diff --git a/Sharp7.Tests/ConnectionTest.cs b/Sharp7.Tests/ConnectionTest.cs
new file mode 100644
index 0000000..5b40c2f
--- /dev/null
+++ b/Sharp7.Tests/ConnectionTest.cs
@@ -0,0 +1,23 @@
+using System;
+using Shouldly;
+using Xunit;
+
+namespace Sharp7.Tests
+{
+    public class ConnectionTest : ServerClientTestBase
+    {
+
+        [Fact]
+        public void ClientIsNotNull()
+        {
+            Client.ShouldNotBeNull();
+        }
+
+        [Fact]
+        public void ServerIsNotNull()
+        {
+            Server.ShouldNotBeNull();
+        }
+
+    }
+}
diff --git a/Sharp7.Tests/S7Server.cs b/Sharp7.Tests/S7Server.cs
new file mode 100644
index 0000000..8f23450
--- /dev/null
+++ b/Sharp7.Tests/S7Server.cs
@@ -0,0 +1,445 @@
+using System;
+using System.Collections.Generic;
+using System.Runtime.InteropServices;
+using System.Text;
+
+namespace Sharp7.Tests
+{
+    internal class S7Consts
+    {
+        public const string S7LibName = "snap7.dll";
+    }
+    public class S7Server
+    {
+        #region [Constants, private vars and TypeDefs]
+
+        private const int MsgTextLen = 1024;
+        private const int MkEvent = 0;
+        private const int MkLog = 1;
+
+        // Server Area ID  (use with Register/unregister - Lock/unlock Area)
+        public static readonly int SrvAreaDB = 5;
+
+        // S7 Server Event Code
+        public static readonly uint EvcPdUincoming = 0x00010000;
+        public static readonly uint EvcDataRead = 0x00020000;
+        public static readonly uint EvcDataWrite = 0x00040000;
+        public static readonly uint EvcNegotiatePdu = 0x00080000;
+        public static readonly uint EvcReadSzl = 0x00100000;
+        public static readonly uint EvcClock = 0x00200000;
+        public static readonly uint EvcUpload = 0x00400000;
+        public static readonly uint EvcDownload = 0x00800000;
+        public static readonly uint EvcDirectory = 0x01000000;
+        public static readonly uint EvcSecurity = 0x02000000;
+        public static readonly uint EvcControl = 0x04000000;
+
+        [StructLayout(LayoutKind.Sequential, Pack = 1)]
+        public struct USrvEvent
+        {
+            public IntPtr EvtTime;   // It's platform dependent (32 or 64 bit)
+            public Int32 EvtSender;
+            public UInt32 EvtCode;
+            public ushort EvtRetCode;
+            public ushort EvtParam1;
+            public ushort EvtParam2;
+            public ushort EvtParam3;
+            public ushort EvtParam4;
+        }
+
+        [StructLayout(LayoutKind.Sequential, Pack = 1)]
+        public struct S7Tag
+        {
+            public Int32 Area;
+            public Int32 DBNumber;
+            public Int32 Start;
+            public Int32 Elements;
+            public Int32 WordLen;
+        }
+
+        private Dictionary<Int32, GCHandle> hArea;
+
+        private IntPtr server;
+
+        #endregion
+
+        #region [Class Control]
+
+        [DllImport(S7Consts.S7LibName)]
+        private static extern IntPtr Srv_Create();
+        /// <summary>
+        /// Create an instace of S7Server
+        /// </summary>
+        public S7Server()
+        {
+            server = Srv_Create();
+            hArea = new Dictionary<int, GCHandle>();
+        }
+
+        [DllImport(S7Consts.S7LibName)]
+        private static extern int Srv_Destroy(ref IntPtr server);
+        /// <summary>
+        /// Destroy the S7Server and free the memory
+        /// </summary>
+        ~S7Server()
+        {
+            foreach (var item in hArea)
+            {
+                GCHandle handle = item.Value;
+                if (handle != null)
+                    handle.Free();
+            }
+            Srv_Destroy(ref server);
+        }
+
+        [DllImport(S7Consts.S7LibName)]
+        private static extern int Srv_StartTo(IntPtr server, [MarshalAs(UnmanagedType.LPStr)] string address);
+        /// <summary>
