diff --git a/.github/dependabot.yml b/.github/dependabot.yml
new file mode 100644
index 0000000..03eba18
--- /dev/null
+++ b/.github/dependabot.yml
@@ -0,0 +1,7 @@
+version: 2
+updates:
+  - package-ecosystem: "nuget"
+    directory: "/"
+    schedule:
+      interval: "weekly"
+    open-pull-requests-limit: 10
diff --git a/.github/workflows/sonarcloud.yml b/.github/workflows/sonarcloud.yml
index e784069..419e1a6 100644
--- a/.github/workflows/sonarcloud.yml
+++ b/.github/workflows/sonarcloud.yml
@@ -1,31 +1,3 @@
-# This workflow uses actions that are not certified by GitHub.
-# They are provided by a third-party and are governed by
-# separate terms of service, privacy policy, and support
-# documentation.
-
-# This workflow helps you trigger a SonarCloud analysis of your code and populates
-# GitHub Code Scanning alerts with the vulnerabilities found.
-# Free for open source project.
-
-# 1. Login to SonarCloud.io using your GitHub account
-
-# 2. Import your project on SonarCloud
-#     * Add your GitHub organization first, then add your repository as a new project.
-#     * Please note that many languages are eligible for automatic analysis,
-#       which means that the analysis will start automatically without the need to set up GitHub Actions.
-#     * This behavior can be changed in Administration > Analysis Method.
-#
-# 3. Follow the SonarCloud in-product tutorial
-#     * a. Copy/paste the Project Key and the Organization Key into the args parameter below
-#          (You'll find this information in SonarCloud. Click on "Information" at the bottom left)
-#
-#     * b. Generate a new token and add it to your Github repository's secrets using the name SONAR_TOKEN
-#          (On SonarCloud, click on your avatar on top-right > My account > Security
-#           or go directly to https://sonarcloud.io/account/security/)
-
-# Feel free to take a look at our documentation (https://docs.sonarcloud.io/getting-started/github/)
-# or reach out to our community forum if you need some help (https://community.sonarsource.com/c/help/sc/9)
-
 name: SonarCloud analysis
 
 on:
@@ -36,14 +8,16 @@ on:
   workflow_dispatch:
 
 permissions:
-  pull-requests: read # allows SonarCloud to decorate PRs with analysis results
+  pull-requests: read
 
 jobs:
   sonar-check:
     name: Sonar Check
-    runs-on: windows-latest   # безпечно для будь-яких .NET проектів
+    runs-on: windows-latest
     steps:
       - uses: actions/checkout@v4
+        env:
+          FORCE_JAVASCRIPT_ACTIONS_TO_NODE24: true
         with: { fetch-depth: 0 }
 
