feat: addressing PR comments

lib/game/bloc/game_state.dart

@@ -26,6 +26,9 @@ class GameState extends Equatable {
   /// Determines when the game is over.
   bool get isGameOver => balls == 0;
 
+  /// Determines when player has only one chance left.
+  bool get isLastBall => balls == 1;
+
   GameState copyWith({
     int? score,
     int? balls,

lib/game/components/ball.dart

@@ -29,18 +29,15 @@ class Ball extends BodyComponent<PinballGame>
     return world.createBody(bodyDef)..createFixture(fixtureDef);
   }
 
-  @override
-  void onRemove() {
+  void ballLost() {
     final bloc = gameRef.read<GameBloc>();
 
-    final shouldBallrespwan = bloc.state.balls > 1;
+    final shouldBallRespwan = bloc.state.balls > 1;
 
     bloc.add(const BallLost());
 
-    if (shouldBallrespwan) {
-      gameRef.resetBall();
+    if (shouldBallRespwan) {
+      gameRef.spawnBall();
     }
-
-    super.onRemove();
   }
 }

lib/game/components/wall.dart

@@ -1,10 +1,50 @@
+// ignore_for_file: avoid_renaming_method_parameters
+
 import 'package:flame_forge2d/flame_forge2d.dart';
+import 'package:pinball/game/components/components.dart';
+
+class BallWallContactCallback extends ContactCallback<Ball, Wall> {
+  @override
+  void begin(Ball ball, Wall wall, Contact contact) {
+    if (wall.type == WallType.bottom) {
+      ball
+        ..ballLost()
+        ..shouldRemove = true;
+    }
+  }
+
+  @override
+  void end(_, __, ___) {}
+}
+
+enum WallType {
+  top,
+  bottom,
+  left,
+  right,
+}
 
 class Wall extends BodyComponent {
-  Wall(this.start, this.end);
+  Wall({
+    required this.type,
+    required this.start,
+    required this.end,
+  });
+
+  factory Wall.bottom(Forge2DGame game) {
+    final bottomRight = game.screenToWorld(game.camera.viewport.effectiveSize);
+    final bottomLeft = Vector2(0, bottomRight.y);
+
+    return Wall(
+      type: WallType.bottom,
+      start: bottomRight,
+      end: bottomLeft,
+    );
+  }
 
   final Vector2 start;
   final Vector2 end;
+  final WallType type;
 
   @override
   Body createBody() {

lib/game/pinball_game.dart

@@ -1,21 +1,9 @@
-// ignore_for_file: avoid_renaming_method_parameters
-
 import 'package:flame_bloc/flame_bloc.dart';
 import 'package:flame_forge2d/flame_forge2d.dart';
 import 'package:pinball/game/game.dart';
 
-class BallWallContactCallback extends ContactCallback<Ball, Wall> {
-  @override
-  void begin(Ball ball, Wall wall, Contact contact) {
-    ball.shouldRemove = true;
-  }
-
-  @override
-  void end(_, __, ___) {}
-}
-
 class PinballGame extends Forge2DGame with FlameBloc {
-  void resetBall() {
+  void spawnBall() {
     add(Ball(position: ballStartingPosition));
   }
 
@@ -25,25 +13,14 @@ class PinballGame extends Forge2DGame with FlameBloc {
           camera.viewport.effectiveSize.y - 20,
         ),
       ) -
-      Vector2(
-        0,
-        -20,
-      );
+      Vector2(0, -20);
 
   @override
   Future<void> onLoad() async {
-    await super.onLoad();
+    spawnBall();
     addContactCallback(BallScorePointsCallback());
 
-    final topLeft = Vector2.zero();
-    final bottomRight = screenToWorld(camera.viewport.effectiveSize);
-    final bottomLeft = Vector2(topLeft.x, bottomRight.y);
-
-    await add(
-      Wall(bottomRight, bottomLeft),
-    );
+    await add(Wall.bottom(this));
     addContactCallback(BallWallContactCallback());
-
-    resetBall();
   }
 }

lib/game/view/pinball_game_view.dart

@@ -14,15 +14,7 @@ class PinballGameView extends StatelessWidget {
           showDialog<void>(
             context: context,
             builder: (_) {
-              return const Dialog(
-                child: SizedBox(
-                  width: 200,
-                  height: 200,
-                  child: Center(
-                    child: Text('Game Over'),
-                  ),
-                ),
-              );
+              return const GameOverDialog();
             },
           );
         }

