test: tested pinball_components

lib/game/components/alien_zone.dart

@@ -16,12 +16,12 @@ class AlienZone extends Blueprint {
           components: [
             AlienBumper.a(
               children: [
-                ScoringBehaviour(points: 20),
+                ScoringBehavior(points: 20),
               ],
             )..initialPosition = Vector2(-32.52, -9.1),
             AlienBumper.b(
               children: [
-                ScoringBehaviour(points: 20),
+                ScoringBehavior(points: 20),
               ],
             )..initialPosition = Vector2(-22.89, -17.35),
           ],

lib/game/components/components.dart

@@ -8,6 +8,6 @@ export 'flutter_forest.dart';
 export 'game_flow_controller.dart';
 export 'google_word/google_word.dart';
 export 'launcher.dart';
-export 'scoring_behaviour.dart';
+export 'scoring_behavior.dart';
 export 'sparky_fire_zone.dart';
 export 'wall.dart';

lib/game/components/flutter_forest.dart

@@ -20,22 +20,22 @@ class FlutterForest extends Component
           children: [
             Signpost(
               children: [
-                ScoringBehaviour(points: 20),
+                ScoringBehavior(points: 20),
               ],
             )..initialPosition = Vector2(8.35, -58.3),
             DashNestBumper.main(
               children: [
-                ScoringBehaviour(points: 20),
+                ScoringBehavior(points: 20),
               ],
             )..initialPosition = Vector2(18.55, -59.35),
             DashNestBumper.a(
               children: [
-                ScoringBehaviour(points: 20),
+                ScoringBehavior(points: 20),
               ],
             )..initialPosition = Vector2(8.95, -51.95),
             DashNestBumper.b(
               children: [
-                ScoringBehaviour(points: 20),
+                ScoringBehavior(points: 20),
               ],
             )..initialPosition = Vector2(23.3, -46.75),
             DashAnimatronic()..position = Vector2(20, -66),

lib/game/components/google_word/behaviors/google_word_bonus_behaviour.dart

@@ -1,5 +1,3 @@
-import 'dart:async';
-
 import 'package:flame/components.dart';
 import 'package:pinball/game/game.dart';
 import 'package:pinball_components/pinball_components.dart';
@@ -8,10 +6,10 @@ import 'package:pinball_flame/pinball_flame.dart';
 class GoogleWordBonusBehaviour extends Component
     with HasGameRef<PinballGame>, ParentIsA<GoogleWord> {
   @override
-  Future<void> onLoad() async {
+  void onMount() {
-    await super.onLoad();
+    super.onMount();
-    final googleLetters = parent.children.whereType<GoogleLetter>();
 
+    final googleLetters = parent.children.whereType<GoogleLetter>();
     for (final letter in googleLetters) {
       letter.bloc.stream.listen((_) {
         final achievedBonus = googleLetters

lib/game/components/google_word/google_word.dart

@@ -1,7 +1,3 @@
-// ignore_for_file: avoid_renaming_method_parameters
-
-import 'dart:async';
-
 import 'package:flame/components.dart';
 import 'package:pinball/game/components/google_word/behaviors/behaviors.dart';
 import 'package:pinball_components/pinball_components.dart';
@@ -21,12 +17,7 @@ class GoogleWord extends Component {
             GoogleLetter(3)..initialPosition = position + Vector2(2.88, -1.75),
             GoogleLetter(4)..initialPosition = position + Vector2(8.33, -0.65),
             GoogleLetter(5)..initialPosition = position + Vector2(12.92, 1.82),
+            GoogleWordBonusBehaviour(),
           ],
         );
-
-  @override
-  Future<void> onLoad() async {
-    await super.onLoad();
-    await add(GoogleWordBonusBehaviour());
-  }
 }

lib/game/components/scoring_behavior.dart

@@ -9,32 +9,14 @@ import 'package:pinball_flame/pinball_flame.dart';
 /// {@template scoring_behaviour}
 ///
 /// {@endtemplate}
-class ScoringBehaviour extends Component
+class ScoringBehavior extends ContactBehavior with HasGameRef<PinballGame> {
-    with ContactCallbacks, HasGameRef<PinballGame>, ParentIsA<BodyComponent> {
   /// {@macro scoring_behaviour}
-  ScoringBehaviour({
+  ScoringBehavior({
     required int points,
   }) : _points = points;
 
   final int _points;
 
-  @override
-  Future<void> onLoad() async {
-    await super.onLoad();
-
-    final userData = parent.body.userData;
-    if (userData is ContactCallbacksGroup) {
-      userData.addContactCallbacks(this);
-    } else if (userData is ContactCallbacks) {
-      final notifier = ContactCallbacksGroup()
-        ..addContactCallbacks(userData)
-        ..addContactCallbacks(this);
-      parent.body.userData = notifier;
-    } else {
-      parent.body.userData = this;
-    }
-  }
-
   @override
   void beginContact(Object other, Contact contact) {
     super.beginContact(other, contact);

lib/game/components/sparky_fire_zone.dart

@@ -18,17 +18,17 @@ class SparkyFireZone extends Blueprint {
           components: [
             SparkyBumper.a(
               children: [
-                ScoringBehaviour(points: 20),
+                ScoringBehavior(points: 20),
               ],
             )..initialPosition = Vector2(-22.9, -41.65),
             SparkyBumper.b(
               children: [
-                ScoringBehaviour(points: 20),
+                ScoringBehavior(points: 20),
               ],
             )..initialPosition = Vector2(-21.25, -57.9),
             SparkyBumper.c(
               children: [
-                ScoringBehaviour(points: 20),
+                ScoringBehavior(points: 20),
               ],
             )..initialPosition = Vector2(-3.3, -52.55),
             SparkyComputerSensor()..initialPosition = Vector2(-13, -49.8),