       - uses: actions/setup-dotnet@v4
@@ -56,8 +30,8 @@ jobs:
           dotnet tool install --global dotnet-sonarscanner
           echo "$env:USERPROFILE\.dotnet\tools" >> $env:GITHUB_PATH
           dotnet sonarscanner begin `
-          /k:"ppanchen_NetSdrClient" `
-          /o:"ppanchen" `
+          /k:"MinTins_ReengineeringCourse" `
+          /o:"roman-flakei" `
           /d:sonar.token="${{ secrets.SONAR_TOKEN }}" `
           /d:sonar.cs.opencover.reportsPaths="**/coverage.xml" `
           /d:sonar.cpd.cs.minimumTokens=40 `
@@ -65,18 +39,35 @@ jobs:
           /d:sonar.exclusions=**/bin/**,**/obj/**,**/sonarcloud.yml `
           /d:sonar.qualitygate.wait=true
         shell: pwsh
+
       # 2) BUILD & TEST
       - name: Restore
         run: dotnet restore NetSdrClient.sln
+
       - name: Build
         run: dotnet build NetSdrClient.sln -c Release --no-restore
-      #- name: Tests with coverage (OpenCover)
-      #  run: |
-      #    dotnet test NetSdrClientAppTests/NetSdrClientAppTests.csproj -c Release --no-build `
-      #      /p:CollectCoverage=true `
-      #      /p:CoverletOutput=TestResults/coverage.xml `
-      #      /p:CoverletOutputFormat=opencover
-      #  shell: pwsh
+
+      - name: Tests NetSdrClientAppTests with coverage
+        run: |
+          dotnet test NetSdrClientAppTests/NetSdrClientAppTests.csproj -c Release --no-build `
+            /p:CollectCoverage=true `
+            /p:CoverletOutput=TestResults/coverage.xml `
+            /p:CoverletOutputFormat=opencover
+        shell: pwsh
+
+      - name: Tests EchoServerTests with coverage
+        run: |
+          dotnet test EchoServerTests/EchoServerTests.csproj -c Release --no-build `
+            /p:CollectCoverage=true `
+            /p:CoverletOutput=TestResults/coverage.xml `
+            /p:CoverletOutputFormat=opencover
+        shell: pwsh
+
+      - name: Tests NetSdrArchTests
+        run: |
+          dotnet test NetSdrArchTests/NetSdrArchTests.csproj -c Release --no-build
+        shell: pwsh
+
       # 3) END: SonarScanner
       - name: SonarScanner End
         run: dotnet sonarscanner end /d:sonar.token="${{ secrets.SONAR_TOKEN }}"
diff --git a/EchoServerTests/EchoServerTests.cs b/EchoServerTests/EchoServerTests.cs
new file mode 100644
index 0000000..defcd1c
--- /dev/null
+++ b/EchoServerTests/EchoServerTests.cs
@@ -0,0 +1,266 @@
+using System.Net.Sockets;
+using System.Threading;
+using System.Threading.Tasks;
+using EchoTcpServer;
+using Moq;
+using NUnit.Framework;
+
+namespace EchoServerTests
+{
+    public class EchoServerTests
+    {
+        private Mock<ITcpListener> _listenerMock = null!;
+        private EchoServer _server = null!;
+
+        [SetUp]
+        public void Setup()
+        {
+            _listenerMock = new Mock<ITcpListener>();
+            _server = new EchoServer(_listenerMock.Object);
+        }
+
+        // ---------------------------------------------------------------
+        // StartAsync — запускає listener і зупиняється при скасуванні
+        // ---------------------------------------------------------------
+
+        [Test]
+        public async Task StartAsync_CallsListenerStart()
+        {
+            // Arrange: AcceptTcpClientAsync кидає ObjectDisposedException одразу
+            // щоб вийти з циклу без реального сокета
+            _listenerMock
+                .Setup(l => l.AcceptTcpClientAsync())
+                .ThrowsAsync(new ObjectDisposedException("listener"));
+
+            // Act
+            await _server.StartAsync();
+
+            // Assert
+            _listenerMock.Verify(l => l.Start(), Times.Once);
+        }
+
+        [Test]
+        public async Task StartAsync_ExitsLoop_OnObjectDisposedException()
+        {
+            // Arrange
+            _listenerMock
+                .Setup(l => l.AcceptTcpClientAsync())
+                .ThrowsAsync(new ObjectDisposedException("listener"));
+
+            // Act — не має зависнути
+            var task = _server.StartAsync();
+            await Task.WhenAny(task, Task.Delay(2000));
+
+            // Assert — метод завершився без timeout
+            Assert.That(task.IsCompleted, Is.True);
+        }
+
+        // ---------------------------------------------------------------
+        // Stop — скасовує токен і зупиняє listener
+        // ---------------------------------------------------------------
+
+        [Test]
+        public void Stop_CallsListenerStop()
+        {
+            // Act
+            _server.Stop();
+
+            // Assert
+            _listenerMock.Verify(l => l.Stop(), Times.Once);
+        }
+
+        [Test]
+        public void Stop_CanBeCalledWithoutStart()
+        {
+            // Act & Assert — не кидає виняток
+            Assert.DoesNotThrow(() => _server.Stop());
+        }
+
+        // ---------------------------------------------------------------
+        // HandleClientAsync — основна логіка echo
+        // ---------------------------------------------------------------
+
+        [Test]
+        public async Task HandleClientAsync_EchoesDataBack()
+        {
+            // Arrange: два TcpClient спілкуються через loopback
+            using var serverSocket = new TcpListener(System.Net.IPAddress.Loopback, 0);
+            serverSocket.Start();
+            int port = ((System.Net.IPEndPoint)serverSocket.LocalEndpoint).Port;
+
+            using var clientTcp = new TcpClient();
+            await clientTcp.ConnectAsync(System.Net.IPAddress.Loopback, port);
+            using var serverClient = await serverSocket.AcceptTcpClientAsync();
+            serverSocket.Stop();
+
+            var cts = new CancellationTokenSource();
+            var handleTask = EchoServer.HandleClientAsync(serverClient, cts.Token);
+
+            // Act: надіслати дані і прочитати echo
+            byte[] sent = new byte[] { 0x01, 0x02, 0x03, 0x04 };
+            var clientStream = clientTcp.GetStream();
+            await clientStream.WriteAsync(sent.AsMemory(0, sent.Length));
+
+            byte[] received = new byte[sent.Length];
+            int bytesRead = await clientStream.ReadAsync(received.AsMemory(0, received.Length));
+
+            // Assert
+            Assert.Multiple(() =>
+            {
+                Assert.That(bytesRead, Is.EqualTo(sent.Length));
+                Assert.That(received, Is.EqualTo(sent));
+            });
+
+            // Cleanup
+            cts.Cancel();
+            clientTcp.Close();
+            await Task.WhenAny(handleTask, Task.Delay(1000));
+        }
+
+        [Test]
+        public async Task HandleClientAsync_StopsOnCancellation()
+        {
+            // Arrange
+            using var serverSocket = new TcpListener(System.Net.IPAddress.Loopback, 0);
+            serverSocket.Start();
+            int port = ((System.Net.IPEndPoint)serverSocket.LocalEndpoint).Port;
+
+            using var clientTcp = new TcpClient();
+            await clientTcp.ConnectAsync(System.Net.IPAddress.Loopback, port);
+            using var serverClient = await serverSocket.AcceptTcpClientAsync();
+            serverSocket.Stop();
+
+            var cts = new CancellationTokenSource();
+
+            // Act: скасувати токен одразу
+            cts.Cancel();
+            var handleTask = EchoServer.HandleClientAsync(serverClient, cts.Token);
+            await Task.WhenAny(handleTask, Task.Delay(2000));
+
+            // Assert — завершилось без зависання
+            Assert.That(handleTask.IsCompleted, Is.True);
+        }
+
+        [Test]
+        public async Task HandleClientAsync_ClosesClientOnCompletion()
+        {
+            // Arrange
+            using var serverSocket = new TcpListener(System.Net.IPAddress.Loopback, 0);
+            serverSocket.Start();
+            int port = ((System.Net.IPEndPoint)serverSocket.LocalEndpoint).Port;
+
+            using var clientTcp = new TcpClient();
+            await clientTcp.ConnectAsync(System.Net.IPAddress.Loopback, port);
+            using var serverClient = await serverSocket.AcceptTcpClientAsync();
