Add ParseMode serialization tests

src/core/types/parse_mode.rs

@@ -68,3 +68,25 @@ pub enum ParseMode {
     HTML,
     Markdown,
 }
+
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn html_serialization() {
+        let expected_json = String::from(r#""HTML""#);
+        let actual_json = serde_json::to_string(&ParseMode::HTML).unwrap();
+
+        assert_eq!(expected_json, actual_json)
+    }
+
+    #[test]
+    fn markdown_serialization() {
+        let expected_json = String::from(r#""Markdown""#);
+        let actual_json = serde_json::to_string(&ParseMode::Markdown).unwrap();
+
+        assert_eq!(expected_json, actual_json)
+    }
+}