feat: made RoundBumper use InitialPosition

lib/game/components/round_bumper.dart

@@ -4,19 +4,14 @@ import 'package:pinball/game/game.dart';
 /// {@template round_bumper}
 /// Circular body that repels a [Ball] on contact, increasing the score.
 /// {@endtemplate}
-class RoundBumper extends BodyComponent with ScorePoints {
+class RoundBumper extends BodyComponent with ScorePoints, InitialPosition {
   /// {@macro round_bumper}
   RoundBumper({
-    required Vector2 position,
     required double radius,
     required int points,
-  })  : _position = position,
+  })  : _radius = radius,
-        _radius = radius,
         _points = points;
 
-  /// The position of the [RoundBumper] body.
-  final Vector2 _position;
-
   /// The radius of the [RoundBumper].
   final double _radius;
 
@@ -33,7 +28,7 @@ class RoundBumper extends BodyComponent with ScorePoints {
     final fixtureDef = FixtureDef(shape)..restitution = 1;
 
     final bodyDef = BodyDef()
-      ..position = _position
+      ..position = initialPosition
       ..type = BodyType.static;
 
     return world.createBody(bodyDef)..createFixture(fixtureDef);

test/game/components/round_bumper_test.dart

@@ -18,10 +18,9 @@ void main() {
       (game) async {
         await game.ready();
         final roundBumper = RoundBumper(
-          position: Vector2.zero(),
           radius: radius,
           points: points,
-        );
+        )..initialPosition = Vector2.zero();
         await game.ensureAdd(roundBumper);
 
         expect(game.contains(roundBumper), isTrue);
@@ -32,10 +31,9 @@ void main() {
       'has points',
       (game) async {
         final roundBumper = RoundBumper(
-          position: Vector2.zero(),
           radius: radius,
           points: points,
-        );
+        )..initialPosition = Vector2.zero();
         await game.ensureAdd(roundBumper);
 
         expect(roundBumper.points, equals(points));
@@ -48,10 +46,9 @@ void main() {
         (game) async {
           final position = Vector2.all(10);
           final roundBumper = RoundBumper(
-            position: position,
             radius: radius,
             points: points,
-          );
+          )..initialPosition = position;
           await game.ensureAdd(roundBumper);
           game.contains(roundBumper);
 
@@ -63,10 +60,9 @@ void main() {
         'is static',
         (game) async {
           final roundBumper = RoundBumper(
-            position: Vector2.zero(),
             radius: radius,
             points: points,
-          );
+          )..initialPosition = Vector2.zero();
           await game.ensureAdd(roundBumper);
 
           expect(roundBumper.body.bodyType, equals(BodyType.static));
@@ -79,10 +75,9 @@ void main() {
         'exists',
         (game) async {
           final roundBumper = RoundBumper(
-            position: Vector2.zero(),
             radius: radius,
             points: points,
-          );
+          )..initialPosition = Vector2.zero();
           await game.ensureAdd(roundBumper);
 
           expect(roundBumper.body.fixtures[0], isA<Fixture>());
@@ -93,10 +88,9 @@ void main() {
         'has restitution',
         (game) async {
           final roundBumper = RoundBumper(
-            position: Vector2.zero(),
             radius: radius,
             points: points,
-          );
+          )..initialPosition = Vector2.zero();
           await game.ensureAdd(roundBumper);
 
           final fixture = roundBumper.body.fixtures[0];
@@ -108,10 +102,9 @@ void main() {
         'shape is circular',
         (game) async {
           final roundBumper = RoundBumper(
-            position: Vector2.zero(),
             radius: radius,
             points: points,
-          );
+          )..initialPosition = Vector2.zero();
           await game.ensureAdd(roundBumper);
 
           final fixture = roundBumper.body.fixtures[0];