public void AddEdge_updates_incoming_and_outgoing_neighbors()
{
var vertexOne = new Vertex {
Id = 1
};
var vertexTwo = new Vertex {
Id = 2
};
var vertexThree = new Vertex {
Id = 3
};
var edgeOne = new Edge {
Id = 1
};
var edgeTwo = new Edge {
Id = 2
};
var edgeThree = new Edge {
Id = 3
};
var graph = new Multigraph <Vertex, Edge>();
graph.AddVertices(new[] { vertexOne, vertexTwo, vertexThree });
graph.AddEdge(vertexOne, vertexTwo, edgeOne);
graph.AddEdge(vertexOne, vertexThree, edgeTwo);
graph.AddEdge(vertexTwo, vertexThree, edgeThree);
Assert.Equal(2, graph.GetOutgoingNeighbors(vertexOne).Count());
Assert.Equal(2, graph.GetOutgoingNeighbors(vertexOne).Intersect(new[] { vertexTwo, vertexThree }).Count());
Assert.Equal(2, graph.GetIncomingNeighbors(vertexThree).Count());
Assert.Equal(2, graph.GetIncomingNeighbors(vertexThree).Intersect(new[] { vertexOne, vertexTwo }).Count());
}