diff --git a/CHANGELOG.md b/CHANGELOG.md
index e3028c9..317472c 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -9,12 +9,14 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/).
 ### Added
 - Added DtNodeQueue UnitTest [@ikpil](https://github.com/ikpil)
 - Added RcSortedQueue UnitTest [@ikpil](https://github.com/ikpil)
+- Added IComparable interface to RcAtomicLong [@ikpil](https://github.com/ikpil)
  
 ### Fixed
 
 ### Changed
 - Update Microsoft.NET.Test.Sdk 17.8.0 to 17.9.0
-
+- Enhanced ToString method of DtNode to provide more detailed information.
+ 
 ### Removed
 
 ### Special Thanks
diff --git a/src/DotRecast.Core/Collections/RcSortedQueue.cs b/src/DotRecast.Core/Collections/RcSortedQueue.cs
index 3d35193..60cc406 100644
--- a/src/DotRecast.Core/Collections/RcSortedQueue.cs
+++ b/src/DotRecast.Core/Collections/RcSortedQueue.cs
@@ -75,12 +75,18 @@ namespace DotRecast.Core.Collections
 
         public void Enqueue(T item)
         {
+            if (null == item)
+                return;
+
             _items.Add(item);
             _dirty = true;
         }
 
         public bool Remove(T item)
         {
+            if (null == item)
+                return false;
+
             //int idx = _items.BinarySearch(item, _comparer); // don't use this! Because reference types can be reused externally.
             int idx = _items.FindLastIndex(x => item.Equals(x));
             if (0 > idx)
diff --git a/src/DotRecast.Core/RcAtomicLong.cs b/src/DotRecast.Core/RcAtomicLong.cs
index 0ea3e01..f224ffa 100644
--- a/src/DotRecast.Core/RcAtomicLong.cs
+++ b/src/DotRecast.Core/RcAtomicLong.cs
@@ -1,8 +1,9 @@
-using System.Threading;
+using System;
+using System.Threading;
 
 namespace DotRecast.Core
 {
-    public class RcAtomicLong
+    public class RcAtomicLong : IComparable<RcAtomicLong>
     {
         private long _location;
 
@@ -15,6 +16,11 @@ namespace DotRecast.Core
             _location = location;
         }
 
+        public int CompareTo(RcAtomicLong other)
+        {
+            return Read().CompareTo(other.Read());
+        }
+
         public long IncrementAndGet()
         {
             return Interlocked.Increment(ref _location);
diff --git a/src/DotRecast.Detour/DtNode.cs b/src/DotRecast.Detour/DtNode.cs
index d061fe8..c1ef5cf 100644
--- a/src/DotRecast.Detour/DtNode.cs
+++ b/src/DotRecast.Detour/DtNode.cs
@@ -40,10 +40,19 @@ namespace DotRecast.Detour
         {
             this.index = index;
         }
+        
+        public static int ComparisonNodeTotal(DtNode a, DtNode b)
+        {
+            int compare = a.total.CompareTo(b.total);
+            if (0 != compare)
+                return compare;
+
+            return a.index.CompareTo(b.index);
+        }
 
         public override string ToString()
         {
-            return "Node [id=" + id + "]";
+            return $"Node [index={index} id={id} cost={cost} total={total}]";
         }
     }
 }
\ No newline at end of file
diff --git a/src/DotRecast.Detour/DtNodeQueue.cs b/src/DotRecast.Detour/DtNodeQueue.cs
index 15f0f3f..fd44bfe 100644
--- a/src/DotRecast.Detour/DtNodeQueue.cs
+++ b/src/DotRecast.Detour/DtNodeQueue.cs
@@ -28,7 +28,7 @@ namespace DotRecast.Detour
 
         public DtNodeQueue()
         {
-            m_heap = new RcSortedQueue<DtNode>((n1, n2) => n1.total.CompareTo(n2.total));
+            m_heap = new RcSortedQueue<DtNode>(DtNode.ComparisonNodeTotal);
         }
 
