diff --git a/src/lib.rs b/src/lib.rs
index 387f566..1795a02 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -185,7 +185,7 @@ impl Unquote for String {
 
 #[cfg(test)]
 mod test {
-    use crate::{from_base36, ToBase36, optional_data_line, mock, segments_from_string, Quote, Unquote};
+    use crate::{from_base36, ToBase36, optional_data_line, mock, segments_from_string, Quote, Unquote, new_unique_id};
 
     #[test]
     fn test_from_base36() {
@@ -234,4 +234,11 @@ mod test {
         let expected = "who the fuck is scraeming \"LOG OFF\" at my house.\nshow yourself, coward.\ni will never log off".to_string();
         assert_eq!(output, expected);
     }
+
+    #[test]
+    fn test_new_unique_id() {
+        assert_eq!(new_unique_id(vec!["0".to_string(), "2".to_string()]), "1".to_string());
+        assert_eq!(new_unique_id(vec!["0".to_string(), "1".to_string()]), "2".to_string());
+        assert_eq!(new_unique_id(vec!["1".to_string(), "z".to_string()]), "0".to_string());
+    }
 }