fix(enums) make enum variants more consistent

closes #1545

exercises/08_enums/enums3.rs

@@ -18,6 +18,8 @@ struct Point {
 
 struct State {
     color: (u8, u8, u8),
+    width: u8,
+    height: u8,
     position: Point,
     quit: bool,
     message: String,
@@ -36,6 +38,11 @@ impl State {
         self.message = s
     }
 
+    fn resize(&mut self, w: u8, h: u8) {
+        self.width = w;
+        self.height = h;
+    }
+
     fn move_position(&mut self, p: Point) {
         self.position = p;
     }
@@ -55,16 +62,21 @@ mod tests {
     fn test_match_message_call() {
         let mut state = State {
             quit: false,
+            width: 0,
+            height: 0,
             position: Point { x: 0, y: 0 },
             color: (0, 0, 0),
             message: "hello world".to_string(),
         };
         state.process(Message::ChangeColor(255, 0, 255));
         state.process(Message::Echo(String::from("Hello world!")));
+        state.process(Message::Resize { w: 10, h: 30 });
         state.process(Message::Move(Point { x: 10, y: 15 }));
         state.process(Message::Quit);
 
         assert_eq!(state.color, (255, 0, 255));
+        assert_eq!(state.width, 10);
+        assert_eq!(state.height, 30);
         assert_eq!(state.position.x, 10);
         assert_eq!(state.position.y, 15);
         assert_eq!(state.quit, true);