packages/pinball_components/lib/src/components/alien_bumper/alien_bumper.dart

@@ -2,6 +2,7 @@ import 'dart:async';
 
 import 'package:flame/components.dart';
 import 'package:flame_forge2d/flame_forge2d.dart';
+import 'package:flutter/material.dart';
 import 'package:pinball_components/pinball_components.dart';
 import 'package:pinball_components/src/components/alien_bumper/behaviors/behaviors.dart';
 import 'package:pinball_flame/pinball_flame.dart';
@@ -25,14 +26,14 @@ class AlienBumper extends BodyComponent with InitialPosition {
         super(
           priority: RenderPriority.alienBumper,
           children: [
-            ContactBehavior(),
+            AlienBumperBallContactBehavior(),
-            SpriteBehavior(),
+            AlienBumperBlinkingBehavior(),
             _AlienBumperSpriteGroupComponent(
               offAssetPath: offAssetPath,
               onAssetPath: onAssetPath,
               state: bloc.state,
             ),
-            if (children != null) ...children,
+            ...?children,
           ],
           renderBody: false,
         );
@@ -61,11 +62,17 @@ class AlienBumper extends BodyComponent with InitialPosition {
           children: children,
         );
 
+  /// {@macro alien_bumper}
+  @visibleForTesting
+  AlienBumper.test({
+    required this.bloc,
+  })  : _majorRadius = 3.52,
+        _minorRadius = 2.97;
+
   final double _majorRadius;
 
   final double _minorRadius;
 
-  // TODO(alestiago): Evaluate testing this.
   final AlienBumperCubit bloc;
 
   @override

packages/pinball_components/lib/src/components/alien_bumper/behaviors/alien_bumper_ball_contact_behavior.dart

@@ -1,4 +1,3 @@
-import 'package:flame/components.dart';
 import 'package:flame_forge2d/flame_forge2d.dart';
 import 'package:pinball_components/pinball_components.dart';
 import 'package:pinball_flame/pinball_flame.dart';

packages/pinball_components/lib/src/components/alien_bumper/behaviors/alien_bumper_blinking_behavior.dart

@@ -2,16 +2,14 @@ import 'package:flame/components.dart';
 import 'package:pinball_components/pinball_components.dart';
 import 'package:pinball_flame/pinball_flame.dart';
 
-/// {@template alien_bumper_sprite_behavior}
+/// {@template alien_bumper_blinking_behavior}
-///
+/// Makes a [SparkyBumper] blink back to [SparkyBumperState.active] when
+/// [SparkyBumperState.inactive].
 /// {@endtemplate}
-class SpriteBehavior extends TimerComponent with ParentIsA<AlienBumper> {
+class AlienBumperBlinkingBehavior extends TimerComponent
-  /// {@macro alien_bumper_sprite_behavior}
+    with ParentIsA<AlienBumper> {
-  SpriteBehavior()
+  /// {@macro alien_bumper_blinking_behavior}
-      : super(
+  AlienBumperBlinkingBehavior() : super(period: 0.05);
-          period: 0.05,
-          removeOnFinish: false,
-        );
 
   void _onNewState(AlienBumperState state) {
     switch (state) {
@@ -36,6 +34,6 @@ class SpriteBehavior extends TimerComponent with ParentIsA<AlienBumper> {
   @override
   void onTick() {
     super.onTick();
-    parent.bloc.onAnimated();
+    parent.bloc.onBlinked();
   }
 }

packages/pinball_components/lib/src/components/alien_bumper/behaviors/behaviors.dart

@@ -1,2 +1,2 @@
-export 'alien_bumper_ball_contact_behaviour.dart';
+export 'alien_bumper_ball_contact_behavior.dart';
-export 'sprite_behavior.dart';
+export 'alien_bumper_blinking_behavior.dart';

packages/pinball_components/lib/src/components/alien_bumper/cubit/alien_bumper_cubit.dart

@@ -9,7 +9,7 @@ class AlienBumperCubit extends Cubit<AlienBumperState> {
     emit(AlienBumperState.inactive);
   }
 
-  void onAnimated() {
+  void onBlinked() {
     emit(AlienBumperState.active);
   }
 }

packages/pinball_components/lib/src/components/dash_nest_bumper.dart

@@ -27,7 +27,7 @@ class DashNestBumper extends BodyComponent with InitialPosition {
               inactiveAssetPath: inactiveAssetPath,
               position: spritePosition,
             ),
-            if (children != null) ...children,
+            ...?children,
           ],
           renderBody: false,
         );

packages/pinball_components/lib/src/components/google_letter/google_letter.dart

@@ -13,16 +13,24 @@ export 'cubit/google_letter_cubit.dart';
 /// {@endtemplate}
 class GoogleLetter extends BodyComponent with InitialPosition {
   /// {@macro google_letter}
-  GoogleLetter(int index)
+  GoogleLetter(
-      : super(
+    int index, {
+    GoogleLetterCubit? bloc,
+  })  : bloc = bloc ?? GoogleLetterCubit(),
+        super(
           children: [
-            ContactBehavior(),
+            GoogleLetterBallContactBehavior(),
             _GoogleLetterSprite(_GoogleLetterSprite.spritePaths[index])
           ],
         );
 