+        /// Start the server to a specific Address
+        /// </summary>
+        /// <param name="address">Address for adapter selection</param>
+        /// <returns>0: No errors. Otherwise see errorcodes</returns>
+        public int StartTo(string address)
+        {
+            return Srv_StartTo(server, address);
+        }
+
+        [DllImport(S7Consts.S7LibName)]
+        private static extern int Srv_Start(IntPtr server);
+        /// <summary>
+        /// start the server
+        /// </summary>
+        /// <returns>0: No errors. Otherwise see errorcodes</returns>
+        public int Start()
+        {
+            return Srv_Start(server);
+        }
+
+        [DllImport(S7Consts.S7LibName)]
+        private static extern int Srv_Stop(IntPtr server);
+        /// <summary>
+        /// Stop the server
+        /// </summary>
+        /// <returns>0: No errors. Otherwise see errorcodes</returns>
+        public int Stop()
+        {
+            return Srv_Stop(server);
+        }
+
+        #endregion
+
+        #region [Data Areas functions]
+
+        [DllImport(S7Consts.S7LibName)]
+        private static extern int Srv_RegisterArea(IntPtr server, Int32 areaCode, Int32 index, IntPtr pUsrData, Int32 size);
+        /// <summary>
+        /// Register a PLC Area
+        /// </summary>
+        /// <typeparam name="T"></typeparam>
+        /// <param name="areaCode">Code for area identification (e.g. S7Server.SrvAreaDB)</param>
+        /// <param name="index">Area index</param>
+        /// <param name="pUsrData">Content of the area by reference</param>
+        /// <param name="size">Allocation size</param>
+        /// <returns>0: No errors. Otherwise see errorcodes</returns>
+        public int RegisterArea<T>(Int32 areaCode, Int32 index, ref T pUsrData, Int32 size)
+        {
+            Int32 areaUid = (areaCode << 16) + index;
+            GCHandle handle = GCHandle.Alloc(pUsrData, GCHandleType.Pinned);
+            int result = Srv_RegisterArea(server, areaCode, index, handle.AddrOfPinnedObject(), size);
+            if (result == 0)
+                hArea.Add(areaUid, handle);
+            else
+                handle.Free();
+            return result;
+        }
+
+        [DllImport(S7Consts.S7LibName)]
+        private static extern int Srv_UnregisterArea(IntPtr server, Int32 areaCode, Int32 index);
+        /// <summary>
+        /// Unregister a PLC area
+        /// </summary>
+        /// <param name="areaCode">Code for area identification (e.g. S7Server.SrvAreaDB)</param>
+        /// <param name="index">Area index</param>
+        /// <returns>0: No errors. Otherwise see errorcodes</returns>
+        public int UnregisterArea(Int32 areaCode, Int32 index)
+        {
+            int result = Srv_UnregisterArea(server, areaCode, index);
+            if (result == 0)
+            {
+                Int32 areaUid = (areaCode << 16) + index;
+                if (hArea.ContainsKey(areaUid)) // should be always true
+                {
+                    GCHandle handle = hArea[areaUid];
+                    if (handle != null) // should be always true
+                        handle.Free();
+                    hArea.Remove(areaUid);
+                }
+            }
+            return result;
+        }
+
+        [DllImport(S7Consts.S7LibName)]
+        private static extern int Srv_LockArea(IntPtr server, Int32 areaCode, Int32 index);
+        /// <summary>
+        /// Lock a memory area
+        /// </summary>
+        /// <param name="areaCode">Code for area identification (e.g. S7Server.SrvAreaDB)</param>
+        /// <param name="index">Area index</param>
+        /// <returns>0: No errors. Otherwise see errorcodes</returns>
+        public int LockArea(Int32 areaCode, Int32 index)
+        {
+            return Srv_LockArea(server, areaCode, index);
+        }
+
+        [DllImport(S7Consts.S7LibName)]
