocket = rocket::ignite().mount("/", routes![super::hello]);
         let mut req = MockRequest::new(Get, "/");
         let mut response = req.dispatch_with(&rocket);
+        assert_eq!(response.status(), Status::Ok);
 
         let body_string = response.body().and_then(|b| b.into_string());
         assert_eq!(body_string, Some("Hello, world!".to_string()));