-  // TODO(alestiago): Evaluate testing this.
+  final GoogleLetterCubit bloc;
-  final GoogleLetterCubit bloc = GoogleLetterCubit();
+
+  @override
+  void onRemove() {
+    bloc.close();
+    super.onRemove();
+  }
 
   @override
   Body createBody() {
@@ -57,23 +65,11 @@ class _GoogleLetterSprite extends SpriteComponent
 
   final String _path;
 
-  void _onNewState(GoogleLetterState state) {
-    switch (state) {
-      case GoogleLetterState.active:
-        add(_GoogleLetterColorEffect(color: Colors.green));
-        break;
-      case GoogleLetterState.inactive:
-        add(
-          _GoogleLetterColorEffect(color: Colors.red),
-        );
-        break;
-    }
-  }
-
   @override
   Future<void> onLoad() async {
     await super.onLoad();
-    parent.bloc.stream.listen(_onNewState);
+    // TODO(alisonryan2002): Make SpriteGroupComponent.
+    // parent.bloc.stream.listen();
 
     // TODO(alestiago): Used cached assets.
     final sprite = await gameRef.loadSprite(_path);
@@ -82,13 +78,3 @@ class _GoogleLetterSprite extends SpriteComponent
     size = sprite.originalSize / 5;
   }
 }
-
-class _GoogleLetterColorEffect extends ColorEffect {
-  _GoogleLetterColorEffect({
-    required Color color,
-  }) : super(
-          color,
-          const Offset(0, 1),
-          EffectController(duration: 0.25),
-        );
-}

packages/pinball_components/lib/src/components/signpost.dart

@@ -52,7 +52,7 @@ class Signpost extends BodyComponent with InitialPosition {
           priority: RenderPriority.signpost,
           children: [
             _SignpostSpriteComponent(),
-            if (children != null) ...children,
+            ...?children,
           ],
           renderBody: false,
         );

packages/pinball_components/lib/src/components/sparky_bumper/behaviors/behaviors.dart

@@ -1,2 +1,2 @@
-export 'sparky_bumper_ball_contact_behaviour.dart';
+export 'sparky_bumper_ball_contact_behavior.dart';
-export 'sprite_behavior.dart';
+export 'sparky_bumper_blinking_behavior.dart';

packages/pinball_components/lib/src/components/sparky_bumper/behaviors/sparky_bumper_blinking_behavior.dart

@@ -2,16 +2,14 @@ import 'package:flame/components.dart';
 import 'package:pinball_components/pinball_components.dart';
 import 'package:pinball_flame/pinball_flame.dart';
 
-/// {@template alien_bumper_sprite_behavior}
+/// {@template sparky_bumper_blinking_behavior}
-///
+/// Makes a [SparkyBumper] blink back to [SparkyBumperState.active] when
+/// [SparkyBumperState.inactive].
 /// {@endtemplate}
-class SpriteBehavior extends TimerComponent with ParentIsA<SparkyBumper> {
+class SparkyBumperBlinkingBehavior extends TimerComponent
-  /// {@macro alien_bumper_sprite_behavior}
+    with ParentIsA<SparkyBumper> {
-  SpriteBehavior()
+  /// {@macro sparky_bumper_sprite_behavior}
-      : super(
+  SparkyBumperBlinkingBehavior() : super(period: 0.05);
-          period: 0.05,
-          removeOnFinish: false,
-        );
 
   void _onNewState(SparkyBumperState state) {
     switch (state) {
@@ -36,6 +34,6 @@ class SpriteBehavior extends TimerComponent with ParentIsA<SparkyBumper> {
   @override
   void onTick() {
     super.onTick();
-    parent.bloc.onAnimated();
+    parent.bloc.onBlinked();
   }
 }

packages/pinball_components/lib/src/components/sparky_bumper/cubit/sparky_bumper_cubit.dart

@@ -7,12 +7,9 @@ class SparkyBumperCubit extends Cubit<SparkyBumperState> {
 
   void onBallContacted() {
     emit(SparkyBumperState.inactive);
-    // Future<void>.delayed(const Duration(milliseconds: 500)).whenComplete(
-    //   () => emit(AlienBumperState.active),
-    // );
   }
 
-  void onAnimated() {
+  void onBlinked() {
     emit(SparkyBumperState.active);
   }
 }

packages/pinball_components/lib/src/components/sparky_bumper/sparky_bumper.dart

@@ -2,6 +2,7 @@ import 'dart:math' as math;
 
 import 'package:flame/components.dart';
 import 'package:flame_forge2d/flame_forge2d.dart';
+import 'package:flutter/material.dart';
 import 'package:pinball_components/pinball_components.dart';
 import 'package:pinball_components/src/components/sparky_bumper/behaviors/behaviors.dart';
 import 'package:pinball_flame/pinball_flame.dart';
@@ -26,15 +27,15 @@ class SparkyBumper extends BodyComponent with InitialPosition {
         super(
           priority: RenderPriority.sparkyBumper,
           children: [
-            ContactBehavior(),
+            SparkyBumperBallContactBehavior(),
-            SpriteBehavior(),
+            SparkyBumperBlinkingBehaviour(),
             _SparkyBumperSpriteGroupComponent(
               onAssetPath: onAssetPath,
               offAssetPath: offAssetPath,
               position: spritePosition,
               state: bloc.state,
             ),
-            if (children != null) ...children,
+            ...?children,
           ],
           renderBody: false,
         );
@@ -78,12 +79,24 @@ class SparkyBumper extends BodyComponent with InitialPosition {
           children: children,
         );
 