+        private static extern int Srv_UnlockArea(IntPtr server, Int32 areaCode, Int32 index);
+        /// <summary>
+        /// Unlock a memory area
+        /// </summary>
+        /// <param name="areaCode">Code for area identification (e.g. S7Server.SrvAreaDB)</param>
+        /// <param name="index">Area index</param>
+        /// <returns>0: No errors. Otherwise see errorcodes</returns>
+        public int UnlockArea(Int32 areaCode, Int32 index)
+        {
+            return Srv_UnlockArea(server, areaCode, index);
+        }
+
+        #endregion
+
+        #region [Notification functions (Events)]
+
+        [StructLayout(LayoutKind.Sequential, Pack = 1)]
+        public struct RwBuffer
+        {
+            [MarshalAs(UnmanagedType.ByValArray, SizeConst = 1024)] // A telegram cannot exceed PDU size (960 bytes)
+            public byte[] Data;
+        }
+        /// <summary>
+        /// Callback delegate
+        /// </summary>
+        /// <param name="usrPtr">User pointer passed back</param>
+        /// <param name="Event">Event information structure</param>
+        /// <param name="size">Size</param>
+        public delegate void SrvCallback(IntPtr usrPtr, ref USrvEvent Event, int size);
+        /// <summary>
+        /// Callback delegate for RW operation
+        /// </summary>
+        /// <param name="usrPtr">User pointer passed back</param>
+        /// <param name="sender">Sender</param>
+        /// <param name="operation">Operation type</param>
+        /// <param name="tag">Operation Tag</param>
+        /// <param name="buffer">RW Buffer</param>
+        /// <returns>0: No errors. Otherwise see errorcodes</returns>
+        public delegate int SrvRwAreaCallback(IntPtr usrPtr, int sender, int operation, ref S7Tag tag, ref RwBuffer buffer);
+
+        [DllImport(S7Consts.S7LibName)]
+        private static extern int Srv_SetEventsCallback(IntPtr server, SrvCallback callback, IntPtr usrPtr);
+        /// <summary>
+        /// Set a function callback
+        /// </summary>
+        /// <param name="callback">Callback delegate</param>
+        /// <param name="usrPtr">User pointer passed back</param>
+        /// <returns>0: No errors. Otherwise see errorcodes</returns>
+        public int SetEventsCallBack(SrvCallback callback, IntPtr usrPtr)
+        {
+            return Srv_SetEventsCallback(server, callback, usrPtr);
+        }
+
+        [DllImport(S7Consts.S7LibName)]
+        private static extern int Srv_SetReadEventsCallback(IntPtr server, SrvCallback callback, IntPtr usrPtr);
+        /// <summary>
+        /// Set a function callback for read events
+        /// </summary>
+        /// <param name="callback">Callback delegate</param>
+        /// <param name="usrPtr">User pointer passed back</param>
+        /// <returns>0: No errors. Otherwise see errorcodes</returns>
+        public int SetReadEventsCallBack(SrvCallback callback, IntPtr usrPtr)
+        {
+            return Srv_SetReadEventsCallback(server, callback, usrPtr);
+        }
+
+        [DllImport(S7Consts.S7LibName)]
+        private static extern int Srv_SetRWAreaCallback(IntPtr server, SrvRwAreaCallback callback, IntPtr usrPtr);
+        /// <summary>
+        /// Set a function callback for read-write events
+        /// </summary>
+        /// <param name="callback">Callback delegate</param>
+        /// <param name="usrPtr">User pointer passed back</param>
+        /// <returns>0: No errors. Otherwise see errorcodes</returns>
+        public int SetRwAreaCallBack(SrvRwAreaCallback callback, IntPtr usrPtr)
+        {
+            return Srv_SetRWAreaCallback(server, callback, usrPtr);
+        }
+
+        [DllImport(S7Consts.S7LibName)]
+        private static extern int Srv_PickEvent(IntPtr server, ref USrvEvent Event, ref Int32 evtReady);
+        /// <summary>
+        /// Extracts an event (if available) from the Events queue.
