chore: Reduce test memory footprint to reduce flakey tests

src/engine/Engine.ts

@@ -365,6 +365,7 @@ export class Engine<TKnownScenes extends string = any> implements CanInitialize,
 
     return value;
   }
+  static InstanceCount = 0;
 
   /**
    * Anything run under scope can use `useEngine()` to inject the current engine
@@ -969,6 +970,7 @@ O|===|* >________________>\n\
     this._initialize(options);
 
     (window as any).___EXCALIBUR_DEVTOOL = this;
+    Engine.InstanceCount++;
   }
 
   private _handleWebGLContextLost = (e: Event) => {
@@ -1131,6 +1133,7 @@ O|===|* >________________>\n\
       this.screen.dispose();
       this.graphicsContext.dispose();
       this.graphicsContext = null;
+      Engine.InstanceCount--;
     }
   }
 

src/engine/Util/Util.ts

@@ -7,8 +7,11 @@ import { Future } from './Future';
  */
 export function getPosition(el: HTMLElement): Vector {
   // do we need the scroll too? technically the offset method before did that
-  const rect = el.getBoundingClientRect();
-  return vec(rect.x + window.scrollX, rect.y + window.scrollY);
+  if (el) {
+    const rect = el.getBoundingClientRect();
+    return vec(rect.x + window.scrollX, rect.y + window.scrollY);
+  }
+  return Vector.Zero;
 }
 
 /**

src/spec/ActorSpec.ts

@@ -168,6 +168,7 @@ describe('A game actor', () => {
     parent.addChild(child);
 
     expect(child.scene).toBe(engine.currentScene);
+    engine.dispose();
   });
 
   it('should create actor with valid default options', () => {
@@ -632,6 +633,7 @@ describe('A game actor', () => {
 
   it('once killed is not drawn', async () => {
     engine.stop();
+    engine.dispose();
     engine = null;
     engine = TestUtils.engine({ width: 100, height: 100 });
     await TestUtils.runToReady(engine);
@@ -688,6 +690,10 @@ describe('A game actor', () => {
   });
 
   it('can be drawn with a z-index', async () => {
+    engine.stop();
+    engine.dispose();
+    engine = null;
+
     engine = TestUtils.engine({
       width: 100,
       height: 100,
@@ -726,6 +732,10 @@ describe('A game actor', () => {
   });
 
   it('can have a graphic drawn at an opacity', async () => {
+    engine.stop();
+    engine.dispose();
+    engine = null;
+
     engine = TestUtils.engine({
       width: 62,
       height: 64,

src/spec/ArcadeSolverSpec.ts

@@ -89,6 +89,8 @@ describe('An ArcadeSolver', () => {
 
     // give player right velocity
     ex.Physics.acc = ex.Vector.Zero;
+
+    game.dispose();
   });
 
   it('should cancel collision contacts where there is no more overlap', () => {
@@ -319,5 +321,7 @@ describe('An ArcadeSolver', () => {
     for (let i = 0; i < 40; i++) {
       clock.step(16);
     }
+
+    game.dispose();
   });
 });

src/spec/CameraSpec.ts

@@ -42,6 +42,8 @@ describe('A camera', () => {
   });
 
   it('should be center screen by default (when loading not complete)', () => {
+    engine.dispose();
+    engine = null;
     engine = TestUtils.engine({
       viewport: {width: 100, height: 100},
       resolution: {width: 1000, height: 1200 }
@@ -60,6 +62,8 @@ describe('A camera', () => {
   });
 
   it('should run strategies on initialize for the first frame', () => {
+    engine.dispose();
+    engine = null;
     engine = TestUtils.engine({
       viewport: {width: 100, height: 100},
       resolution: {width: 1000, height: 1200 }
@@ -74,6 +78,8 @@ describe('A camera', () => {
   });
 
   it('should update viewport on initialize for the first frame', () => {
+    engine.dispose();
+    engine = null;
     engine = TestUtils.engine({
       viewport: {width: 100, height: 100},
       resolution: {width: 1000, height: 1200 }
@@ -89,6 +95,8 @@ describe('A camera', () => {
   });
 
   it('should be center screen by default (when loading complete)', () => {
+    engine.dispose();
+    engine = null;
     engine = TestUtils.engine({
       viewport: {width: 100, height: 100},
       resolution: {width: 1000, height: 1200 }

src/spec/CanvasSpec.ts

@@ -136,6 +136,6 @@ describe('A Canvas Graphic', () => {
     expect(sut.width).toBe(50);
     expect(sut.height).toBe(50);
     await expectAsync(engine.canvas).toEqualImage('src/spec/images/GraphicsCanvasSpec/centered.png');
-
+    engine.dispose();
   });
 });

src/spec/CollisionShapeSpec.ts

@@ -33,6 +33,7 @@ describe('Collision Shape', () => {
 
     afterEach(() => {
       engine.stop();
+      engine.dispose();
       engine = null;
     });
 
