public void New_RegisteredSystem_EntityDoesNotMeetRequirements_DoesNotRegister()
{
var system = Substitute.For <ISystem>();
system.RequiredComponents.Returns(new SystemComponents {
typeof(Appearance)
});
system.ForbiddenComponents.Returns(new SystemComponents());
engine.Register(system);
var testEntity = engine.New("testEntity");
system.DidNotReceive().AddEntity(testEntity);
}