2 files changed, 36 insertions, 0 deletions

diff --git a/src/doc.rs b/src/doc.rs
index b7b1eacd..5f62506a 100644
--- a/src/doc.rs
+++ b/src/doc.rs
@@ -591,6 +591,12 @@ impl Region {
     }
 }
 
+impl PartialEq<&str> for Region {
+    fn eq(&self, other: &&str) -> bool {
+        self.as_str() == *other
+    }
+}
+
 impl FromStr for Region {
     type Err = &'static str;
 
@@ -688,3 +694,23 @@ cast_to_value! {
         "y" => Value::Length(v.point.y.into()),
     })
 }
+
+#[cfg(test)]
+mod tests {
+    use crate::{doc::Region, util::option_eq};
+
+    #[test]
+    fn test_partialeq_str() {
+        let region = Region([b'U', b'S']);
+        assert_eq!(region, "US");
+        assert_ne!(region, "AB");
+    }
+
+    #[test]
+    fn test_region_option_eq() {
+        let region = Some(Region([b'U', b'S']));
+
+        assert!(option_eq(region, "US"));
+        assert!(!option_eq(region, "AB"));
+    }
+}
diff --git a/src/util/mod.rs b/src/util/mod.rs
index 592ba1fa..83ec5961 100644
--- a/src/util/mod.rs
+++ b/src/util/mod.rs
@@ -226,3 +226,13 @@ pub fn pretty_array_like(parts: &[impl AsRef<str>], trailing_comma: bool) -> Str
     buf.push(')');
     buf
 }
+
+/// Check if the [`Option`]-wrapped L is same to R.
+///
+/// This is the stable version of [`Option::contains`].
+pub fn option_eq<L, R>(left: Option<L>, other: R) -> bool
+where
+    L: PartialEq<R>,
+{
+    left.map(|v| v == other).unwrap_or(false)
+}