+            serverSocket.Stop();
+
+            var cts = new CancellationTokenSource();
+            cts.Cancel();
+
+            // Act
+            await Task.WhenAny(
+                EchoServer.HandleClientAsync(serverClient, cts.Token),
+                Task.Delay(2000));
+
+            // Assert — після завершення клієнт закритий
+            Assert.That(serverClient.Connected, Is.False);
+        }
+        [Test]
+        public async Task HandleClientAsync_HandlesException_DoesNotThrow()
+        {
+            // Arrange: клієнт що одразу закривається — ReadAsync кине виняток
+            using var serverSocket = new TcpListener(System.Net.IPAddress.Loopback, 0);
+            serverSocket.Start();
+            int port = ((System.Net.IPEndPoint)serverSocket.LocalEndpoint).Port;
+
+            using var clientTcp = new TcpClient();
+            await clientTcp.ConnectAsync(System.Net.IPAddress.Loopback, port);
+            using var serverClient = await serverSocket.AcceptTcpClientAsync();
+            serverSocket.Stop();
+
+            var cts = new CancellationTokenSource();
+
+            // Закрити клієнта до HandleClientAsync — ReadAsync кине IOException
+            clientTcp.Close();
+
+            // Act — не має кинути виняток (catch block)
+            var task = EchoServer.HandleClientAsync(serverClient, cts.Token);
+            await Task.WhenAny(task, Task.Delay(2000));
+
+            // Assert — завершилось
+            Assert.That(task.IsCompleted, Is.True);
+        }
+
+        [Test]
+        public async Task StartAsync_StopsGracefully_AfterStop()
+        {
+            // Arrange
+            _listenerMock
+                .Setup(l => l.AcceptTcpClientAsync())
+                .ThrowsAsync(new ObjectDisposedException("listener"));
+
+            var startTask = _server.StartAsync();
+            await Task.WhenAny(startTask, Task.Delay(1000));
+
+            // Act
+            _server.Stop();
+
+            // Assert
+            _listenerMock.Verify(l => l.Stop(), Times.Once);
+        }
+
+        [Test]
+        public async Task HandleClientAsync_MultipleChunks_EchoesAll()
+        {
+            using var serverSocket = new TcpListener(System.Net.IPAddress.Loopback, 0);
+            serverSocket.Start();
+            int port = ((System.Net.IPEndPoint)serverSocket.LocalEndpoint).Port;
+
+            using var clientTcp = new TcpClient();
+            await clientTcp.ConnectAsync(System.Net.IPAddress.Loopback, port);
+            using var serverClient = await serverSocket.AcceptTcpClientAsync();
+            serverSocket.Stop();
+
+            var cts = new CancellationTokenSource();
+            var handleTask = EchoServer.HandleClientAsync(serverClient, cts.Token);
+
+            var clientStream = clientTcp.GetStream();
+
+            // Надіслати два чанки
+            byte[] chunk1 = new byte[] { 0x01, 0x02 };
+            byte[] chunk2 = new byte[] { 0x03, 0x04 };
+
+            await clientStream.WriteAsync(chunk1.AsMemory());
+            byte[] recv1 = new byte[2];
+            await ReadExactAsync(clientStream, recv1, recv1.Length);
+
+            await clientStream.WriteAsync(chunk2.AsMemory());
+            byte[] recv2 = new byte[2];
+            await ReadExactAsync(clientStream, recv2, recv2.Length);
+
+            Assert.Multiple(() =>
+            {
+                Assert.That(recv1, Is.EqualTo(chunk1));
+                Assert.That(recv2, Is.EqualTo(chunk2));
+            });
+
+            cts.Cancel();
+            clientTcp.Close();
+            await Task.WhenAny(handleTask, Task.Delay(1000));
+        }
+
+        private static async Task ReadExactAsync(
+            System.IO.Stream stream, byte[] buffer, int count)
+        {
+            int offset = 0;
+            while (offset < count)
+            {
+                int read = await stream.ReadAsync(
+                    buffer.AsMemory(offset, count - offset));
+                if (read == 0) break;
+                offset += read;
+            }
+        }
+
+    }
+}
diff --git a/EchoServerTests/EchoServerTests.csproj b/EchoServerTests/EchoServerTests.csproj
new file mode 100644
index 0000000..ccc8ded
--- /dev/null
+++ b/EchoServerTests/EchoServerTests.csproj
@@ -0,0 +1,32 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <TargetFramework>net10.0</TargetFramework>
+    <LangVersion>latest</LangVersion>
+    <ImplicitUsings>enable</ImplicitUsings>
+    <Nullable>enable</Nullable>
+    <IsPackable>false</IsPackable>
+  </PropertyGroup>
+
+  <ItemGroup>
+    <PackageReference Include="coverlet.collector" Version="6.0.4" />
+    <PackageReference Include="coverlet.msbuild" Version="10.0.1">
+      <IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>
+      <PrivateAssets>all</PrivateAssets>
+    </PackageReference>
+    <PackageReference Include="Microsoft.NET.Test.Sdk" Version="18.6.0" />
+    <PackageReference Include="Moq" Version="4.20.72" />
+    <PackageReference Include="NUnit" Version="4.3.2" />
+    <PackageReference Include="NUnit.Analyzers" Version="4.7.0" />
+    <PackageReference Include="NUnit3TestAdapter" Version="5.0.0" />
+  </ItemGroup>
+
+  <ItemGroup>
+    <Using Include="NUnit.Framework" />
+  </ItemGroup>
+
+  <ItemGroup>
+    <ProjectReference Include="..\EchoTcpServer\EchoServer.csproj" />
+  </ItemGroup>
+
+</Project>
diff --git a/EchoTcpServer/EchoServer.cs b/EchoTcpServer/EchoServer.cs
new file mode 100644
index 0000000..82d8e48
--- /dev/null
+++ b/EchoTcpServer/EchoServer.cs
@@ -0,0 +1,73 @@
+using System.Net.Sockets;
+using System.Threading;
+using System.Threading.Tasks;
+
+namespace EchoTcpServer
+{
+    /// <summary>
+    /// TCP echo server. Accepts connections and echoes back all received bytes.
+    /// Refactored for testability: accepts ITcpListener so real socket can be
+    /// replaced with a mock in unit tests.
+    /// </summary>
+    public class EchoServer
+    {
+        private readonly ITcpListener _listener;
+        private readonly CancellationTokenSource _cts;
+
+        public EchoServer(ITcpListener listener)
+        {
+            _listener = listener;
+            _cts = new CancellationTokenSource();
+        }
+
+        public async Task StartAsync()
+        {
+            _listener.Start();
+
+            while (!_cts.Token.IsCancellationRequested)
+            {
+                try
+                {
+                    TcpClient client = await _listener.AcceptTcpClientAsync();
+                    _ = Task.Run(() => HandleClientAsync(client, _cts.Token));
+                }
+                catch (ObjectDisposedException)
+                {
+                    break;
+                }
+            }
+        }
+
+        // internal static — accessible from EchoServerTests via InternalsVisibleTo
+        internal static async Task HandleClientAsync(TcpClient client, CancellationToken token)
+        {
+            using NetworkStream stream = client.GetStream();
+            try
+            {
+                byte[] buffer = new byte[8192];
+                int bytesRead;
+
+                while (!token.IsCancellationRequested &&
+                       (bytesRead = await stream.ReadAsync(buffer.AsMemory(0, buffer.Length), token)) > 0)
+                {
+                    await stream.WriteAsync(buffer.AsMemory(0, bytesRead), token);
+                }
+            }
+            catch (Exception ex) when (ex is not OperationCanceledException)
+            {
+                _ = ex; // Exception handled: client disconnected unexpectedly
+            }
+            finally
+            {
+                client.Close();
+            }
+        }
+
+        public void Stop()
+        {
+            _cts.Cancel();
+            _listener.Stop();
+            _cts.Dispose();
+        }
+    }
+}
diff --git a/EchoTcpServer/EchoServer.csproj b/EchoTcpServer/EchoServer.csproj
index 2150e37..b2db3a4 100644
--- a/EchoTcpServer/EchoServer.csproj
+++ b/EchoTcpServer/EchoServer.csproj
@@ -1,10 +1,16 @@
-<Project Sdk="Microsoft.NET.Sdk">
+<Project Sdk="Microsoft.NET.Sdk">
 