+  /// {@macro sparky_bumper}
+  @visibleForTesting
+  SparkyBumper.test({
+    required this.bloc,
+  })  : _majorRadius = 3,
+        _minorRadius = 2.2;
+
   final double _majorRadius;
   final double _minorRadius;
 
-  // TODO(alestiago): Evaluate testing this.
   final SparkyBumperCubit bloc;
 
+  @override
+  void onRemove() {
+    bloc.close();
+    super.onRemove();
+  }
+
   @override
   Body createBody() {
     final shape = EllipseShape(

packages/pinball_components/pubspec.yaml

@@ -25,6 +25,7 @@ dependencies:
     path: ../pinball_theme
 
 dev_dependencies:
+  bloc_test: ^9.0.3
   flame_test: ^1.3.0
   flutter_test:
     sdk: flutter

packages/pinball_components/test/helpers/mocks.dart

@@ -16,3 +16,9 @@ class MockGame extends Mock implements Forge2DGame {}
 class MockContact extends Mock implements Contact {}
 
 class MockComponent extends Mock implements Component {}
+
+class MockAlienBumperCubit extends Mock implements AlienBumperCubit {}
+
+class MockGoogleLetterCubit extends Mock implements GoogleLetterCubit {}
+
+class MockSparkyBumperCubit extends Mock implements SparkyBumperCubit {}

packages/pinball_components/test/src/components/alien_bumper/alien_bumper_test.dart

@@ -1,9 +1,12 @@
 // ignore_for_file: cascade_invocations
 
+import 'package:bloc_test/bloc_test.dart';
 import 'package:flame/components.dart';
 import 'package:flame_test/flame_test.dart';
 import 'package:flutter_test/flutter_test.dart';
+import 'package:mocktail/mocktail.dart';
 import 'package:pinball_components/pinball_components.dart';
+import 'package:pinball_components/src/components/alien_bumper/behaviors/behaviors.dart';
 
 import '../../../helpers/helpers.dart';
 
@@ -19,39 +22,54 @@ void main() {
 
   group('AlienBumper', () {
     flameTester.test('"a" loads correctly', (game) async {
-      final bumper = AlienBumper.a();
+      final alienBumper = AlienBumper.a();
-      await game.ensureAdd(bumper);
+      await game.ensureAdd(alienBumper);
-
+      expect(game.contains(alienBumper), isTrue);
-      expect(game.contains(bumper), isTrue);
     });
 
     flameTester.test('"b" loads correctly', (game) async {
-      final bumper = AlienBumper.b();
+      final alienBumper = AlienBumper.b();
-      await game.ensureAdd(bumper);
+      await game.ensureAdd(alienBumper);
-      expect(game.contains(bumper), isTrue);
+      expect(game.contains(alienBumper), isTrue);
     });
 
-    flameTester.test('animate switches between on and off sprites',
+    flameTester.test('closes bloc when removed', (game) async {
-        (game) async {
+      final bloc = MockAlienBumperCubit();
-      final bumper = AlienBumper.a();
+      whenListen(
-      await game.ensureAdd(bumper);
+        bloc,
+        const Stream<AlienBumperState>.empty(),
+        initialState: AlienBumperState.active,
+      );
+      when(bloc.close).thenAnswer((_) async {});
+      final alienBumper = AlienBumper.test(bloc: bloc);
 
-      final spriteGroupComponent = bumper.firstChild<SpriteGroupComponent>()!;
+      await game.ensureAdd(alienBumper);
+      game.remove(alienBumper);
+      await game.ready();
 
-      expect(
+      verify(bloc.close).called(1);
-        spriteGroupComponent.current,
+    });
-        equals(AlienBumperState.active),
-      );
 
-      expect(
+    group('adds', () {
-        spriteGroupComponent.current,
+      flameTester.test('new children', (game) async {
-        equals(AlienBumperState.inactive),
+        final component = Component();
-      );
+        final alienBumper = AlienBumper.a(
+          children: [component],
+        );
+        await game.ensureAdd(alienBumper);
+        expect(alienBumper.children, contains(component));
+      });
 
-      expect(
+      flameTester.test('an AlienBumperBallContactBehaviour', (game) async {
-        spriteGroupComponent.current,
+        final alienBumper = AlienBumper.a();
-        equals(AlienBumperState.active),
+        await game.ensureAdd(alienBumper);
-      );
+        expect(
+          alienBumper.children
+              .whereType<AlienBumperBallContactBehavior>()
+              .single,
+          isNotNull,
+        );
+      });
     });
   });
 }

packages/pinball_components/test/src/components/alien_bumper/behaviors/alien_bumper_ball_contact_behavior_test.dart