lib/game/view/view.dart

@@ -1,2 +1,3 @@
 export 'pinball_game_page.dart';
 export 'pinball_game_view.dart';
+export 'widgets/widgets.dart';

lib/game/view/widgets/game_over_dialog.dart

@@ -0,0 +1,18 @@
+import 'package:flutter/material.dart';
+
+class GameOverDialog extends StatelessWidget {
+  const GameOverDialog({Key? key}) : super(key: key);
+
+  @override
+  Widget build(BuildContext context) {
+    return const Dialog(
+      child: SizedBox(
+        width: 200,
+        height: 200,
+        child: Center(
+          child: Text('Game Over'),
+        ),
+      ),
+    );
+  }
+}

lib/game/view/widgets/widgets.dart

@@ -0,0 +1 @@
+export 'game_over_dialog.dart';

test/game/bloc/game_state_test.dart

@@ -62,6 +62,32 @@ void main() {
       });
     });
 
+    group('isGameOver', () {
+      test(
+        'is true '
+        'when there is only on ball left',
+        () {
+          const gameState = GameState(
+            balls: 1,
+            score: 0,
+          );
+          expect(gameState.isLastBall, isTrue);
+        },
+      );
+
+      test(
+        'is false '
+        'when there are more balls left',
+        () {
+          const gameState = GameState(
+            balls: 2,
+            score: 0,
+          );
+          expect(gameState.isLastBall, isFalse);
+        },
+      );
+    });
+
     group('copyWith', () {
       test(
         'throws AssertionError '

test/game/components/ball_test.dart

@@ -1,10 +1,14 @@
 // ignore_for_file: cascade_invocations
 
+import 'package:bloc_test/bloc_test.dart';
 import 'package:flame_forge2d/flame_forge2d.dart';
 import 'package:flame_test/flame_test.dart';
 import 'package:flutter_test/flutter_test.dart';
+import 'package:mocktail/mocktail.dart';
 import 'package:pinball/game/game.dart';
 
+import '../../helpers/helpers.dart';
+
 void main() {
   TestWidgetsFlutterBinding.ensureInitialized();
 
@@ -79,5 +83,71 @@ void main() {
         },
       );
     });
+
+    group('resetting a ball', () {
+      late GameBloc gameBloc;
+
+      setUp(() {
+        gameBloc = MockGameBloc();
+        whenListen(
+          gameBloc,
+          const Stream<GameState>.empty(),
+          initialState: const GameState.initial(),
+        );
+      });
+
+      final tester = flameBlocTester(
+        gameBlocBuilder: () {
+          return gameBloc;
+        },
+      );
+
+      tester.widgetTest(
+        'adds BallLost to GameBloc',
+        (game, tester) async {
+          await game.ready();
+
+          game.children.whereType<Ball>().first.ballLost();
+          await tester.pump();
+
+          verify(() => gameBloc.add(const BallLost())).called(1);
+        },
+      );
+
+      tester.widgetTest(
+        'resets the ball if the game is not over',
+        (game, tester) async {
+          await game.ready();
+
+          game.children.whereType<Ball>().first.removeFromParent();
+          await game.ready(); // Making sure that all additions are done
+
+          expect(
+            game.children.whereType<Ball>().length,
+            equals(1),
+          );
+        },
+      );
+
+      tester.widgetTest(
+        'no ball is added on game over',
+        (game, tester) async {
+          whenListen(
+            gameBloc,
+            const Stream<GameState>.empty(),
+            initialState: const GameState(score: 10, balls: 1),
+          );
+          await game.ready();
+
+          game.children.whereType<Ball>().first.removeFromParent();
+          await tester.pump();
+
+          expect(
+            game.children.whereType<Ball>().length,
+            equals(0),
+          );
+        },
+      );
+    });
   });
 }

test/game/components/wall_test.dart

@@ -3,18 +3,46 @@
 import 'package:flame_forge2d/flame_forge2d.dart';
 import 'package:flame_test/flame_test.dart';
 import 'package:flutter_test/flutter_test.dart';
+import 'package:mocktail/mocktail.dart';
 import 'package:pinball/game/game.dart';
 
