public void Copy()
{
var causalities = new Stack <Causality>();
causalities.Push(new Causality(new Port("x")));
causalities.Push(new Causality(new Port("y")));
var sut = new CausalityStack(causalities);
var copyOfSut = sut.Copy();
Assert.AreNotSame(copyOfSut, sut);
Assert.AreEqual("y", copyOfSut.Peek().Port.Fullname);
copyOfSut.Pop();
Assert.AreEqual("x", copyOfSut.Peek().Port.Fullname);
copyOfSut.Pop();
Assert.IsTrue(copyOfSut.IsEmpty);
Assert.AreEqual(2, causalities.Count);
}