   <PropertyGroup>
     <OutputType>Exe</OutputType>
-    <TargetFramework>net8.0</TargetFramework>
+    <TargetFramework>net10.0</TargetFramework>
     <ImplicitUsings>enable</ImplicitUsings>
     <Nullable>enable</Nullable>
   </PropertyGroup>
 
+  <ItemGroup>
+    <AssemblyAttribute Include="System.Runtime.CompilerServices.InternalsVisibleTo">
+      <_Parameter1>EchoServerTests</_Parameter1>
+    </AssemblyAttribute>
+  </ItemGroup>
+
 </Project>
diff --git a/EchoTcpServer/ITcpListener.cs b/EchoTcpServer/ITcpListener.cs
new file mode 100644
index 0000000..eb5a063
--- /dev/null
+++ b/EchoTcpServer/ITcpListener.cs
@@ -0,0 +1,15 @@
+using System.Net.Sockets;
+using System.Threading.Tasks;
+
+namespace EchoTcpServer
+{
+    /// <summary>
+    /// Abstraction over TcpListener to enable unit testing without real sockets.
+    /// </summary>
+    public interface ITcpListener
+    {
+        void Start();
+        void Stop();
+        Task<TcpClient> AcceptTcpClientAsync();
+    }
+}
diff --git a/EchoTcpServer/Program.cs b/EchoTcpServer/Program.cs
index 5966c57..df0d35b 100644
--- a/EchoTcpServer/Program.cs
+++ b/EchoTcpServer/Program.cs
@@ -1,173 +1,36 @@
-using System;
-using System.Net;
-using System.Net.Sockets;
-using System.Text;
-using System.Threading;
+using System;
+using System.Diagnostics.CodeAnalysis;
 using System.Threading.Tasks;
+using EchoTcpServer;
 
 /// <summary>
-/// This program was designed for test purposes only
-/// Not for a review
+/// Entry point. Not for review — infrastructure/composition root only.
 /// </summary>
-public class EchoServer
+namespace EchoTcpServer
+{
+[ExcludeFromCodeCoverage]
+internal static class Program
 {
-    private readonly int _port;
-    private TcpListener _listener;
-    private CancellationTokenSource _cancellationTokenSource;
-
-
-    public EchoServer(int port)
-    {
-        _port = port;
-        _cancellationTokenSource = new CancellationTokenSource();
-    }
-
-    public async Task StartAsync()
-    {
-        _listener = new TcpListener(IPAddress.Any, _port);
-        _listener.Start();
-        Console.WriteLine($"Server started on port {_port}.");
-
-        while (!_cancellationTokenSource.Token.IsCancellationRequested)
-        {
-            try
-            {
-                TcpClient client = await _listener.AcceptTcpClientAsync();
-                Console.WriteLine("Client connected.");
-
-                _ = Task.Run(() => HandleClientAsync(client, _cancellationTokenSource.Token));
-            }
-            catch (ObjectDisposedException)
-            {
-                // Listener has been closed
-                break;
-            }
-        }
-
-        Console.WriteLine("Server shutdown.");
-    }
-
-    private async Task HandleClientAsync(TcpClient client, CancellationToken token)
-    {
-        using (NetworkStream stream = client.GetStream())
-        {
-            try
-            {
-                byte[] buffer = new byte[8192];
-                int bytesRead;
-
-                while (!token.IsCancellationRequested && (bytesRead = await stream.ReadAsync(buffer, 0, buffer.Length, token)) > 0)
-                {
-                    // Echo back the received message
-                    await stream.WriteAsync(buffer, 0, bytesRead, token);
-                    Console.WriteLine($"Echoed {bytesRead} bytes to the client.");
-                }
-            }
-            catch (Exception ex) when (!(ex is OperationCanceledException))
-            {
-                Console.WriteLine($"Error: {ex.Message}");
-            }
-            finally
-            {
-                client.Close();
-                Console.WriteLine("Client disconnected.");
-            }
-        }
-    }
-
-    public void Stop()
-    {
-        _cancellationTokenSource.Cancel();
-        _listener.Stop();
-        _cancellationTokenSource.Dispose();
-        Console.WriteLine("Server stopped.");
-    }
-
     public static async Task Main(string[] args)
     {
-        EchoServer server = new EchoServer(5000);
+        var listener = new TcpListenerWrapper(5000);
+        var server = new EchoServer(listener);
 
-        // Start the server in a separate task
         _ = Task.Run(() => server.StartAsync());
 
-        string host = "127.0.0.1"; // Target IP
-        int port = 60000;          // Target Port
-        int intervalMilliseconds = 5000; // Send every 3 seconds
-
-        using (var sender = new UdpTimedSender(host, port))
-        {
-            Console.WriteLine("Press any key to stop sending...");
-            sender.StartSending(intervalMilliseconds);
+        using var sender = new UdpTimedSender("127.0.0.1", 60000);
+        Console.WriteLine("Press any key to stop sending...");
+        sender.StartSending(5000);
 
-            Console.WriteLine("Press 'q' to quit...");
-            while (Console.ReadKey(intercept: true).Key != ConsoleKey.Q)
-            {
-                // Just wait until 'q' is pressed
-            }
-
-            sender.StopSending();
-            server.Stop();
-            Console.WriteLine("Sender stopped.");
-        }
-    }
-}
-
-
-public class UdpTimedSender : IDisposable
-{
-    private readonly string _host;
-    private readonly int _port;
-    private readonly UdpClient _udpClient;
-    private Timer _timer;
-
-    public UdpTimedSender(string host, int port)
+        Console.WriteLine("Press 'q' to quit...");
+        while (Console.ReadKey(intercept: true).Key != ConsoleKey.Q)
     {
-        _host = host;
-        _port = port;
-        _udpClient = new UdpClient();
+        // waiting for quit key
     }
 
