Useful for testing graph algorithms

TestGraph.cs

//Latest version here: https://gist.github.com/1c20bc400beabef79f390a876758bb4e.git
using System;
using System.Collections.Generic;
using System.Linq;

namespace TestGraphUtils
{
    /// <summary>
    /// Useful graph builder for testing algorithms
    /// </summary>
    public partial class TestGraphNode
    {
        public string Name { get; set; }
        public Dictionary<object, object> Data { get; }= new Dictionary<object, object>();

        public List<TestGraphNode> IncomingLinks { get; } = new List<TestGraphNode>();
        public List<TestGraphNode> Links { get; } = new List<TestGraphNode>();
        public TestGraphNode Link(params TestGraphNode[] nodes)
        {
            Links.AddRange(nodes);
            foreach (var n in nodes)
            {
                n.IncomingLinks.Add(this);
            }
            return this;
        }
        public TestGraphNode Link(Action<TestGraphNode> afterAdd = null, Action<TestGraphNode> beforeAdd = null)
        {
            var n = new TestGraphNode();
            beforeAdd?.Invoke(n);
            var res = Link(n);
            afterAdd?.Invoke(n);
            return res;
        }

        public TestGraphNode TopParent { get { return IncomingLinks.FirstOrDefault(); } }
        public int? IndexInParent { get { return TopParent?.Links.IndexOf(this); } }
        public IEnumerable<TestGraphNode> GetTopParents()
        {
            var current = TopParent;
            while (current != null)
            {
                yield return current;
                current = current.TopParent;
            }
        }
        public IEnumerable<TestGraphNode> GetSelfAndTopParents()
        {
            yield return this;
            foreach (var p in GetTopParents())
            {
                yield return p;
            }
        }

        public string Title { get { return Name ?? ((IndexInParent + 1)?.ToString()) ?? "(root)"; } }

        public override string ToString()
        {
            if (TopParent == null) return Title;
            return TopParent.ToString() + "\\" + Title;
        }

        public static TestGraphNode GenerateTestGraph()
        {
            var root = new TestGraphNode()
                .Link()//0.1
                .Link(n2 => {//0.2
                    n2
                            .Link()//0.2.1
                            .Link();//0.2.2
                })
                .Link(n3 => {
                })//0.3
                 ;
            return root;
        }

    }
}