diff --git a/url_parser_trait/src/lib.rs b/url_parser_trait/src/lib.rs
index 399416c..d57cf00 100644
--- a/url_parser_trait/src/lib.rs
+++ b/url_parser_trait/src/lib.rs
@@ -25,12 +25,13 @@ pub trait QueryParams {
 mod tests {
     use super::*;
 
-    struct Param {
+
+    struct Param1 {
         user_id: u8,
         user_name: String,
     }
 
-    impl QueryParams for Param {
+    impl QueryParams for Param1 {
         fn get_items_as_string_map(&self) -> HashMap<String, String> {
             let mut map: HashMap<String, String> = HashMap::new();
             map.insert("user_id".to_string(), self.user_id.to_string());
@@ -39,10 +40,31 @@ mod tests {
         }
     }
 
+
+    struct Param2 {
+        user_id: u8,
+    }
+
+    impl QueryParams for Param2 {
+        fn get_items_as_string_map(&self) -> HashMap<String, String> {
+            let mut map: HashMap<String, String> = HashMap::new();
+            map.insert("user_id".to_string(), self.user_id.to_string());
+            map
+        }
+    }
+
+
     #[test]
     fn check_query() {
-        let param: Param = Param {user_id: 1, user_name: "Awayume".to_string()};
+        let param: Param1 = Param1 {user_id: 1, user_name: "Awayume".to_string()};
         let query: &str = &param.to_query_params();
         assert!(query == "?user_id=1&user_name=Awayume" || query == "?user_name=Awayume&user_id=1", "Invalid query: {}", query);
     }
+
+    #[test]
+    fn check_1key_query() {
+        let param: Param2 = Param2 {user_id: 1};
+        let query: &str = &param.to_query_params();
+        assert!(query == "?user_id=1", "Invalid query: {}", query);
+    }
 }