+        /// </summary>
+        /// <param name="Event">Reference of User event</param>
+        /// <returns>0: No errors. Otherwise see errorcodes</returns>
+        public bool PickEvent(ref USrvEvent Event)
+        {
+            Int32 evtReady = new Int32();
+            if (Srv_PickEvent(server, ref Event, ref evtReady) == 0)
+                return evtReady != 0;
+            else
+                return false;
+        }
+
+        [DllImport(S7Consts.S7LibName)]
+        private static extern int Srv_ClearEvents(IntPtr server);
+        /// <summary>
+        /// clear the event queue
+        /// </summary>
+        /// <returns>0: No errors. Otherwise see errorcodes</returns>
+        public int ClearEvents()
+        {
+            return Srv_ClearEvents(server);
+        }
+
+        [DllImport(S7Consts.S7LibName, CharSet = CharSet.Ansi)]
+        private static extern int Srv_EventText(ref USrvEvent Event, StringBuilder evtMsg, int textSize);
+        /// <summary>
+        /// retrieve a message from an event
+        /// </summary>
+        /// <param name="Event">Reference to Event</param>
+        /// <returns>The message for an event</returns>
+        public string EventText(ref USrvEvent Event)
+        {
+            StringBuilder message = new StringBuilder(MsgTextLen);
+            Srv_EventText(ref Event, message, MsgTextLen);
+            return message.ToString();
+        }
+        /// <summary>
+        /// Convet an the event time to datetime object
+        /// </summary>
+        /// <param name="timeStamp">Event Time pointer</param>
+        /// <returns>the datetime for the timestamp</returns>
+        public DateTime EvtTimeToDateTime(IntPtr timeStamp)
+        {
+            DateTime unixStartEpoch = new DateTime(1970, 1, 1, 0, 0, 0, 0);
+            return unixStartEpoch.AddSeconds(Convert.ToDouble(timeStamp));
+        }
+
+        [DllImport(S7Consts.S7LibName)]
+        private static extern int Srv_GetMask(IntPtr server, Int32 maskKind, ref UInt32 mask);
+        [DllImport(S7Consts.S7LibName)]
+        private static extern int Srv_SetMask(IntPtr server, Int32 maskKind, UInt32 mask);
+
+        // Property LogMask R/W
+        /// <summary>
+        /// Activate o deactivate the LogMask
+        /// </summary>
+        public UInt32 LogMask
+        {
+            get
+            {
+                UInt32 mask = new UInt32();
+                if (Srv_GetMask(server, S7Server.MkLog, ref mask) == 0)
+                    return mask;
+                else
+                    return 0;
+            }
+            set
+            {
+                Srv_SetMask(server, S7Server.MkLog, value);
+            }
+        }
+
+        // Property EventMask R/W
+        /// <summary>
+        /// Activate o deactivate the EventMask
+        /// </summary>
+        public UInt32 EventMask
+        {
+            get
+            {
+                UInt32 mask = new UInt32();
+                if (Srv_GetMask(server, S7Server.MkEvent, ref mask) == 0)
+                    return mask;
+                else
+                    return 0;
+            }
+            set
+            {
+                Srv_SetMask(server, S7Server.MkEvent, value);
+            }
+        }
+
+
+        #endregion
+
+        #region [Info functions]
+
+        [DllImport(S7Consts.S7LibName)]
+        private static extern int Srv_GetStatus(IntPtr server, ref Int32 serverStatus, ref Int32 cpuStatus, ref Int32 clientsCount);
+        [DllImport(S7Consts.S7LibName)]
+        private static extern int Srv_SetCpuStatus(IntPtr server, Int32 cpuStatus);
