diff --git a/app/engine.test.js b/app/engine.test.js
index b8eb5c6..dd499d0 100644
--- a/app/engine.test.js
+++ b/app/engine.test.js
@@ -10,6 +10,9 @@ class TestServer extends Server {
     super();
     this.data = {};
   }
+  async readAsset() {
+    return new ArrayBuffer(0);
+  }
   async readData(path) {
     if (path in this.data) {
       return this.data[path];
@@ -34,16 +37,17 @@ test('visibility-based updates', async () => {
     Position: {x: (RESOLUTION.x * 1.5) + 32 - 3, y: 20},
     VisibleAabb: {},
   }));
+  const {entity: mainEntity} = engine.connectedPlayers.get(0);
   // Tick and get update. Should be a full update.
   engine.tick(1);
   expect(engine.updateFor(0))
-    .to.deep.include({2: {MainEntity: {}, ...ecs.get(2).toJSON()}, 3: ecs.get(3).toJSON()});
+    .to.deep.include({[mainEntity.id]: {MainEntity: {}, ...ecs.get(mainEntity.id).toJSON()}, [entity.id]: ecs.get(entity.id).toJSON()});
   engine.setClean();
   // Tick and get update. Should be a partial update.
   engine.tick(1);
   expect(engine.updateFor(0))
     .to.deep.include({
-      3: {
+      [entity.id]: {
         Position: {x: (RESOLUTION.x * 1.5) + 32 - 1},
         VisibleAabb: {
           x0: 1199,
@@ -55,11 +59,11 @@ test('visibility-based updates', async () => {
   // Tick and get update. Should remove the entity.
   engine.tick(1);
   expect(engine.updateFor(0))
-    .to.deep.include({3: false});
+    .to.deep.include({[entity.id]: false});
   // Aim back toward visible area and tick. Should be a full update for that entity.
   engine.setClean();
   entity.Forces.forceX = -1;
   engine.tick(1);
   expect(engine.updateFor(0))
-    .to.deep.include({3: ecs.get(3).toJSON()});
+    .to.deep.include({[entity.id]: ecs.get(entity.id).toJSON()});
 });