         public int Count()
@@ -64,7 +64,7 @@ namespace DotRecast.Detour
 
         public bool IsEmpty()
         {
-            return 0 == m_heap.Count();
+            return m_heap.IsEmpty();
         }
     }
 }
\ No newline at end of file
diff --git a/test/DotRecast.Detour.Test/DtNodeQueueTest.cs b/test/DotRecast.Detour.Test/DtNodeQueueTest.cs
index bf542c7..5e6c7ad 100644
--- a/test/DotRecast.Detour.Test/DtNodeQueueTest.cs
+++ b/test/DotRecast.Detour.Test/DtNodeQueueTest.cs
@@ -1,5 +1,5 @@
 using System.Collections.Generic;
-using System.Linq;
+using DotRecast.Core;
 using DotRecast.Core.Collections;
 using NUnit.Framework;
 
@@ -7,15 +7,8 @@ namespace DotRecast.Detour.Test;
 
 public class DtNodeQueueTest
 {
-    [Test]
-    public void TestDtNodeQueue()
+    private static List<DtNode> ShuffledNodes(int count)
     {
-        var queue = new DtNodeQueue();
-
-        // check count
-        Assert.That(queue.Count(), Is.EqualTo(0));
-
-        const int count = 1000;
         var nodes = new List<DtNode>();
         for (int i = 0; i < count; ++i)
         {
@@ -23,13 +16,97 @@ public class DtNodeQueueTest
             node.total = i;
             nodes.Add(node);
         }
-        nodes.Shuffle();
 
-        foreach (var node in nodes)
+        nodes.Shuffle();
+        return nodes;
+    }
+
+    [Test]
+    public void TestPushAndPop()
+    {
+        var queue = new DtNodeQueue();
+
+        // check count
+        Assert.That(queue.Count(), Is.EqualTo(0));
+        
+        // null push
+        queue.Push(null);
+        Assert.That(queue.Count(), Is.EqualTo(0));
+
+        // test push
+        const int count = 1000;
+        var expectedNodes = ShuffledNodes(count);
+        foreach (var node in expectedNodes)
         {
             queue.Push(node);
         }
 
         Assert.That(queue.Count(), Is.EqualTo(count));
+
+        // test pop
+        expectedNodes.Sort(DtNode.ComparisonNodeTotal);
+        foreach (var node in expectedNodes)
+        {
+            Assert.That(queue.Peek(), Is.SameAs(node));
+            Assert.That(queue.Pop(), Is.SameAs(node));
+        }
+
+        Assert.That(queue.Count(), Is.EqualTo(0));
     }
+
+    [Test]
+    public void TestClear()
+    {
+        var queue = new DtNodeQueue();
+
+        const int count = 555;
+        var expectedNodes = ShuffledNodes(count);
+        foreach (var node in expectedNodes)
+        {
+            queue.Push(node);
+        }
+
+        Assert.That(queue.Count(), Is.EqualTo(count));
+
+        queue.Clear();
+        Assert.That(queue.Count(), Is.EqualTo(0));
+        Assert.That(queue.IsEmpty(), Is.True);
+    }
+    
+    [Test]
+    public void TestModify()
+    {
+        var queue = new DtNodeQueue();
+
+        const int count = 5000;
+        var expectedNodes = ShuffledNodes(count);
+        
+        foreach (var node in expectedNodes)
+        {
+            queue.Push(node);
+        }
+
+        // check modify
+        queue.Modify(null);
+
+        // change total
+        var r = new RcRand();
+        foreach (var node in expectedNodes)
+        {
+            node.total = r.NextInt32() % (count / 50); // duplication for test
+        }
+
+        // test modify
+        foreach (var node in expectedNodes)
+        {
+            queue.Modify(node);
+        }
+        
+        // check
+        expectedNodes.Sort(DtNode.ComparisonNodeTotal);
+        foreach (var node in expectedNodes)
+        {
+            Assert.That(queue.Pop(), Is.SameAs(node));
+        }
+    } 
 }
\ No newline at end of file