+import '../../helpers/helpers.dart';
+
 void main() {
   TestWidgetsFlutterBinding.ensureInitialized();
 
   group('Wall', () {
+    group('BallWallContactCallback', () {
+      test(
+        'removes the ball on begin contact when the wall is a bottom one',
+        () {
+          final game = MockPinballGame();
+          final wall = MockWall();
+          final ball = MockBall();
+
+          when(() => wall.type).thenReturn(WallType.bottom);
+          when(() => ball.gameRef).thenReturn(game);
+
+          BallWallContactCallback()
+            // Remove once https://github.com/flame-engine/flame/pull/1415
+            // is merged
+            ..end(MockBall(), MockWall(), MockContact())
+            ..begin(ball, wall, MockContact());
+
+          verify(() => ball.shouldRemove = true).called(1);
+        },
+      );
+    });
     final flameTester = FlameTester(PinballGame.new);
 
     flameTester.test(
       'loads correctly',
       (game) async {
-        final wall = Wall(Vector2.zero(), Vector2(100, 0));
+        final wall = Wall(
+          type: WallType.bottom,
+          start: Vector2.zero(),
+          end: Vector2(100, 0),
+        );
         await game.ensureAdd(wall);
 
         expect(game.contains(wall), isTrue);
@@ -25,7 +53,11 @@ void main() {
       flameTester.test(
         'positions correctly',
         (game) async {
-          final wall = Wall(Vector2.zero(), Vector2(100, 0));
+          final wall = Wall(
+            type: WallType.top,
+            start: Vector2.zero(),
+            end: Vector2(100, 0),
+          );
           await game.ensureAdd(wall);
           game.contains(wall);
 
@@ -36,7 +68,11 @@ void main() {
       flameTester.test(
         'is static',
         (game) async {
-          final wall = Wall(Vector2.zero(), Vector2(100, 0));
+          final wall = Wall(
+            type: WallType.top,
+            start: Vector2.zero(),
+            end: Vector2(100, 0),
+          );
           await game.ensureAdd(wall);
 
           expect(wall.body.bodyType, equals(BodyType.static));
@@ -48,7 +84,11 @@ void main() {
       flameTester.test(
         'exists',
         (game) async {
-          final wall = Wall(Vector2.zero(), Vector2(100, 0));
+          final wall = Wall(
+            type: WallType.top,
+            start: Vector2.zero(),
+            end: Vector2(100, 0),
+          );
           await game.ensureAdd(wall);
 
           expect(wall.body.fixtures[0], isA<Fixture>());
@@ -58,7 +98,11 @@ void main() {
       flameTester.test(
         'has restitution equals 0',
         (game) async {
-          final wall = Wall(Vector2.zero(), Vector2(100, 0));
+          final wall = Wall(
+            type: WallType.top,
+            start: Vector2.zero(),
+            end: Vector2(100, 0),
+          );
           await game.ensureAdd(wall);
 
           final fixture = wall.body.fixtures[0];
@@ -69,7 +113,11 @@ void main() {
       flameTester.test(
         'has friction',
         (game) async {
-          final wall = Wall(Vector2.zero(), Vector2(100, 0));
+          final wall = Wall(
+            type: WallType.top,
+            start: Vector2.zero(),
+            end: Vector2(100, 0),
+          );
           await game.ensureAdd(wall);
 
           final fixture = wall.body.fixtures[0];

test/game/pinball_game_test.dart

@@ -1,108 +1,9 @@
-import 'package:bloc_test/bloc_test.dart';
-import 'package:flame_forge2d/flame_forge2d.dart';
-import 'package:flame_test/flame_test.dart';
-import 'package:flutter_bloc/flutter_bloc.dart';
 import 'package:flutter_test/flutter_test.dart';
-import 'package:mockingjay/mockingjay.dart';
-import 'package:pinball/game/game.dart';
-
-class MockPinballGame extends Mock implements PinballGame {}
-
-class MockWall extends Mock implements Wall {}
-
-class MockBall extends Mock implements Ball {}
-
-class MockContact extends Mock implements Contact {}
-
-class MockGameBloc extends Mock implements GameBloc {}
 