@@ -0,0 +1,51 @@
+// ignore_for_file: cascade_invocations
+
+import 'package:bloc_test/bloc_test.dart';
+import 'package:flame_test/flame_test.dart';
+import 'package:flutter_test/flutter_test.dart';
+import 'package:mocktail/mocktail.dart';
+import 'package:pinball_components/pinball_components.dart';
+import 'package:pinball_components/src/components/alien_bumper/behaviors/alien_bumper_ball_contact_behavior.dart';
+
+import '../../../../helpers/helpers.dart';
+
+void main() {
+  TestWidgetsFlutterBinding.ensureInitialized();
+  final flameTester = FlameTester(TestGame.new);
+
+  group(
+    'AlienBumperBallContactBehavior',
+    () {
+      test('can be instantiated', () {
+        expect(
+          AlienBumperBallContactBehavior(),
+          isA<AlienBumperBallContactBehavior>(),
+        );
+      });
+
+      group(
+        'beginContact',
+        () {
+          flameTester.test('emits onBallContacted when contacts with a ball',
+              (game) async {
+            final behavior = AlienBumperBallContactBehavior();
+            final bloc = MockAlienBumperCubit();
+            whenListen(
+              bloc,
+              const Stream<AlienBumperState>.empty(),
+              initialState: AlienBumperState.active,
+            );
+
+            final alienBumper = AlienBumper.test(bloc: bloc);
+            await alienBumper.add(behavior);
+            await game.ensureAdd(alienBumper);
+
+            behavior.beginContact(MockBall(), MockContact());
+
+            verify(alienBumper.bloc.onBallContacted).called(1);
+          });
+        },
+      );
+    },
+  );
+}

packages/pinball_components/test/src/components/alien_bumper/behaviors/alien_bumper_blinking_behavior_test.dart

@@ -0,0 +1,45 @@
+import 'dart:async';
+
+import 'package:bloc_test/bloc_test.dart';
+import 'package:flame_test/flame_test.dart';
+import 'package:flutter_test/flutter_test.dart';
+import 'package:mocktail/mocktail.dart';
+import 'package:pinball_components/pinball_components.dart';
+import 'package:pinball_components/src/components/alien_bumper/behaviors/alien_bumper_blinking_behavior.dart';
+
+import '../../../../helpers/helpers.dart';
+
+void main() {
+  TestWidgetsFlutterBinding.ensureInitialized();
+  final flameTester = FlameTester(TestGame.new);
+
+  group(
+    'AlienBumperBlinkingBehaviour',
+    () {
+      flameTester.test(
+        'calls onBlinked after 0.5 seconds when inactive',
+        (game) async {
+          // TODO(alestiago): Make this pass.
+          final behavior = AlienBumperBlinkingBehavior();
+          final bloc = MockAlienBumperCubit();
+          final streamController =
+              StreamController<AlienBumperState>.broadcast();
+          whenListen(
+            bloc,
+            streamController.stream,
+            initialState: AlienBumperState.active,
+          );
+
+          final alienBumper = AlienBumper.test(bloc: bloc);
+          await alienBumper.add(behavior);
+          await game.ensureAdd(alienBumper);
+
+          streamController.sink.add(AlienBumperState.inactive);
+          game.update(0.05);
+
+          verify(bloc.onBlinked).called(1);
+        },
+      );
+    },
+  );
+}

packages/pinball_components/test/src/components/alien_bumper/cubit/alien_bumper_cubit_test.dart

@@ -0,0 +1,24 @@
+import 'package:bloc_test/bloc_test.dart';
+import 'package:flutter_test/flutter_test.dart';
+import 'package:pinball_components/pinball_components.dart';
+
+void main() {
+  group(
+    'AlienBumperCubit',
+    () {
+      blocTest<AlienBumperCubit, AlienBumperState>(
+        'onBallContacted emits inactive',
+        build: AlienBumperCubit.new,
+        act: (bloc) => bloc.onBallContacted(),
+        expect: () => [AlienBumperState.inactive],
+      );
+
+      blocTest<AlienBumperCubit, AlienBumperState>(
+        'onBlinked emits active',
+        build: AlienBumperCubit.new,
+        act: (bloc) => bloc.onBlinked(),
+        expect: () => [AlienBumperState.active],
+      );
+    },
+  );
+}

packages/pinball_components/test/src/components/dash_nest_bumper_test.dart

@@ -73,5 +73,14 @@ void main() {
         equals(DashNestBumperSpriteState.inactive),
       );
     });
+
+    flameTester.test('adds new children', (game) async {
+      final component = Component();
+      final dashNestBumper = DashNestBumper.a(
+        children: [component],
+      );
+      await game.ensureAdd(dashNestBumper);
+      expect(dashNestBumper.children, contains(component));
+    });
   });
 }

packages/pinball_components/test/src/components/google_letter/behaviors/google_letter_ball_contact_behavior_test.dart

@@ -0,0 +1,51 @@
+// ignore_for_file: cascade_invocations
+
+import 'package:bloc_test/bloc_test.dart';
+import 'package:flame_test/flame_test.dart';
+import 'package:flutter_test/flutter_test.dart';
+import 'package:mocktail/mocktail.dart';
+import 'package:pinball_components/pinball_components.dart';
+import 'package:pinball_components/src/components/google_letter/behaviors/google_letter_ball_contact_behavior.dart';
+
+import '../../../../helpers/helpers.dart';
+
+void main() {
+  TestWidgetsFlutterBinding.ensureInitialized();
+  final flameTester = FlameTester(TestGame.new);
+
+  group(
+    'GoogleLetterBallContactBehavior',
+    () {
+      test('can be instantiated', () {
+        expect(
+          GoogleLetterBallContactBehavior(),
+          isA<GoogleLetterBallContactBehavior>(),
+        );
+      });
+
+      group(
+        'beginContact',
+        () {
+          flameTester.test('emits onBallContacted when contacts with a ball',
+              (game) async {
+            final behavior = GoogleLetterBallContactBehavior();
+            final bloc = MockGoogleLetterCubit();
+            whenListen(
+              bloc,
+              const Stream<GoogleLetterState>.empty(),
+              initialState: GoogleLetterState.active,
+            );
+
+            final googleLetter = GoogleLetter(0, bloc: bloc);
+            await googleLetter.add(behavior);
+            await game.ensureAdd(googleLetter);
+
+            behavior.beginContact(MockBall(), MockContact());
+
+            verify(googleLetter.bloc.onBallContacted).called(1);
+          });
+        },
+      );
+    },
+  );
+}

