refactor: use extension for initial pinball game

lib/game/pinball_game.dart

@@ -8,13 +8,6 @@ import 'package:pinball_theme/pinball_theme.dart';
 class PinballGame extends Forge2DGame with FlameBloc {
   PinballGame({required this.theme});
 
-  PinballGame.initial()
-      : this(
-          theme: const PinballTheme(
-            characterTheme: DashTheme(),
-          ),
-        );
-
   final PinballTheme theme;
 
   void spawnBall() {

test/game/components/anchor_test.dart

@@ -5,11 +5,13 @@ import 'package:flame_test/flame_test.dart';
 import 'package:flutter_test/flutter_test.dart';
 import 'package:pinball/game/game.dart';
 
+import '../../helpers/helpers.dart';
+
 void main() {
   TestWidgetsFlutterBinding.ensureInitialized();
 
   group('Anchor', () {
-    final flameTester = FlameTester(PinballGame.initial);
+    final flameTester = FlameTester(PinballGameX.initial);
 
     flameTester.test(
       'loads correctly',

test/game/components/ball_test.dart

@@ -13,7 +13,7 @@ void main() {
   TestWidgetsFlutterBinding.ensureInitialized();
 
   group('Ball', () {
-    final flameTester = FlameTester(PinballGame.initial);
+    final flameTester = FlameTester(PinballGameX.initial);
 
     flameTester.test(
       'loads correctly',

test/game/components/plunger_test.dart

@@ -10,7 +10,7 @@ import '../../helpers/helpers.dart';
 
 void main() {
   TestWidgetsFlutterBinding.ensureInitialized();
-  final flameTester = FlameTester(PinballGame.initial);
+  final flameTester = FlameTester(PinballGameX.initial);
 
   group('Plunger', () {
     flameTester.test(

test/game/components/wall_test.dart

@@ -32,7 +32,7 @@ void main() {
         },
       );
     });
-    final flameTester = FlameTester(PinballGame.initial);
+    final flameTester = FlameTester(PinballGameX.initial);
 
     flameTester.test(
       'loads correctly',

test/game/pinball_game_test.dart

@@ -1,8 +1,4 @@
-import 'package:bloc_test/bloc_test.dart';
 import 'package:flutter_test/flutter_test.dart';
-import 'package:pinball/game/game.dart';
-
-import '../helpers/helpers.dart';
 
 void main() {
   group('PinballGame', () {
@@ -10,23 +6,4 @@ void main() {
     // [BallScorePointsCallback] once the following issue is resolved:
     // https://github.com/flame-engine/flame/issues/1416
   });
-
-  group('PinballGame.initial', () {
-    final gameBloc = MockGameBloc();
-
-    setUp(() {
-      whenListen(
-        gameBloc,
-        const Stream<GameState>.empty(),
-        initialState: const GameState.initial(),
-      );
-    });
-
-    flameBlocTester(gameBloc: gameBloc).test(
-      'has initial theme',
-      (game) async {
-        expect(game.theme, PinballGame.initial().theme);
-      },
-    );
-  });
 }

test/helpers/builders.dart

@@ -1,12 +1,13 @@
 import 'package:flame_test/flame_test.dart';
 import 'package:flutter_bloc/flutter_bloc.dart';
 import 'package:pinball/game/game.dart';
+import 'package:pinball_theme/pinball_theme.dart';
 
 FlameTester<PinballGame> flameBlocTester({
   required GameBloc gameBloc,
 }) {
   return FlameTester<PinballGame>(
-    PinballGame.initial,
+    PinballGameX.initial,
     pumpWidget: (gameWidget, tester) async {
       await tester.pumpWidget(
         BlocProvider.value(
@@ -17,3 +18,11 @@ FlameTester<PinballGame> flameBlocTester({
     },
   );
 }
+
+extension PinballGameX on PinballGame {
+  static PinballGame initial() => PinballGame(
+        theme: const PinballTheme(
+          characterTheme: DashTheme(),
+        ),
+      );
+}