public void SingleSourceTest2()
{
var graf = new Graf<char>();
var rVertex = new Vertex<char>('r');
var sVertex = new Vertex<char>('s');
var tVertex = new Vertex<char>('t');
var xVertex = new Vertex<char>('x');
var yVertex = new Vertex<char>('y');
var zVertex = new Vertex<char>('z');
rVertex.AddDirectedEdge(5, sVertex);
rVertex.AddDirectedEdge(3, tVertex);
sVertex.AddDirectedEdge(2, tVertex);
sVertex.AddDirectedEdge(6, xVertex);
tVertex.AddDirectedEdge(7, xVertex);
tVertex.AddDirectedEdge(4, yVertex);
tVertex.AddDirectedEdge(2, zVertex);
xVertex.AddDirectedEdge(-1, yVertex);
xVertex.AddDirectedEdge(-2, zVertex);
yVertex.AddDirectedEdge(-2, zVertex);
graf.AddVertex(rVertex);
graf.AddVertex(sVertex);
graf.AddVertex(tVertex);
graf.AddVertex(xVertex);
graf.AddVertex(yVertex);
graf.AddVertex(zVertex);
graf.TopologicalShortestPaths(sVertex);
var topologicalSort = graf.GetTopologicalSort().ToList();
Assert.NotNull(topologicalSort);
Assert.Equal(double.PositiveInfinity, rVertex.DiscoveryTime);
Assert.Equal(0, sVertex.DiscoveryTime);
Assert.Equal(2, tVertex.DiscoveryTime);
Assert.Equal(6, xVertex.DiscoveryTime);
Assert.Equal(5, yVertex.DiscoveryTime);
Assert.Equal(3, zVertex.DiscoveryTime);
}