public void AddVertexAfterTest()
{
var poly = new Polygon2D(m_arrowVertices);
var pos = new Vector2(0, 1);
poly.AddVertexAfter(pos, m_arrowVertices[0]);
Assert.AreEqual(5, poly.VertexCount);
Assert.AreEqual(pos, poly.Vertices.ToList()[1]);
Assert.Throws <ArgumentException>(() => poly.AddVertexAfter(pos, new Vector2(-99, 99)));
}