+
+        // Property Virtual CPU status R/W
+        public int CpuStatus
+        {
+            get
+            {
+                Int32 cStatus = new Int32();
+                Int32 sStatus = new Int32();
+                Int32 cCount = new Int32();
+
+                if (Srv_GetStatus(server, ref sStatus, ref cStatus, ref cCount) == 0)
+                    return cStatus;
+                else
+                    return -1;
+            }
+            set
+            {
+                Srv_SetCpuStatus(server, value);
+            }
+        }
+
+        // Property Server Status Read Only
+        public int ServerStatus
+        {
+            get
+            {
+                Int32 cStatus = new Int32();
+                Int32 sStatus = new Int32();
+                Int32 cCount = new Int32();
+                if (Srv_GetStatus(server, ref sStatus, ref cStatus, ref cCount) == 0)
+                    return sStatus;
+                else
+                    return -1;
+            }
+        }
+
+        // Property Clients Count Read Only
+        public int ClientsCount
+        {
+            get
+            {
+                Int32 cStatus = new Int32();
+                Int32 sStatus = new Int32();
+                Int32 cCount = new Int32();
+                if (Srv_GetStatus(server, ref cStatus, ref sStatus, ref cCount) == 0)
+                    return cCount;
+                else
+                    return -1;
+            }
+        }
+
+        [DllImport(S7Consts.S7LibName, CharSet = CharSet.Ansi)]
+        private static extern int Srv_ErrorText(int error, StringBuilder errMsg, int textSize);
+        /// <summary>
+        /// Retrieve the error message for an error code
+        /// </summary>
+        /// <param name="error">Error code</param>
+        /// <returns>Message for the error code</returns>
+        public string ErrorText(int error)
+        {
+            StringBuilder message = new StringBuilder(MsgTextLen);
+            Srv_ErrorText(error, message, MsgTextLen);
+            return message.ToString();
+        }
+
+        #endregion
+    }
+}
\ No newline at end of file
diff --git a/Sharp7.Tests/ServerClientTestBase.cs b/Sharp7.Tests/ServerClientTestBase.cs
new file mode 100644
index 0000000..8ff85ec
--- /dev/null
+++ b/Sharp7.Tests/ServerClientTestBase.cs
@@ -0,0 +1,26 @@
+using System;
+using System.Linq;
+using Shouldly;
+
+namespace Sharp7.Tests
+{
+    public class ServerClientTestBase : ServerTestBase, IDisposable
+    {
+        private S7Client client;
+        public S7Client Client => client;
+
+        public ServerClientTestBase() : base()
+        {
+            client = new S7Client();
+            var rc = client.ConnectTo(Localhost, 0, 2);
+            rc.ShouldBe(0);
+        }
+
+
+        public new void Dispose()
+        {
+            client.Disconnect();
+            base.Dispose();
+        }
+    }
+}
\ No newline at end of file
diff --git a/Sharp7.Tests/ServerTestBase.cs b/Sharp7.Tests/ServerTestBase.cs
new file mode 100644
index 0000000..5bd6b40
--- /dev/null
+++ b/Sharp7.Tests/ServerTestBase.cs
@@ -0,0 +1,25 @@
+using System;
+using System.Linq;
+using Shouldly;
+
+namespace Sharp7.Tests
+{
+    public class ServerTestBase : IDisposable
+    {
+        private readonly S7Server server;
+        protected readonly string Localhost = "127.0.0.1";
+        public ServerTestBase()
+        {
+            server = new S7Server();
+            var rc = server.StartTo(Localhost);
+            rc.ShouldBe(0);
+        }
+