packages/pinball_components/test/src/components/google_letter/cubit/google_letter_cubit_test.dart

@@ -0,0 +1,24 @@
+import 'package:bloc_test/bloc_test.dart';
+import 'package:flutter_test/flutter_test.dart';
+import 'package:pinball_components/pinball_components.dart';
+
+void main() {
+  group(
+    'GoogleLetterBumperCubit',
+    () {
+      blocTest<GoogleLetterCubit, GoogleLetterState>(
+        'onBallContacted emits active',
+        build: GoogleLetterCubit.new,
+        act: (bloc) => bloc.onBallContacted(),
+        expect: () => [GoogleLetterState.active],
+      );
+
+      blocTest<GoogleLetterCubit, GoogleLetterState>(
+        'onReset emits inactive',
+        build: GoogleLetterCubit.new,
+        act: (bloc) => bloc.onReset(),
+        expect: () => [GoogleLetterState.inactive],
+      );
+    },
+  );
+}

packages/pinball_components/test/src/components/google_letter/google_letter_test.dart

@@ -1,8 +1,11 @@
 // ignore_for_file: cascade_invocations
 
+import 'package:bloc_test/bloc_test.dart';
 import 'package:flame_test/flame_test.dart';
 import 'package:flutter_test/flutter_test.dart';
+import 'package:mocktail/mocktail.dart';
 import 'package:pinball_components/pinball_components.dart';
+import 'package:pinball_components/src/components/google_letter/behaviors/behaviors.dart';
 
 import '../../../helpers/helpers.dart';
 
@@ -81,5 +84,33 @@ void main() {
       expect(() => GoogleLetter(-1), throwsA(isA<RangeError>()));
       expect(() => GoogleLetter(6), throwsA(isA<RangeError>()));
     });
+
+    flameTester.test('closes bloc when removed', (game) async {
+      final bloc = MockGoogleLetterCubit();
+      whenListen(
+        bloc,
+        const Stream<GoogleLetterState>.empty(),
+        initialState: GoogleLetterState.active,
+      );
+      when(bloc.close).thenAnswer((_) async {});
+      final googleLetter = GoogleLetter(0, bloc: bloc);
+
+      await game.ensureAdd(googleLetter);
+      game.remove(googleLetter);
+      await game.ready();
+
+      verify(bloc.close).called(1);
+    });
+
+    flameTester.test('adds a GoogleLetterBallContactBehaviour', (game) async {
+      final googleLetter = GoogleLetter(0);
+      await game.ensureAdd(googleLetter);
+      expect(
+        googleLetter.children
+            .whereType<GoogleLetterBallContactBehavior>()
+            .single,
+        isNotNull,
+      );
+    });
   });
 }

packages/pinball_components/test/src/components/layer_sensor_test.dart

@@ -108,7 +108,7 @@ void main() {
     });
   });
 
-  group('LayerSensorBallContactCallback', () {
+  group('beginContact', () {
     late Ball ball;
     late Body body;
 
@@ -133,12 +133,14 @@ void main() {
 
       when(() => body.linearVelocity).thenReturn(Vector2(0, -1));
 
+      sensor.beginContact(ball, MockContact());
       verify(() => ball.layer = sensor.insideLayer).called(1);
       verify(() => ball.priority = sensor.insidePriority).called(1);
       verify(ball.reorderChildren).called(1);
 
       when(() => ball.layer).thenReturn(sensor.insideLayer);
 
+      sensor.beginContact(ball, MockContact());
       verify(() => ball.layer = Layer.board);
       verify(() => ball.priority = RenderPriority.ballOnBoard).called(1);
       verify(ball.reorderChildren).called(1);
@@ -156,12 +158,14 @@ void main() {
 
       when(() => body.linearVelocity).thenReturn(Vector2(0, 1));
 
+      sensor.beginContact(ball, MockContact());
       verify(() => ball.layer = sensor.insideLayer).called(1);
       verify(() => ball.priority = sensor.insidePriority).called(1);
       verify(ball.reorderChildren).called(1);
 
       when(() => ball.layer).thenReturn(sensor.insideLayer);
 
+      sensor.beginContact(ball, MockContact());
       verify(() => ball.layer = Layer.board);
       verify(() => ball.priority = RenderPriority.ballOnBoard).called(1);
       verify(ball.reorderChildren).called(1);

packages/pinball_components/test/src/components/signpost_test.dart

@@ -151,5 +151,14 @@ void main() {
         expect(spriteComponent.current, SignpostSpriteState.inactive);
       },
     );
+
+    flameTester.test('adds new children', (game) async {
+      final component = Component();
+      final signpost = Signpost(
+        children: [component],
+      );
+      await game.ensureAdd(signpost);
+      expect(signpost.children, contains(component));
+    });
   });
 }

packages/pinball_components/test/src/components/sparky_bumper/behaviors/sparky_bumper_ball_contact_behavior_test.dart