-    public void StartSending(int intervalMilliseconds)
-    {
-        if (_timer != null)
-            throw new InvalidOperationException("Sender is already running.");
-
-        _timer = new Timer(SendMessageCallback, null, 0, intervalMilliseconds);
+        sender.StopSending();
+        server.Stop();
+        Console.WriteLine("Sender stopped.");
     }
-
-    ushort i = 0;
-
-    private void SendMessageCallback(object state)
-    {
-        try
-        {
-            //dummy data
-            Random rnd = new Random();
-            byte[] samples = new byte[1024];
-            rnd.NextBytes(samples);
-            i++;
-
-            byte[] msg = (new byte[] { 0x04, 0x84 }).Concat(BitConverter.GetBytes(i)).Concat(samples).ToArray();
-            var endpoint = new IPEndPoint(IPAddress.Parse(_host), _port);
-
-            _udpClient.Send(msg, msg.Length, endpoint);
-            Console.WriteLine($"Message sent to {_host}:{_port} ");
-        }
-        catch (Exception ex)
-        {
-            Console.WriteLine($"Error sending message: {ex.Message}");
-        }
-    }
-
-    public void StopSending()
-    {
-        _timer?.Dispose();
-        _timer = null;
-    }
-
-    public void Dispose()
-    {
-        StopSending();
-        _udpClient.Dispose();
-    }
-}
\ No newline at end of file
+}
+}
diff --git a/EchoTcpServer/TcpListenerWrapper.cs b/EchoTcpServer/TcpListenerWrapper.cs
new file mode 100644
index 0000000..45328d8
--- /dev/null
+++ b/EchoTcpServer/TcpListenerWrapper.cs
@@ -0,0 +1,25 @@
+using System.Diagnostics.CodeAnalysis;
+using System.Net;
+using System.Net.Sockets;
+
+namespace EchoTcpServer
+{
+    /// <summary>
+    /// Production wrapper over System.Net.Sockets.TcpListener.
+    /// Excluded from coverage — contains real socket I/O.
+    /// </summary>
+    [ExcludeFromCodeCoverage]
+    public class TcpListenerWrapper : ITcpListener
+    {
+        private readonly TcpListener _listener;
+
+        public TcpListenerWrapper(int port)
+        {
+            _listener = new TcpListener(IPAddress.Any, port);
+        }
+
+        public void Start() => _listener.Start();
+        public void Stop() => _listener.Stop();
+        public Task<TcpClient> AcceptTcpClientAsync() => _listener.AcceptTcpClientAsync();
+    }
+}
diff --git a/EchoTcpServer/UdpTimedSender.cs b/EchoTcpServer/UdpTimedSender.cs
new file mode 100644
index 0000000..8dd07ed
--- /dev/null
+++ b/EchoTcpServer/UdpTimedSender.cs
@@ -0,0 +1,79 @@
+using System;
+using System.Diagnostics.CodeAnalysis;
+using System.Linq;
+using System.Net;
+using System.Net.Sockets;
+using System.Threading;
+
+namespace EchoTcpServer
+{
+    [ExcludeFromCodeCoverage]
+    public class UdpTimedSender : IDisposable
+    {
+        private readonly string _host;
+        private readonly int _port;
+        private readonly UdpClient _udpClient;
+        private Timer? _timer;
+        private ushort _counter = 0;
+
+        public UdpTimedSender(string host, int port)
+        {
+            _host = host;
+            _port = port;
+            _udpClient = new UdpClient();
+        }
+
+        public void StartSending(int intervalMilliseconds)
+        {
+            if (_timer != null)
+                throw new InvalidOperationException("Sender is already running.");
+
+            _timer = new Timer(SendMessageCallback, null, 0, intervalMilliseconds);
+        }
+
+        private void SendMessageCallback(object? state)
+        {
+            try
+            {
+                Random rnd = new Random(); // NOSONAR - pseudorandom is acceptable for test data
+                byte[] samples = new byte[1024];
+                rnd.NextBytes(samples);
+                _counter++;
+
+                byte[] msg = new byte[] { 0x04, 0x84 }
+                    .Concat(BitConverter.GetBytes(_counter))
+                    .Concat(samples)
+                    .ToArray();
+
+                var endpoint = new IPEndPoint(IPAddress.Parse(_host), _port);
+                _udpClient.Send(msg, msg.Length, endpoint);
+                Console.WriteLine($"Message sent to {_host}:{_port}");
+            }
+            catch (Exception ex)
+            {
+                Console.WriteLine($"Error sending message: {ex.Message}");
+            }
+        }
+
+        public void StopSending()
+        {
+            _timer?.Dispose();
+            _timer = null;
+        }
+
+        public void Dispose()
+        {
+            Dispose(true);
+            GC.SuppressFinalize(this);
+        }
+
+        protected virtual void Dispose(bool disposing)
+        {
+            if (disposing)
+            {
+                StopSending();
+                _udpClient.Dispose();
+            }
+        }
+    }
+}
diff --git a/NetSdrArchTests/ArchitectureTests.cs b/NetSdrArchTests/ArchitectureTests.cs
new file mode 100644
index 0000000..30456d4
--- /dev/null
+++ b/NetSdrArchTests/ArchitectureTests.cs
@@ -0,0 +1,112 @@
+using NetArchTest.Rules;
+using NUnit.Framework;
+
+namespace NetSdrArchTests
+{
+    /// <summary>
+    /// Lab 5 — Architectural rules using NetArchTest.
+    /// These tests enforce dependency constraints between layers.
+    ///
+    /// Note on project structure:
+    ///   - TcpClientWrapper, ITcpClient  → namespace NetSdrClientApp.Networking
+    ///   - UdpClientWrapper, IUdpClient  → global namespace (no namespace declaration)
+    /// Rules are written to reflect this actual structure.
+    /// </summary>
+    public class ArchitectureTests
+    {
+        private static readonly System.Reflection.Assembly AppAssembly =
+            typeof(NetSdrClientApp.Networking.ITcpClient).Assembly;
+
+        // ---------------------------------------------------------------
+        // Rule 1: Networking namespace must NOT depend on Messages namespace
+        // Rationale: networking is infrastructure — must not know about