@@ -442,6 +443,7 @@ describe('Collision Shape', () => {
 
     afterEach(() => {
       engine.stop();
+      engine.dispose();
       engine = null;
     });
 
@@ -830,6 +832,7 @@ describe('Collision Shape', () => {
 
     afterEach(() => {
       engine.stop();
+      engine.dispose();
       engine = null;
     });
 

src/spec/CoroutineSpec.ts

@@ -164,6 +164,7 @@ describe('A Coroutine', () => {
       await expectAsync(postdraw).toBeResolved();
       await expectAsync(postframe).toBeResolved();
     });
+    engine.dispose();
   });
 
 
@@ -184,6 +185,7 @@ describe('A Coroutine', () => {
       clock.step(100);
       await expectAsync(result).toBeResolved();
     });
+    engine.dispose();
   });
 
   it('can wait for a promise', async () => {
@@ -207,6 +209,7 @@ describe('A Coroutine', () => {
       clock.step(100);
       await expectAsync(result).toBeResolved();
     });
+    engine.dispose();
   });
 
   it('can throw error', async () => {

src/spec/DebugSystemSpec.ts

@@ -19,6 +19,7 @@ describe('DebugSystem', () => {
 
   afterEach(() => {
     engine.stop();
+    engine.dispose();
     engine = null;
   });
 

src/spec/DefaultLoaderSpec.ts

@@ -11,6 +11,12 @@ describe('A DefaultLoader', () => {
     engine = TestUtils.engine();
   });
 
+  afterEach(() => {
+    engine.stop();
+    engine.dispose();
+    engine = null;
+  });
+
   it('exists', () => {
     expect(ex.DefaultLoader).toBeDefined();
   });

src/spec/DirectorSpec.ts

@@ -25,6 +25,7 @@ describe('A Director', () => {
     expect(sut.getSceneInstance('scene2')).not.toBe(null);
     expect(sut.getSceneInstance('scene3')).not.toBe(null);
     expect(sut.getSceneInstance('scene4')).not.toBe(null);
+    engine.dispose();
   });
 
   it('can be constructed with a varied loaders', () => {
@@ -42,6 +43,7 @@ describe('A Director', () => {
     expect(sut.getSceneInstance('scene2')).not.toBe(null);
     expect(sut.getSceneInstance('scene3')).not.toBe(null);
     expect(sut.getSceneInstance('scene4')).not.toBe(null);
+    engine.dispose();
   });
 
   it('can configure start, non deferred', async () => {
@@ -92,6 +94,7 @@ describe('A Director', () => {
     expect(sut.currentTransition).toBe(fadeIn);
     expect(sut.currentSceneName).toBe('scene1');
     expect(sut.currentScene).toBe(scene1);
+    engine.dispose();
   });
 
   it('will draw a start scene transition', async () => {
@@ -131,6 +134,7 @@ describe('A Director', () => {
     expect(sut.currentScene).toBe(scene1);
 
     await expectAsync(engine.canvas).toEqualImage('/src/spec/images/DirectorSpec/fadein.png');
+    engine.dispose();
   });
 
   it('will run the loader cycle on a scene only once', async () => {
@@ -152,6 +156,7 @@ describe('A Director', () => {
     await sut.maybeLoadScene('scene1');
 
     expect(loaderSpy).toHaveBeenCalledTimes(1);
+    engine.dispose();
   });
 
   it('can remove a scene', () => {
@@ -177,6 +182,7 @@ describe('A Director', () => {
     sut.remove('scene4');
     expect(sut.getSceneDefinition('scene4')).toBe(undefined);
     expect(sut.getSceneInstance('scene4')).toBe(undefined);
+    engine.dispose();
   });
 
   it('cant remove an active scene', () => {
@@ -192,6 +198,7 @@ describe('A Director', () => {
 
     expect(() => sut.remove('root')).toThrowError('Cannot remove a currently active scene: root');
     expect(() => sut.remove(sut.rootScene)).toThrowError('Cannot remove a currently active scene: root');
+    engine.dispose();
   });
 
   it('can add a scene that was already deleted', async () => {
@@ -215,6 +222,7 @@ describe('A Director', () => {
 
     await sut.goto('scene1');
     expect(sut.currentScene).toBe(newScene);
+    engine.dispose();
   });
 
   it('can goto a scene', async () => {
@@ -243,5 +251,6 @@ describe('A Director', () => {
     await sut.goto('scene4');
     expect(sut.currentSceneName).toBe('scene4');
     expect(sut.currentScene).toBeInstanceOf(MyScene);
+    engine.dispose();
   });
 });