feat: include `blueprints` getter (#220)

packages/pinball_flame/lib/src/blueprint.dart

@@ -18,6 +18,7 @@ class Blueprint extends Component {
   }) {
     if (components != null) _components.addAll(components);
     if (blueprints != null) {
+      _blueprints.addAll(blueprints);
       for (final blueprint in blueprints) {
         _components.addAll(blueprint.components);
       }
@@ -26,12 +27,17 @@ class Blueprint extends Component {
 
   final List<Component> _components = [];
 
+  final List<Component> _blueprints = [];
+
   Future<void> _addToParent(Component parent) async {
     await parent.addAll(_components);
   }
 
   /// Returns a copy of the components built by this blueprint.
   List<Component> get components => List.unmodifiable(_components);
+
+  /// Returns a copy of the blueprints built by this blueprint.
+  List<Component> get blueprints => List.unmodifiable(_blueprints);
 }
 
 /// Adds helper methods regarding [Blueprint]s to [FlameGame].

packages/pinball_flame/test/src/blueprint_test.dart

@@ -27,6 +27,18 @@ void main() {
       expect(blueprint.components, contains(component2));
     });
 
+    test('correctly sets and gets blueprints', () {
+      final blueprint2 = Blueprint(
+        components: [Component()],
+      );
+      final blueprint1 = Blueprint(
+        components: [Component()],
+        blueprints: [blueprint2],
+      );
+
+      expect(blueprint1.blueprints, contains(blueprint2));
+    });
+
     flameTester.test('adds the components to parent on attach', (game) async {
       final blueprint = Blueprint(
         components: [