 void main() {
-  // TODO(alestiago): test if [PinballGame] registers
-  // [BallScorePointsCallback] once the following issue is resolved:
-  // https://github.com/flame-engine/flame/issues/1416
   group('PinballGame', () {
-    group('BallWallContactCallback', () {
-      test('removes the ball on begin contact', () {
-        final game = MockPinballGame();
-        final wall = MockWall();
-        final ball = MockBall();
-
-        when(() => ball.gameRef).thenReturn(game);
-
-        BallWallContactCallback()
-          // Remove once https://github.com/flame-engine/flame/pull/1415
-          // is merged
-          ..end(MockBall(), MockWall(), MockContact())
-          ..begin(ball, wall, MockContact());
-
-        verify(() => ball.shouldRemove = true).called(1);
-      });
-    });
-
-    group('resetting a ball', () {
-      late GameBloc gameBloc;
-
-      setUp(() {
-        gameBloc = MockGameBloc();
-        whenListen(
-          gameBloc,
-          const Stream<GameState>.empty(),
-          initialState: const GameState.initial(),
-        );
-      });
-
-      FlameTester(
-        PinballGame.new,
-        pumpWidget: (gameWidget, tester) async {
-          await tester.pumpWidget(
-            BlocProvider.value(
-              value: gameBloc,
-              child: gameWidget,
-            ),
-          );
-        },
-      )
-        ..widgetTest('adds BallLost to GameBloc', (game, tester) async {
-          await game.ready();
-
-          game.children.whereType<Ball>().first.removeFromParent();
-          await tester.pump();
-
-          verify(() => gameBloc.add(const BallLost())).called(1);
-        })
-        ..widgetTest(
-          'resets the ball if the game is not over',
-          (game, tester) async {
-            await game.ready();
-
-            game.children.whereType<Ball>().first.removeFromParent();
-            await game.ready(); // Making sure that all additions are done
-
-            expect(
-              game.children.whereType<Ball>().length,
-              equals(1),
-            );
-          },
-        )
-        ..widgetTest(
-          'no ball is added on game over',
-          (game, tester) async {
-            whenListen(
-              gameBloc,
-              const Stream<GameState>.empty(),
-              initialState: const GameState(score: 10, balls: 1),
-            );
-            await game.ready();
-
-            game.children.whereType<Ball>().first.removeFromParent();
-            await tester.pump();
-
-            expect(
-              game.children.whereType<Ball>().length,
-              equals(0),
-            );
-          },
-        );
-    });
+    // TODO(alestiago): test if [PinballGame] registers
+    // [BallScorePointsCallback] once the following issue is resolved:
+    // https://github.com/flame-engine/flame/issues/1416
   });
 }

test/helpers/builders.dart

@@ -0,0 +1,17 @@
+import 'package:flame_test/flame_test.dart';
+import 'package:flutter_bloc/flutter_bloc.dart';
+import 'package:pinball/game/game.dart';
+
+FlameTester flameBlocTester({required GameBloc Function() gameBlocBuilder}) {
+  return FlameTester(
+    PinballGame.new,
+    pumpWidget: (gameWidget, tester) async {
+      await tester.pumpWidget(
+        BlocProvider.value(
+          value: gameBlocBuilder(),
+          child: gameWidget,
+        ),
+      );
+    },
+  );
+}

test/helpers/helpers.dart

@@ -5,4 +5,6 @@
 // license that can be found in the LICENSE file or at
 // https://opensource.org/licenses/MIT.
 
+export 'builders.dart';
+export 'mocks.dart';
 export 'pump_app.dart';

test/helpers/mocks.dart

@@ -0,0 +1,13 @@
+import 'package:flame_forge2d/flame_forge2d.dart';
+import 'package:mocktail/mocktail.dart';
+import 'package:pinball/game/game.dart';
+
+class MockPinballGame extends Mock implements PinballGame {}
+
+class MockWall extends Mock implements Wall {}
+
+class MockBall extends Mock implements Ball {}
+
+class MockContact extends Mock implements Contact {}
+
+class MockGameBloc extends Mock implements GameBloc {}

test/helpers/pump_app.dart

@@ -13,7 +13,7 @@ import 'package:mockingjay/mockingjay.dart';
 import 'package:pinball/game/game.dart';
 import 'package:pinball/l10n/l10n.dart';
 
-class MockGameBloc extends Mock implements GameBloc {}
+import 'helpers.dart';
 
 extension PumpApp on WidgetTester {
   Future<void> pumpApp(