public void RequireSingletonWorks()
{
EmptySystem.RequireSingletonForUpdate <EcsTestData>();
EmptySystem.GetEntityQuery(typeof(EcsTestData2));
m_Manager.CreateEntity(typeof(EcsTestData2));
Assert.IsFalse(EmptySystem.ShouldRunSystem());
m_Manager.CreateEntity(typeof(EcsTestData));
Assert.IsTrue(EmptySystem.ShouldRunSystem());
}