@@ -0,0 +1,51 @@
+// ignore_for_file: cascade_invocations
+
+import 'package:bloc_test/bloc_test.dart';
+import 'package:flame_test/flame_test.dart';
+import 'package:flutter_test/flutter_test.dart';
+import 'package:mocktail/mocktail.dart';
+import 'package:pinball_components/pinball_components.dart';
+import 'package:pinball_components/src/components/sparky_bumper/behaviors/sparky_bumper_ball_contact_behavior.dart';
+
+import '../../../../helpers/helpers.dart';
+
+void main() {
+  TestWidgetsFlutterBinding.ensureInitialized();
+  final flameTester = FlameTester(TestGame.new);
+
+  group(
+    'AlienBumperBallContactBehavior',
+    () {
+      test('can be instantiated', () {
+        expect(
+          SparkyBumperBallContactBehavior(),
+          isA<SparkyBumperBallContactBehavior>(),
+        );
+      });
+
+      group(
+        'beginContact',
+        () {
+          flameTester.test('emits onBallContacted when contacts with a ball',
+              (game) async {
+            final behavior = SparkyBumperBallContactBehavior();
+            final bloc = MockSparkyBumperCubit();
+            whenListen(
+              bloc,
+              const Stream<SparkyBumperState>.empty(),
+              initialState: SparkyBumperState.active,
+            );
+
+            final sparkyBumper = SparkyBumper.test(bloc: bloc);
+            await sparkyBumper.add(behavior);
+            await game.ensureAdd(sparkyBumper);
+
+            behavior.beginContact(MockBall(), MockContact());
+
+            verify(sparkyBumper.bloc.onBallContacted).called(1);
+          });
+        },
+      );
+    },
+  );
+}

packages/pinball_components/test/src/components/sparky_bumper/behaviors/sparky_bumper_blinking_behaviour_test.dart

@@ -0,0 +1,45 @@
+import 'dart:async';
+
+import 'package:bloc_test/bloc_test.dart';
+import 'package:flame_test/flame_test.dart';
+import 'package:flutter_test/flutter_test.dart';
+import 'package:mocktail/mocktail.dart';
+import 'package:pinball_components/pinball_components.dart';
+import 'package:pinball_components/src/components/sparky_bumper/behaviors/sparky_bumper_blinking_behavior.dart';
+
+import '../../../../helpers/helpers.dart';
+
+void main() {
+  TestWidgetsFlutterBinding.ensureInitialized();
+  final flameTester = FlameTester(TestGame.new);
+
+  group(
+    'SparkyBumperBlinkingBehaviour',
+    () {
+      flameTester.test(
+        'calls onBlinked after 0.5 seconds when inactive',
+        (game) async {
+          // TODO(alestiago): Make this pass.
+          final behavior = SparkyBumperBlinkingBehavior();
+          final bloc = MockSparkyBumperCubit();
+          final streamController =
+              StreamController<SparkyBumperState>.broadcast();
+          whenListen(
+            bloc,
+            streamController.stream,
+            initialState: SparkyBumperState.active,
+          );
+
+          final sparkyBumper = SparkyBumper.test(bloc: bloc);
+          await sparkyBumper.add(behavior);
+          await game.ensureAdd(sparkyBumper);
+
+          streamController.sink.add(SparkyBumperState.inactive);
+          game.update(0.05);
+
+          verify(bloc.onBlinked).called(1);
+        },
+      );
+    },
+  );
+}

packages/pinball_components/test/src/components/sparky_bumper/cubit/sparky_bumper_cubit_test.dart

@@ -0,0 +1,24 @@
+import 'package:bloc_test/bloc_test.dart';
+import 'package:flutter_test/flutter_test.dart';
+import 'package:pinball_components/pinball_components.dart';
+
+void main() {
+  group(
+    'SparkyBumperCubit',
+    () {
+      blocTest<SparkyBumperCubit, SparkyBumperState>(
+        'onBallContacted emits inactive',
+        build: SparkyBumperCubit.new,
+        act: (bloc) => bloc.onBallContacted(),
+        expect: () => [SparkyBumperState.inactive],
+      );
+
+      blocTest<SparkyBumperCubit, SparkyBumperState>(
+        'onBlinked emits active',
+        build: SparkyBumperCubit.new,
+        act: (bloc) => bloc.onBlinked(),
+        expect: () => [SparkyBumperState.active],
+      );
+    },
+  );
+}

packages/pinball_components/test/src/components/sparky_bumper/sparky_bumper_test.dart

@@ -1,8 +1,12 @@
 // ignore_for_file: cascade_invocations
 
+import 'package:bloc_test/bloc_test.dart';
+import 'package:flame/components.dart';
 import 'package:flame_test/flame_test.dart';
 import 'package:flutter_test/flutter_test.dart';
+import 'package:mocktail/mocktail.dart';
 import 'package:pinball_components/pinball_components.dart';
+import 'package:pinball_components/src/components/sparky_bumper/behaviors/behaviors.dart';
 
 import '../../../helpers/helpers.dart';
 
