public void GivenMultipleElementAreInTheModelWhenSwapElementIsCalledOrderIsChanged()
{
DsmElementModel model = new DsmElementModel();
Assert.AreEqual(1, model.GetElementCount());
IDsmElement a = model.AddElement("a", "", null);
Assert.AreEqual(1, a.Id);
IDsmElement a1 = model.AddElement("a1", "eta", a.Id);
Assert.AreEqual(2, a1.Id);
IDsmElement a2 = model.AddElement("a2", "eta", a.Id);
Assert.AreEqual(3, a2.Id);
IDsmElement a3 = model.AddElement("a3", "eta", a.Id);
Assert.AreEqual(4, a3.Id);
List <IDsmElement> rootElementsBefore = model.GetRootElement().Children.ToList();
Assert.AreEqual(1, rootElementsBefore.Count);
Assert.AreEqual(a, rootElementsBefore[0]);
Assert.AreEqual(3, rootElementsBefore[0].Children.Count);
Assert.AreEqual(a1, rootElementsBefore[0].Children[0]);
Assert.AreEqual(a2, rootElementsBefore[0].Children[1]);
Assert.AreEqual(a3, rootElementsBefore[0].Children[2]);
model.Swap(a1, a2);
List <IDsmElement> rootElementsAfter = model.GetRootElement().Children.ToList();
Assert.AreEqual(1, rootElementsAfter.Count);
Assert.AreEqual(a, rootElementsAfter[0]);
Assert.AreEqual(3, rootElementsAfter[0].Children.Count);
Assert.AreEqual(a2, rootElementsAfter[0].Children[0]);
Assert.AreEqual(a1, rootElementsAfter[0].Children[1]);
Assert.AreEqual(a3, rootElementsAfter[0].Children[2]);
}