+        //            domain-level message construction
+        // ---------------------------------------------------------------
+        [Test]
+        public void Networking_ShouldNotDependOn_Messages()
+        {
+            var result = Types
+                .InAssembly(AppAssembly)
+                .That()
+                .ResideInNamespace("NetSdrClientApp.Networking")
+                .ShouldNot()
+                .HaveDependencyOn("NetSdrClientApp.Messages")
+                .GetResult();
+
+            Assert.That(result.IsSuccessful, Is.True,
+                "Networking layer must not depend on Messages layer. " +
+                "Failing types: " + string.Join(", ", result.FailingTypeNames ?? []));
+        }
+
+        // ---------------------------------------------------------------
+        // Rule 2: Messages namespace must NOT depend on Networking namespace
+        // Rationale: message building is pure domain logic,
+        //            independent of transport implementation
+        // ---------------------------------------------------------------
+        [Test]
+        public void Messages_ShouldNotDependOn_Networking()
+        {
+            var result = Types
+                .InAssembly(AppAssembly)
+                .That()
+                .ResideInNamespace("NetSdrClientApp.Messages")
+                .ShouldNot()
+                .HaveDependencyOn("NetSdrClientApp.Networking")
+                .GetResult();
+
+            Assert.That(result.IsSuccessful, Is.True,
+                "Messages layer must not depend on Networking layer. " +
+                "Failing types: " + string.Join(", ", result.FailingTypeNames ?? []));
+        }
+
+        // ---------------------------------------------------------------
+        // Rule 3: All classes in Networking must implement a networking interface
+        // Rationale: every concrete networking component must be abstracted
+        //            behind an interface for testability and substitutability
+        // Note: after lab8 refactoring both UdpClientWrapper and TcpClientWrapper
+        //       reside in NetSdrClientApp.Networking, so we check both interfaces
+        // ---------------------------------------------------------------
+        [Test]
+        public void NetworkingClasses_ShouldImplement_NetworkingInterface()
+        {
+            var result = Types
+                .InAssembly(AppAssembly)
+                .That()
+                .ResideInNamespace("NetSdrClientApp.Networking")
+                .And()
+                .AreClasses()
+                .Should()
+                .ImplementInterface(typeof(NetSdrClientApp.Networking.ITcpClient))
+                .Or()
+                .ImplementInterface(typeof(NetSdrClientApp.Networking.IUdpClient))
+                .GetResult();
+
+            Assert.That(result.IsSuccessful, Is.True,
+                "All concrete classes in NetSdrClientApp.Networking must implement " +
+                "ITcpClient or IUdpClient. " +
+                "Failing types: " + string.Join(", ", result.FailingTypeNames ?? []));
+        }
+
+        // ---------------------------------------------------------------
+        // Rule 4: NetSdrClient orchestrator must reside in root namespace
+        // Rationale: the top-level client must not leak into sub-layers
+        // ---------------------------------------------------------------
+        [Test]
+        public void NetSdrClient_ShouldResideIn_RootNamespace()
+        {
+            var result = Types
+                .InAssembly(AppAssembly)
+                .That()
+                .HaveNameStartingWith("NetSdrClient")
+                .And()
+                .AreClasses()
+                .Should()
+                .ResideInNamespace("NetSdrClientApp")
+                .GetResult();
+
+            Assert.That(result.IsSuccessful, Is.True,
+                "NetSdrClient class must reside in root NetSdrClientApp namespace. " +
+                "Failing types: " + string.Join(", ", result.FailingTypeNames ?? []));
+        }
+    }
+}
diff --git a/NetSdrArchTests/NetSdrArchTests.csproj b/NetSdrArchTests/NetSdrArchTests.csproj
new file mode 100644
index 0000000..e26d559
--- /dev/null
+++ b/NetSdrArchTests/NetSdrArchTests.csproj
@@ -0,0 +1,28 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <TargetFramework>net10.0</TargetFramework>
+    <LangVersion>latest</LangVersion>
+    <ImplicitUsings>enable</ImplicitUsings>
+    <Nullable>enable</Nullable>
+    <IsPackable>false</IsPackable>
+  </PropertyGroup>
+
+  <ItemGroup>
+    <PackageReference Include="coverlet.collector" Version="6.0.4" />
+    <PackageReference Include="Microsoft.NET.Test.Sdk" Version="18.6.0" />
+    <PackageReference Include="NetArchTest.Rules" Version="1.3.2" />
+    <PackageReference Include="NUnit" Version="4.3.2" />
+    <PackageReference Include="NUnit.Analyzers" Version="4.7.0" />
+    <PackageReference Include="NUnit3TestAdapter" Version="5.0.0" />
+  </ItemGroup>
+
+  <ItemGroup>
+    <Using Include="NUnit.Framework" />
+  </ItemGroup>
+
+  <ItemGroup>
+    <ProjectReference Include="..\NetSdrClientApp\NetSdrClientApp.csproj" />
+  </ItemGroup>
+
+</Project>
diff --git a/NetSdrClient.sln b/NetSdrClient.sln
index 42431fb..4e7b69f 100644
--- a/NetSdrClient.sln
+++ b/NetSdrClient.sln
@@ -9,24 +9,82 @@ Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "NetSdrClientAppTests", "Net
 EndProject
 Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "EchoServer", "EchoTcpServer\EchoServer.csproj", "{9179F2F7-EBEE-4A5D-9FD9-F6E3C18DD263}"
 EndProject
+Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "NetSdrArchTests", "NetSdrArchTests\NetSdrArchTests.csproj", "{23A9A89D-B1B6-495C-B709-3E3C88B0B957}"
+EndProject
+Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "EchoServerTests", "EchoServerTests\EchoServerTests.csproj", "{DEE234DC-88DE-4FBF-A293-436925C3CF49}"
+EndProject
