public void FlatGraphTest()
        {
            var flatGraph = GraphConnectedComponents.FlatGraph(graph);

            Assert.AreEqual(19, flatGraph.Nodes.Count, "Expected 19 nodes in flatGraph (14 nodes + 5 clusters)");
            Assert.AreEqual(15, flatGraph.Edges.Count, "Expected 15 edges in flatGraph (5 root edges + 10 cluster edges)");
        }