fix: [#2579] Add tests confirming parent/child scene fix

src/spec/ActorSpec.ts

@@ -153,6 +153,21 @@ describe('A game actor', () => {
     expect(actor.graphics.anchor).toEqual(ex.vec(0, 0));
   });
 
+  it('will inherit the scene from the parent entity after being added', () => {
+    const parent = new ex.Actor();
+    const child = new ex.Actor();
+
+    const engine = TestUtils.engine();
+
+    engine.add(parent);
+
+    expect(parent.scene).toBe(engine.currentScene);
+
+    parent.addChild(child);
+
+    expect(child.scene).toBe(engine.currentScene);
+  });
+
   it('should create actor with valid default options', () => {
     const actor = new ex.Actor();
     expect(actor.anchor.toString()).toEqual('(0.5, 0.5)');

src/spec/EntitySpec.ts

@@ -375,7 +375,21 @@ describe('An entity', () => {
     expect(e.scene).toBe(null);
     expect(child.scene).toBe(null);
     expect(grandchild.scene).toBe(null);
+  });
+
+  it('will inherit the scene from the parent entity after being added', () => {
+    const parent = new ex.Entity([], 'parent');
+    const child = new ex.Entity([], 'child');
+
+    const scene = new ex.Scene();
 
+    scene.add(parent);
+
+    expect(parent.scene).toBe(scene);
+
+    parent.addChild(child);
+
+    expect(child.scene).toBe(scene);
   });
 
   it('can removeAllChildren correctly', () => {