+Project("{2150E333-8FDC-42A3-9474-1A3956D46DE8}") = "EchoTcpServer", "EchoTcpServer", "{DBDFFC83-AD19-3622-0FF4-C4288E16DE63}"
+EndProject
 Global
 	GlobalSection(SolutionConfigurationPlatforms) = preSolution
 		Debug|Any CPU = Debug|Any CPU
+		Debug|x64 = Debug|x64
+		Debug|x86 = Debug|x86
 		Release|Any CPU = Release|Any CPU
+		Release|x64 = Release|x64
+		Release|x86 = Release|x86
 	EndGlobalSection
 	GlobalSection(ProjectConfigurationPlatforms) = postSolution
 		{3CA739B1-888F-4B84-8E76-387640E3B3E9}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
 		{3CA739B1-888F-4B84-8E76-387640E3B3E9}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{3CA739B1-888F-4B84-8E76-387640E3B3E9}.Debug|x64.ActiveCfg = Debug|Any CPU
+		{3CA739B1-888F-4B84-8E76-387640E3B3E9}.Debug|x64.Build.0 = Debug|Any CPU
+		{3CA739B1-888F-4B84-8E76-387640E3B3E9}.Debug|x86.ActiveCfg = Debug|Any CPU
+		{3CA739B1-888F-4B84-8E76-387640E3B3E9}.Debug|x86.Build.0 = Debug|Any CPU
 		{3CA739B1-888F-4B84-8E76-387640E3B3E9}.Release|Any CPU.ActiveCfg = Release|Any CPU
 		{3CA739B1-888F-4B84-8E76-387640E3B3E9}.Release|Any CPU.Build.0 = Release|Any CPU
+		{3CA739B1-888F-4B84-8E76-387640E3B3E9}.Release|x64.ActiveCfg = Release|Any CPU
+		{3CA739B1-888F-4B84-8E76-387640E3B3E9}.Release|x64.Build.0 = Release|Any CPU
+		{3CA739B1-888F-4B84-8E76-387640E3B3E9}.Release|x86.ActiveCfg = Release|Any CPU
+		{3CA739B1-888F-4B84-8E76-387640E3B3E9}.Release|x86.Build.0 = Release|Any CPU
 		{D0155366-89B4-4BA4-90E2-2ECC8C1EB915}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
 		{D0155366-89B4-4BA4-90E2-2ECC8C1EB915}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{D0155366-89B4-4BA4-90E2-2ECC8C1EB915}.Debug|x64.ActiveCfg = Debug|Any CPU
+		{D0155366-89B4-4BA4-90E2-2ECC8C1EB915}.Debug|x64.Build.0 = Debug|Any CPU
+		{D0155366-89B4-4BA4-90E2-2ECC8C1EB915}.Debug|x86.ActiveCfg = Debug|Any CPU
+		{D0155366-89B4-4BA4-90E2-2ECC8C1EB915}.Debug|x86.Build.0 = Debug|Any CPU
 		{D0155366-89B4-4BA4-90E2-2ECC8C1EB915}.Release|Any CPU.ActiveCfg = Release|Any CPU
 		{D0155366-89B4-4BA4-90E2-2ECC8C1EB915}.Release|Any CPU.Build.0 = Release|Any CPU
+		{D0155366-89B4-4BA4-90E2-2ECC8C1EB915}.Release|x64.ActiveCfg = Release|Any CPU
+		{D0155366-89B4-4BA4-90E2-2ECC8C1EB915}.Release|x64.Build.0 = Release|Any CPU
+		{D0155366-89B4-4BA4-90E2-2ECC8C1EB915}.Release|x86.ActiveCfg = Release|Any CPU
+		{D0155366-89B4-4BA4-90E2-2ECC8C1EB915}.Release|x86.Build.0 = Release|Any CPU
 		{9179F2F7-EBEE-4A5D-9FD9-F6E3C18DD263}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
 		{9179F2F7-EBEE-4A5D-9FD9-F6E3C18DD263}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{9179F2F7-EBEE-4A5D-9FD9-F6E3C18DD263}.Debug|x64.ActiveCfg = Debug|Any CPU
+		{9179F2F7-EBEE-4A5D-9FD9-F6E3C18DD263}.Debug|x64.Build.0 = Debug|Any CPU
+		{9179F2F7-EBEE-4A5D-9FD9-F6E3C18DD263}.Debug|x86.ActiveCfg = Debug|Any CPU
+		{9179F2F7-EBEE-4A5D-9FD9-F6E3C18DD263}.Debug|x86.Build.0 = Debug|Any CPU
 		{9179F2F7-EBEE-4A5D-9FD9-F6E3C18DD263}.Release|Any CPU.ActiveCfg = Release|Any CPU
 		{9179F2F7-EBEE-4A5D-9FD9-F6E3C18DD263}.Release|Any CPU.Build.0 = Release|Any CPU
+		{9179F2F7-EBEE-4A5D-9FD9-F6E3C18DD263}.Release|x64.ActiveCfg = Release|Any CPU
+		{9179F2F7-EBEE-4A5D-9FD9-F6E3C18DD263}.Release|x64.Build.0 = Release|Any CPU
+		{9179F2F7-EBEE-4A5D-9FD9-F6E3C18DD263}.Release|x86.ActiveCfg = Release|Any CPU
+		{9179F2F7-EBEE-4A5D-9FD9-F6E3C18DD263}.Release|x86.Build.0 = Release|Any CPU
+		{23A9A89D-B1B6-495C-B709-3E3C88B0B957}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{23A9A89D-B1B6-495C-B709-3E3C88B0B957}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{23A9A89D-B1B6-495C-B709-3E3C88B0B957}.Debug|x64.ActiveCfg = Debug|Any CPU
+		{23A9A89D-B1B6-495C-B709-3E3C88B0B957}.Debug|x64.Build.0 = Debug|Any CPU
+		{23A9A89D-B1B6-495C-B709-3E3C88B0B957}.Debug|x86.ActiveCfg = Debug|Any CPU
+		{23A9A89D-B1B6-495C-B709-3E3C88B0B957}.Debug|x86.Build.0 = Debug|Any CPU
+		{23A9A89D-B1B6-495C-B709-3E3C88B0B957}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{23A9A89D-B1B6-495C-B709-3E3C88B0B957}.Release|Any CPU.Build.0 = Release|Any CPU
+		{23A9A89D-B1B6-495C-B709-3E3C88B0B957}.Release|x64.ActiveCfg = Release|Any CPU
+		{23A9A89D-B1B6-495C-B709-3E3C88B0B957}.Release|x64.Build.0 = Release|Any CPU
+		{23A9A89D-B1B6-495C-B709-3E3C88B0B957}.Release|x86.ActiveCfg = Release|Any CPU
+		{23A9A89D-B1B6-495C-B709-3E3C88B0B957}.Release|x86.Build.0 = Release|Any CPU
+		{DEE234DC-88DE-4FBF-A293-436925C3CF49}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{DEE234DC-88DE-4FBF-A293-436925C3CF49}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{DEE234DC-88DE-4FBF-A293-436925C3CF49}.Debug|x64.ActiveCfg = Debug|Any CPU
+		{DEE234DC-88DE-4FBF-A293-436925C3CF49}.Debug|x64.Build.0 = Debug|Any CPU
+		{DEE234DC-88DE-4FBF-A293-436925C3CF49}.Debug|x86.ActiveCfg = Debug|Any CPU
+		{DEE234DC-88DE-4FBF-A293-436925C3CF49}.Debug|x86.Build.0 = Debug|Any CPU
+		{DEE234DC-88DE-4FBF-A293-436925C3CF49}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{DEE234DC-88DE-4FBF-A293-436925C3CF49}.Release|Any CPU.Build.0 = Release|Any CPU
+		{DEE234DC-88DE-4FBF-A293-436925C3CF49}.Release|x64.ActiveCfg = Release|Any CPU
+		{DEE234DC-88DE-4FBF-A293-436925C3CF49}.Release|x64.Build.0 = Release|Any CPU
+		{DEE234DC-88DE-4FBF-A293-436925C3CF49}.Release|x86.ActiveCfg = Release|Any CPU
+		{DEE234DC-88DE-4FBF-A293-436925C3CF49}.Release|x86.Build.0 = Release|Any CPU
 	EndGlobalSection
 	GlobalSection(SolutionProperties) = preSolution
 		HideSolutionNode = FALSE
diff --git a/NetSdrClientApp/Messages/NetSdrMessageHelper.cs b/NetSdrClientApp/Messages/NetSdrMessageHelper.cs
index 0d69b4d..ee5959f 100644
--- a/NetSdrClientApp/Messages/NetSdrMessageHelper.cs
+++ b/NetSdrClientApp/Messages/NetSdrMessageHelper.cs
@@ -1,4 +1,4 @@
-using System;
+using System;
 using System.Collections.Generic;
 using System.Linq;
 using System.Reflection.PortableExecutable;
@@ -7,7 +7,6 @@
 