+        public S7Server Server => server;
+
+        public void Dispose()
+        {
+            server.Stop();
+        }
+    }
+}
\ No newline at end of file
diff --git a/Sharp7.Tests/Sharp7.Tests.csproj b/Sharp7.Tests/Sharp7.Tests.csproj
new file mode 100644
index 0000000..21e3898
--- /dev/null
+++ b/Sharp7.Tests/Sharp7.Tests.csproj
@@ -0,0 +1,33 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <TargetFramework>net45</TargetFramework>
+    <Platforms>AnyCPU;x86</Platforms>
+  </PropertyGroup>
+
+  <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Debug|AnyCPU'">
+    <PlatformTarget>x86</PlatformTarget>
+  </PropertyGroup>
+
+  <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Debug|x86'">
+    <PlatformTarget>x86</PlatformTarget>
+  </PropertyGroup>
+
+  <ItemGroup>
+    <PackageReference Include="Microsoft.NET.Test.Sdk" Version="15.9.0" />
+    <PackageReference Include="Shouldly" Version="3.0.2" />
+    <PackageReference Include="xunit" Version="2.4.0" />
+    <PackageReference Include="xunit.runner.visualstudio" Version="2.4.0" />
+  </ItemGroup>
+
+  <ItemGroup>
+    <ProjectReference Include="..\Sharp7\Sharp7.csproj" />
+  </ItemGroup>
+
+  <ItemGroup>
+    <None Update="snap7.dll">
+      <CopyToOutputDirectory>PreserveNewest</CopyToOutputDirectory>
+    </None>
+  </ItemGroup>
+
+</Project>
diff --git a/Sharp7.Tests/snap7.dll b/Sharp7.Tests/snap7.dll
new file mode 100644
index 0000000..091ed77
Binary files /dev/null and b/Sharp7.Tests/snap7.dll differ
diff --git a/Sharp7.sln b/Sharp7.sln
index d04a0f4..3d14355 100644
--- a/Sharp7.sln
+++ b/Sharp7.sln
@@ -1,9 +1,11 @@
 
 Microsoft Visual Studio Solution File, Format Version 12.00
-# Visual Studio 15
-VisualStudioVersion = 15.0.27004.2009
+# Visual Studio Version 16
+VisualStudioVersion = 16.0.29306.81
 MinimumVisualStudioVersion = 10.0.40219.1
-Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "Sharp7", "Sharp7\Sharp7.csproj", "{4FE194AF-7FFE-48BA-9DFC-425E9D5B9F46}"
+Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "Sharp7", "Sharp7\Sharp7.csproj", "{4FE194AF-7FFE-48BA-9DFC-425E9D5B9F46}"
+EndProject
+Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "Sharp7.Tests", "Sharp7.Tests\Sharp7.Tests.csproj", "{A770A4B3-8BD7-49A8-BF7B-8CE1FA2E577A}"
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 	GlobalSection(SolutionConfigurationPlatforms) = preSolution
@@ -27,6 +29,18 @@ Global
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 		{4FE194AF-7FFE-48BA-9DFC-425E9D5B9F46}.Release|x86.Build.0 = Release|Any CPU
+		{A770A4B3-8BD7-49A8-BF7B-8CE1FA2E577A}.Debug|Any CPU.ActiveCfg = Debug|x86
+		{A770A4B3-8BD7-49A8-BF7B-8CE1FA2E577A}.Debug|Any CPU.Build.0 = Debug|x86
+		{A770A4B3-8BD7-49A8-BF7B-8CE1FA2E577A}.Debug|x64.ActiveCfg = Debug|Any CPU
+		{A770A4B3-8BD7-49A8-BF7B-8CE1FA2E577A}.Debug|x64.Build.0 = Debug|Any CPU
+		{A770A4B3-8BD7-49A8-BF7B-8CE1FA2E577A}.Debug|x86.ActiveCfg = Debug|Any CPU
+		{A770A4B3-8BD7-49A8-BF7B-8CE1FA2E577A}.Debug|x86.Build.0 = Debug|Any CPU
+		{A770A4B3-8BD7-49A8-BF7B-8CE1FA2E577A}.Release|Any CPU.ActiveCfg = Release|x86
+		{A770A4B3-8BD7-49A8-BF7B-8CE1FA2E577A}.Release|Any CPU.Build.0 = Release|x86
+		{A770A4B3-8BD7-49A8-BF7B-8CE1FA2E577A}.Release|x64.ActiveCfg = Release|Any CPU
+		{A770A4B3-8BD7-49A8-BF7B-8CE1FA2E577A}.Release|x64.Build.0 = Release|Any CPU
+		{A770A4B3-8BD7-49A8-BF7B-8CE1FA2E577A}.Release|x86.ActiveCfg = Release|Any CPU
+		{A770A4B3-8BD7-49A8-BF7B-8CE1FA2E577A}.Release|x86.Build.0 = Release|Any CPU
 	EndGlobalSection
 	GlobalSection(SolutionProperties) = preSolution
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