Add unit test for IpUtility

test/Fluxzy.Tests/UnitTests/Pcap/IpUtilityTests.cs

@@ -0,0 +1,38 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+using Fluxzy.Core.Pcap;
+using Xunit;
+
+namespace Fluxzy.Tests.UnitTests.Pcap
+{
+    public class IpUtilityTests
+    {
+        [Fact]
+        public void DefaultRoute()
+        {
+            var firstAddr = IpUtility.GetDefaultRouteV4Address();
+            var secondAddr = IpUtility.GetDefaultRouteV4Address();
+
+            Assert.True(object.ReferenceEquals(firstAddr, secondAddr));
+        }
+
+        [Fact]
+        public void GetFreeEndPoint()
+        {
+            var endPoint = IpUtility.GetFreeEndpoint();
+
+            Assert.True(endPoint.Port > 0);
+        }
+
+        [Fact]
+        public void CaptureAvailabilityChecker_Available()
+        {
+            var available = CaptureAvailabilityChecker.Instance.IsAvailable;
+
+            Assert.True(available);
+        }
+    }
+}