implement error handling for game

src/game.rs

@@ -2,6 +2,7 @@ use crate::{
     optional_data_line, Avatar, Dialogue, Ending, Font, Item, Palette, Room, Sprite, TextDirection,
     Tile, ToBase36, Variable,
 };
+use std::error::Error;
 
 #[derive(Debug, Eq, PartialEq)]
 pub struct Version {
@@ -39,8 +40,8 @@ pub struct Game {
     pub variables: Vec<Variable>,
 }
 
-impl From<String> for Game {
-    fn from(string: String) -> Game {
+impl Game {
+    fn from(string: String) -> Result<Game, &'static dyn Error> {
         let mut string = format!("{}\n\n", string.trim_matches('\n'));
 
         if string.starts_with("# BITSY VERSION") {
@@ -142,23 +143,25 @@ impl From<String> for Game {
         assert!(avatar.is_some());
         let avatar = avatar.unwrap();
 
-        Game {
-            name,
-            version,
-            room_format,
-            font,
-            custom_font,
-            text_direction,
-            palettes,
-            rooms,
-            tiles,
-            avatar,
-            sprites,
-            items,
-            dialogues,
-            endings,
-            variables,
-        }
+        Ok (
+            Game {
+                name,
+                version,
+                room_format,
+                font,
+                custom_font,
+                text_direction,
+                palettes,
+                rooms,
+                tiles,
+                avatar,
+                sprites,
+                items,
+                dialogues,
+                endings,
+                variables,
+            }
+        )
     }
 }
 
@@ -301,7 +304,9 @@ impl Game {
 
 #[test]
 fn test_game_from_string() {
-    let output = Game::from(include_str!["test-resources/default.bitsy"].to_string());
+    let output = Game::from(
+        include_str!["test-resources/default.bitsy"].to_string()
+    ).unwrap();
 
     let expected = crate::mock::game_default();
 
@@ -412,7 +417,7 @@ fn test_bitsy_omnibus() {
 
         println!("Testing: {}...", path.display());
         let game_data = std::fs::read_to_string(path).unwrap();
-        let game = Game::from(game_data.clone());
+        let game = Game::from(game_data.clone()).unwrap();
         assert_eq!(
             game.to_string().trim_matches('\n'),
             game_data.trim_matches('\n')
@@ -424,7 +429,10 @@ fn test_bitsy_omnibus() {
 
 #[test]
 fn test_arabic() {
-    let game = Game::from(include_str!("test-resources/arabic.bitsy").to_string());
+    let game = Game::from(
+        include_str!("test-resources/arabic.bitsy").to_string()
+    ).unwrap();
+
     assert_eq!(game.font, Font::Arabic);
     assert_eq!(game.text_direction, TextDirection::RightToLeft);
 }