diff --git a/app/ecs/ecs.test.js b/app/ecs/ecs.test.js
index 5809a32..1ac7213 100644
--- a/app/ecs/ecs.test.js
+++ b/app/ecs/ecs.test.js
@@ -231,8 +231,8 @@ test('schedules entities to be deleted when ticking systems', () => {
     .to.be.undefined;
 });
 
-test('adds components to and remove components from entities when ticking systems', () => {
-  let addLength, removeLength;
+test('adds components to and remove components from entities when ticking systems', async () => {
+  let promise;
   const ecs = new Ecs({
     Components: {Foo: wrapProperties('Foo', {bar: {type: 'uint8'}})},
     Systems: {
@@ -243,10 +243,7 @@ test('adds components to and remove components from entities when ticking system
           };
         }
         tick() {
-          this.insertComponents(1, {Foo: {}});
-        }
-        finalize() {
-          addLength = Array.from(this.select('default')).length;
+          promise = this.insertComponents(1, {Foo: {}});
         }
       },
       RemoveComponent: class extends System {
@@ -256,10 +253,9 @@ test('adds components to and remove components from entities when ticking system
           };
         }
         tick() {
+          console.log(ecs.get(1).Foo)
           this.removeComponents(1, ['Foo']);
-        }
-        finalize() {
-          removeLength = Array.from(this.select('default')).length;
+          console.log(ecs.get(1).Foo)
         }
       },
     },
@@ -267,20 +263,21 @@ test('adds components to and remove components from entities when ticking system
   ecs.system('AddComponent').active = true;
   ecs.create();
   ecs.tick(1);
-  expect(addLength)
+  await promise;
+  expect(Array.from(ecs.system('AddComponent').select('default')).length)
     .to.equal(1);
   expect(ecs.get(1).Foo)
     .to.not.be.undefined;
   ecs.system('AddComponent').active = false;
   ecs.system('RemoveComponent').active = true;
   ecs.tick(1);
-  expect(removeLength)
+  expect(Array.from(ecs.system('RemoveComponent').select('default')).length)
     .to.equal(0);
   expect(ecs.get(1).Foo)
     .to.be.undefined;
 });
 
-test('generates coalesced diffs for entity creation', async () => {
+test('generates diffs for entity creation', async () => {
   const ecs = new Ecs();
   let entity;
   entity = await ecs.create();
@@ -288,10 +285,10 @@ test('generates coalesced diffs for entity creation', async () => {
     .to.deep.equal({[entity]: {}});
 });
 
-test('generates diffs for adding and removing components', () => {
+test('generates diffs for adding and removing components', async () => {
   const ecs = new Ecs({Components: {Position}});
   let entity;
-  entity = ecs.create();
+  entity = await ecs.create();
   ecs.setClean();
   ecs.insert(entity, {Position: {x: 64}});
   expect(ecs.diff)
@@ -409,7 +406,7 @@ test('calculates entity size', () => {
     .to.equal(30);
 });
 
-test('serializes and deserializes', () => {
+test('serializes and deserializes', async () => {
   const ecs = new Ecs({Components: {Empty, Name, Position}});
   ecs.createSpecific(1, {Empty: {}, Position: {x: 64}});
   ecs.createSpecific(16, {Name: {name: 'foobar'}, Position: {x: 128}});
@@ -422,7 +419,7 @@ test('serializes and deserializes', () => {
       systems: [],
     });
   const view = Ecs.serialize(ecs);
-  const deserialized = Ecs.deserialize(
+  const deserialized = await Ecs.deserialize(
     new Ecs({Components: {Empty, Name, Position}}),
     view,
   );
@@ -442,12 +439,12 @@ test('serializes and deserializes', () => {
     .to.equal('foobar');
 });
 
-test('deserializes from compatible ECS', () => {
+test('deserializes from compatible ECS', async () => {
   const ecs = new Ecs({Components: {Empty, Name, Position}});
   ecs.createSpecific(1, {Empty: {}, Position: {x: 64}});
   ecs.createSpecific(16, {Name: {name: 'foobar'}, Position: {x: 128}});
   const view = Ecs.serialize(ecs);
-  const deserialized = Ecs.deserialize(
+  const deserialized = await Ecs.deserialize(
     new Ecs({Components: {Empty, Name}}),
     view,
   );
diff --git a/app/ecs/system.js b/app/ecs/system.js
index b4fa59d..3f9454f 100644
--- a/app/ecs/system.js
+++ b/app/ecs/system.js
@@ -47,12 +47,12 @@ export default class System {
 
   finalize() {}
 
-  insertComponents(entityId, components) {
-    this.ecs.insert(entityId, components);
+  async insertComponents(entityId, components) {
+    return this.ecs.insert(entityId, components);
   }
 
-  insertManyComponents(components) {
-    this.ecs.insertMany(components);
+  async insertManyComponents(components) {
+    return this.ecs.insertMany(components);
   }
 
   static get priority() {