diff --git a/X10D.Tests/src/Net/EndPointTests.cs b/X10D.Tests/src/Net/EndPointTests.cs
index 8bb38e0..fd3afb0 100644
--- a/X10D.Tests/src/Net/EndPointTests.cs
+++ b/X10D.Tests/src/Net/EndPointTests.cs
@@ -13,42 +13,42 @@ public class EndPointTests
         Assert.ThrowsException<ArgumentNullException>(() => ((IPEndPoint?)null)!.GetHost());
         Assert.ThrowsException<ArgumentNullException>(() => ((DnsEndPoint?)null)!.GetHost());
     }
-    
+
     [TestMethod]
     public void GetPort_Null_ShouldThrow()
     {
         Assert.ThrowsException<ArgumentNullException>(() => ((IPEndPoint?)null)!.GetPort());
         Assert.ThrowsException<ArgumentNullException>(() => ((DnsEndPoint?)null)!.GetPort());
     }
-    
+
     [TestMethod]
     public void DnsEndPoint_GetHost_Localhost()
     {
         var endPoint = new DnsEndPoint("localhost", 1234);
         Assert.AreEqual("localhost", endPoint.GetHost());
     }
-    
+
     [TestMethod]
     public void DnsEndPoint_GetPort_1234()
     {
         var endPoint = new DnsEndPoint("localhost", 1234);
         Assert.AreEqual(1234, endPoint.GetPort());
     }
-    
+
     [TestMethod]
     public void IPEndPoint_IPv4_Loopback_GetHost_127_0_0_1()
     {
         var endPoint = new IPEndPoint(IPAddress.Loopback, 1234);
         Assert.AreEqual("127.0.0.1", endPoint.GetHost());
     }
-    
+
     [TestMethod]
     public void IPEndPoint_IPv6_Loopback_GetHost_ColonColon1()
     {
         var endPoint = new IPEndPoint(IPAddress.IPv6Loopback, 1234);
         Assert.AreEqual("::1", endPoint.GetHost());
     }
-    
+
     [TestMethod]
     public void IPEndPoint_GetPort_1234()
     {
diff --git a/X10D.Tests/src/Net/IpAddressTests.cs b/X10D.Tests/src/Net/IpAddressTests.cs
new file mode 100644
index 0000000..630216f
--- /dev/null
+++ b/X10D.Tests/src/Net/IpAddressTests.cs
@@ -0,0 +1,33 @@
+using System.Net;
+using Microsoft.VisualStudio.TestTools.UnitTesting;
+using X10D.Net;
+
+namespace X10D.Tests.Net;
+
+[TestClass]
+public class IpAddressTests
+{
+    private IPAddress _ipv4Address = null!;
+    private IPAddress _ipv6Address = null!;
+
+    [TestInitialize]
+    public void Initialize()
+    {
+        _ipv4Address = IPAddress.Parse("127.0.0.1");
+        _ipv6Address = IPAddress.Parse("::1");
+    }
+
+    [TestMethod]
+    public void IsIPv4()
+    {
+        Assert.IsTrue(_ipv4Address.IsIpV4());
+        Assert.IsFalse(_ipv6Address.IsIpV4());
+    }
+
+    [TestMethod]
+    public void IsIPv6()
+    {
+        Assert.IsTrue(_ipv6Address.IsIpV6());
+        Assert.IsFalse(_ipv4Address.IsIpV6());
+    }
+}