EntitySystemBuilder builder = new EntitySystemBuilder();
entityManager = builder.build(moduleManager.getEnvironment(), mock(NetworkSystem.class), new ReflectionReflectFactory());
entityManager.getComponentLibrary().register(new SimpleUri("test", "gettersetter"), GetterSetterComponent.class);
entityManager.getComponentLibrary().register(new SimpleUri("test", "string"), StringComponent.class);
entityManager.getComponentLibrary().register(new SimpleUri("test", "integer"), IntegerComponent.class);
entitySerializer = new EntitySerializer(entityManager);
componentLibrary = entityManager.getComponentLibrary();
PrefabData prefabData = new PrefabData();
prefabData.addComponent(new StringComponent("Value"));
prefab = Assets.generateAsset(new AssetUri(AssetType.PREFAB, "test:Test"), prefabData, Prefab.class);