public void FactoryShouldShouldReturnExistinInstanceHavingUsedState() { List <Flyweight> list = new List <Flyweight>() { new Flyweight("F1"), new Flyweight("F2") }; FlyweightFactory factory = new FlyweightFactory(list); Flyweight instance = factory.GetFlyweight(); instance.Should().NotBeNull(); instance.State.Should().BeEquivalentTo("used"); }