simplify json error

src/main.rs

@@ -1,9 +1,9 @@
 use std::env;
-use serde::{Deserialize};
+use serde::{Deserialize, Serialize};
 use std::fs;
 use std::io::Write;
 
-#[derive(Deserialize)]
+#[derive(Deserialize, Serialize, Default)]
 struct SlippiPaths {
     user_json_folder_path: String,
     slippi_folder_path: String
@@ -18,7 +18,8 @@ fn main() -> std::io::Result<()> {
     let new_user_file_path = format!("{}/user.json", paths.slippi_folder_path);
     let user_json_file_path = format!("{}/{}.json", paths.user_json_folder_path, user_json_name);
 
-    let new_user_json = std::fs::read_to_string(user_json_file_path).expect(&format!("Could not load user json with name {}", user_json_name));
+    let new_user_json = std::fs::read_to_string(user_json_file_path).unwrap();
+
     create_new_file_with_contents(&new_user_file_path, &new_user_json)
 }
 
@@ -38,16 +39,19 @@ fn create_new_file_with_contents(path: &str, contents: &str) -> std::io::Result<
 }
 
 fn get_slippi_paths(json_file_path: &str) -> SlippiPaths {
-    let file_paths_json = fs::read_to_string(json_file_path).expect("filepaths.json is required and must be found in same directory that the executable is running in");
-    let expected_json_format = "{ \"user_json_folder_path\": string, \"slippi_folder_path\": string }";
-    let parsing_error_msg = format!("Could not parse from {json_file_path}. Expected format: {expected_json_format}");
+    let file_paths_json =
+        fs::read_to_string(json_file_path)
+            .expect("filepaths.json is required and must be found in same directory that the executable is running in");
+
+    let json_format = serde_json::to_string(&SlippiPaths::default()).unwrap();
+    let parsing_error_msg = format!("Could not parse json. Expected format: {json_format}");
     serde_json::from_str(&file_paths_json).expect(&parsing_error_msg)
 }
 
 fn get_user_name_from_args() -> String {
     env::args()
         .collect::<Vec<String>>()
         .get(1)
-        .expect("Command line argument containing user name is required. Ex: ./change-slippi-user my-secondary")
+        .expect("Command line argument container user is required. Ex: `$ ./change-slippi-user my-secondary`")
         .clone()
 }