public void AddVertexInEdgeTest()
        {
            var dcel = new DCEL();
            var v1   = dcel.AddVertex(new DCELVertex(0, 0));
            var v2   = dcel.AddVertex(new Vector2(2, 2));
            var e    = dcel.AddEdge(v1, v2);
            var v3   = dcel.AddVertexInEdge(e, new Vector2(1.5f, 1.5f));

            Assert.AreEqual(3, dcel.VertexCount);
            Assert.AreEqual(2, dcel.EdgeCount);

            var e2 = new HalfEdge(v3, v1);

            Assert.Throws <GeomException>(() => dcel.AddVertexInEdge(e2, v3.Pos));
            Assert.Throws <GeomException>(() => dcel.AddVertexInEdge(e, new Vector2(-1, -1)));
        }