Add tests for search option.

src/types/object.rs

@@ -80,6 +80,7 @@ pub struct RegularLink<'s> {
     pub link_type: LinkType<'s>,
     pub path: &'s str,
     pub raw_link: &'s str,
+    pub search_option: Option<&'s str>,
 }
 
 #[derive(Debug, PartialEq)]