chore: small changes

lib/game/components/game_flow_controller.dart

@@ -19,21 +19,21 @@ class GameFlowController extends ComponentController<PinballGame>
   @override
   void onNewState(GameState state) {
     if (state.isGameOver) {
-      initialsInput();
+      _initialsInput();
     } else {
       start();
     }
   }
 
   /// Puts the game in the initials input state.
-  void initialsInput() {
+  void _initialsInput() {
     // TODO(erickzanardo): implement score submission and "navigate" to the
     // next page
     component.descendants().whereType<Backbox>().first.initialsInput(
           score: state?.score ?? 0,
           characterIconPath: component.characterTheme.leaderboardIcon.keyName,
         );
-    component.firstChild<CameraController>()?.focusOnGameOverBackbox();
+    component.firstChild<CameraController>()!.focusOnGameOverBackbox();
   }
 
   /// Puts the game in the playing state.

test/game/components/backbox/backbox_test.dart

@@ -61,25 +61,22 @@ void main() {
       },
     );
 
-    group('renders correctly', () {
     flameTester.testGameWidget(
-        'empty',
+      'renders correctly',
       setUp: (game, tester) async {
         await game.images.loadAll(assets);
         game.camera.zoom = 6;
         game.camera.followVector2(Vector2(0, -130));
         await game.ensureAdd(Backbox());
-          await game.ready();
         await tester.pump();
       },
       verify: (game, tester) async {
         await expectLater(
           find.byGame<EmptyPinballTestGame>(),
-            matchesGoldenFile('../golden/backbox/empty.png'),
+          matchesGoldenFile('../golden/backbox.png'),
         );
       },
     );
-    });
 
     flameTester.test(
       'initialsInput adds InitialsInputDisplay',