feat: implemented ScorePoints mixin

lib/game/components/ball.dart

@@ -1,8 +1,11 @@
+import 'package:flame_bloc/flame_bloc.dart';
 import 'package:flame_forge2d/body_component.dart';
 import 'package:flutter/material.dart';
 import 'package:forge2d/forge2d.dart';
+import 'package:pinball/game/game.dart';
 
-class Ball extends BodyComponent {
+class Ball extends BodyComponent<PinballGame>
+    with BlocComponent<GameBloc, GameState> {
   Ball({
     required Vector2 position,
   }) : _position = position {

lib/game/components/components.dart

@@ -1 +1,2 @@
 export 'ball.dart';
+export 'score_points.dart';

lib/game/components/score_points.dart

@@ -0,0 +1,22 @@
+// ignore_for_file: avoid_renaming_method_parameters
+
+import 'package:flame_forge2d/flame_forge2d.dart';
+import 'package:pinball/game/game.dart';
+
+mixin ScorePoints {
+  int get points;
+}
+
+class BallHasScoreCallback extends ContactCallback<Ball, ScorePoints> {
+  @override
+  void begin(
+    Ball ball,
+    ScorePoints hasPoints,
+    Contact _,
+  ) {
+    ball.gameRef.read<GameBloc>().add(Scored(points: hasPoints.points));
+  }
+
+  @override
+  void end(Ball _, ScorePoints __, Contact ___) {}
+}

test/game/components/score_points_test.dart

@@ -0,0 +1,60 @@
+import 'package:flame/components.dart';
+import 'package:flame_forge2d/flame_forge2d.dart';
+import 'package:flutter_test/flutter_test.dart';
+import 'package:mocktail/mocktail.dart';
+import 'package:pinball/game/game.dart';
+
+class MockHasScore extends Mock with ScorePoints {}
+
+class MockBall extends Mock implements Ball {}
+
+class MockGameBloc extends Mock implements GameBloc {}
+
+class MockPinballGame extends Mock implements PinballGame {}
+
+class FakeContact extends Fake implements Contact {}
+
+void main() {
+  group('BallHasScoreCallback', () {
+    late MockPinballGame game;
+    late MockGameBloc bloc;
+    late MockBall ball;
+    late MockHasScore hasScore;
+
+    setUp(() {
+      game = MockPinballGame();
+      bloc = MockGameBloc();
+      ball = MockBall();
+      hasScore = MockHasScore();
+    });
+
+    group('begin', () {
+      test(
+        'emits Scored event with points',
+        () {
+          const points = 2;
+
+          when<PinballGame>(() => ball.gameRef).thenReturn(game);
+          when<GameBloc>(game.read).thenReturn(bloc);
+          when<int>(() => hasScore.points).thenReturn(points);
+
+          BallHasScoreCallback().begin(
+            ball,
+            hasScore,
+            FakeContact(),
+          );
+
+          verify(
+            () => bloc.add(const Scored(points: points)),
+          ).called(1);
+        },
+      );
+    });
+
+    group('end', () {
+      test('does nothing', () {
+        // TODO(alestiago): Write test.
+      });
+    });
+  });
+}