@@ -20,22 +24,60 @@ void main() {
 
   group('SparkyBumper', () {
     flameTester.test('"a" loads correctly', (game) async {
-      final bumper = SparkyBumper.a();
+      final sparkyBumper = SparkyBumper.a();
-      await game.ensureAdd(bumper);
+      await game.ensureAdd(sparkyBumper);
-
+      expect(game.contains(sparkyBumper), isTrue);
-      expect(game.contains(bumper), isTrue);
     });
 
     flameTester.test('"b" loads correctly', (game) async {
-      final bumper = SparkyBumper.b();
+      final sparkyBumper = SparkyBumper.b();
-      await game.ensureAdd(bumper);
+      await game.ensureAdd(sparkyBumper);
-      expect(game.contains(bumper), isTrue);
+      expect(game.contains(sparkyBumper), isTrue);
     });
 
     flameTester.test('"c" loads correctly', (game) async {
-      final bumper = SparkyBumper.c();
+      final sparkyBumper = SparkyBumper.c();
-      await game.ensureAdd(bumper);
+      await game.ensureAdd(sparkyBumper);
-      expect(game.contains(bumper), isTrue);
+      expect(game.contains(sparkyBumper), isTrue);
+    });
+
+    flameTester.test('closes bloc when removed', (game) async {
+      final bloc = MockSparkyBumperCubit();
+      whenListen(
+        bloc,
+        const Stream<SparkyBumperState>.empty(),
+        initialState: SparkyBumperState.active,
+      );
+      when(bloc.close).thenAnswer((_) async {});
+      final sparkyBumper = SparkyBumper.test(bloc: bloc);
+
+      await game.ensureAdd(sparkyBumper);
+      game.remove(sparkyBumper);
+      await game.ready();
+
+      verify(bloc.close).called(1);
+    });
+
+    group('adds', () {
+      flameTester.test('new children', (game) async {
+        final component = Component();
+        final sparkyBumper = SparkyBumper.a(
+          children: [component],
+        );
+        await game.ensureAdd(sparkyBumper);
+        expect(sparkyBumper.children, contains(component));
+      });
+
+      flameTester.test('an SparkyBumperBallContactBehaviour', (game) async {
+        final sparkyBumper = SparkyBumper.a();
+        await game.ensureAdd(sparkyBumper);
+        expect(
+          sparkyBumper.children
+              .whereType<SparkyBumperBallContactBehavior>()
+              .single,
+          isNotNull,
+        );
+      });
     });
   });
 }

packages/pinball_flame/lib/src/contact_behavior.dart

@@ -3,16 +3,16 @@ import 'package:flame_forge2d/flame_forge2d.dart';
 import 'package:flutter/material.dart';
 import 'package:pinball_flame/pinball_flame.dart';
 
-class ContactBehavior<T extends BodyComponent> extends Component
+abstract class ContactBehavior<T extends BodyComponent> extends Component
     with ContactCallbacks, ParentIsA<T> {
   @override
   @mustCallSuper
   Future<void> onLoad() async {
     final userData = parent.body.userData;
-    if (userData is ContactCallbacksGroup) {
+    if (userData is _ContactCallbacksGroup) {
       userData.addContactCallbacks(this);
     } else if (userData is ContactCallbacks) {
-      final notifier = ContactCallbacksGroup()
+      final notifier = _ContactCallbacksGroup()
         ..addContactCallbacks(userData)
         ..addContactCallbacks(this);
       parent.body.userData = notifier;
@@ -22,7 +22,7 @@ class ContactBehavior<T extends BodyComponent> extends Component
   }
 }
 
-class ContactCallbacksGroup implements ContactCallbacks {
+class _ContactCallbacksGroup implements ContactCallbacks {
   final List<ContactCallbacks> _contactCallbacks = [];
 
   @override

packages/pinball_flame/lib/src/parent_is_a.dart

@@ -9,8 +9,7 @@ mixin ParentIsA<T extends Component> on Component {
   T get parent => super.parent! as T;
 
   @override
-  Future<void>? addToParent(Component parent) {
+  Future<void>? addToParent(covariant T parent) {
-    assert(parent is T, 'Parent must be of type $T');
     return super.addToParent(parent);
   }
 }

test/game/components/scoring_behaviour_test.dart

@@ -47,7 +47,7 @@ void main() {
         'emits Scored event with points',
         setUp: (game, tester) async {
           const points = 20;
-          final scoringBehaviour = ScoringBehaviour(points: points);
+          final scoringBehaviour = ScoringBehavior(points: points);
           await game.ensureAdd(scoringBehaviour);
 
           scoringBehaviour.beginContact(ball, MockContact());
@@ -64,7 +64,7 @@ void main() {
         'plays score sound',
         setUp: (game, tester) async {
           const points = 20;
-          final scoringBehaviour = ScoringBehaviour(points: points);
+          final scoringBehaviour = ScoringBehavior(points: points);
           await game.ensureAdd(scoringBehaviour);
 
           scoringBehaviour.beginContact(ball, MockContact());
@@ -77,7 +77,7 @@ void main() {
         "adds a ScoreText component at Ball's position with points",
         setUp: (game, tester) async {
           const points = 20;
-          final scoringBehaviour = ScoringBehaviour(points: points);
+          final scoringBehaviour = ScoringBehavior(points: points);
           await game.ensureAdd(scoringBehaviour);
 
           scoringBehaviour.beginContact(ball, MockContact());