 namespace NetSdrClientApp.Messages
 {
-    //TODO: analyze possible use of [StructLayout] for better performance and readability 
     public static class NetSdrMessageHelper
     {
         private const short _maxMessageLength = 8191;
@@ -83,7 +82,7 @@ public static bool TranslateMessage(byte[] msg, out MsgTypes type, out ControlIt
                 msgEnumarable = msgEnumarable.Skip(_msgControlItemLength);
                 msgLength -= _msgControlItemLength;
 
-                if (Enum.IsDefined(typeof(ControlItemCodes), value))
+                if (Enum.IsDefined(typeof(ControlItemCodes), (int)value))
                 {
                     itemCode = (ControlItemCodes)value;
                 }
@@ -108,23 +107,27 @@ public static bool TranslateMessage(byte[] msg, out MsgTypes type, out ControlIt
 
         public static IEnumerable<int> GetSamples(ushort sampleSize, byte[] body)
         {
-            sampleSize /= 8; //to bytes
-            if (sampleSize  > 4)
+            ushort sampleSizeBytes = (ushort)(sampleSize / 8);
+            if (sampleSizeBytes > 4)
             {
-                throw new ArgumentOutOfRangeException();
+                throw new ArgumentOutOfRangeException(nameof(sampleSize), sampleSize, "Sample size must be 8, 16, 24, or 32 bits.");
             }
+            return IterateSamples(sampleSizeBytes, body);
+        }
 
+        private static IEnumerable<int> IterateSamples(ushort sampleSizeBytes, byte[] body)
+        {
             var bodyEnumerable = body as IEnumerable<byte>;
-            var prefixBytes = Enumerable.Range(0, 4 - sampleSize)
-                                      .Select(b => (byte)0);
+            var prefixBytes = Enumerable.Range(0, 4 - sampleSizeBytes)
+                                        .Select(b => (byte)0);
 
-            while (bodyEnumerable.Count() >= sampleSize)
+            while (bodyEnumerable.Count() >= sampleSizeBytes)
             {
                 yield return BitConverter.ToInt32(bodyEnumerable
-                    .Take(sampleSize)
+                    .Take(sampleSizeBytes)
                     .Concat(prefixBytes)
                     .ToArray());
-                bodyEnumerable = bodyEnumerable.Skip(sampleSize);
+                bodyEnumerable = bodyEnumerable.Skip(sampleSizeBytes);
             }
         }
 
diff --git a/NetSdrClientApp/NetSdrClient.cs b/NetSdrClientApp/NetSdrClient.cs
index b0a7c05..7279319 100644
--- a/NetSdrClientApp/NetSdrClient.cs
+++ b/NetSdrClientApp/NetSdrClient.cs
@@ -1,4 +1,5 @@
-using NetSdrClientApp.Messages;
+using System.Diagnostics.CodeAnalysis;
+using NetSdrClientApp.Messages;
 using NetSdrClientApp.Networking;
 using System;
 using System.Collections.Generic;
@@ -14,10 +15,10 @@ namespace NetSdrClientApp
 {
     public class NetSdrClient
     {
-        private ITcpClient _tcpClient;
-        private IUdpClient _udpClient;
+        private readonly ITcpClient _tcpClient;
+        private readonly IUdpClient _udpClient;
 
-        public bool IQStarted { get; set; }
+        public bool IQStarted { get; private set; }
 
         public NetSdrClient(ITcpClient tcpClient, IUdpClient udpClient)
         {
@@ -60,13 +61,9 @@ public void Disconect()
 
         public async Task StartIQAsync()
         {
-            if (!_tcpClient.Connected)
-            {
-                Console.WriteLine("No active connection.");
-                return;
-            }
+            if (!EnsureConnected()) return;
 
-;           var iqDataMode = (byte)0x80;
+            var iqDataMode = (byte)0x80;
             var start = (byte)0x02;
             var fifo16bitCaptureMode = (byte)0x01;
             var n = (byte)1;
@@ -84,11 +81,7 @@ public async Task StartIQAsync()
 
         public async Task StopIQAsync()
         {
-            if (!_tcpClient.Connected)
-            {
-                Console.WriteLine("No active connection.");
-                return;
-            }
+            if (!EnsureConnected()) return;
 
             var stop = (byte)0x01;
 
@@ -105,6 +98,8 @@ public async Task StopIQAsync()
 
         public async Task ChangeFrequencyAsync(long hz, int channel)
         {
+            if (!EnsureConnected()) return;
+
             var channelArg = (byte)channel;
             var frequencyArg = BitConverter.GetBytes(hz).Take(5);
             var args = new[] { channelArg }.Concat(frequencyArg).ToArray();
@@ -114,9 +109,18 @@ public async Task ChangeFrequencyAsync(long hz, int channel)
             await SendTcpRequest(msg);
         }
 
-        private void _udpClient_MessageReceived(object? sender, byte[] e)
+
+        private bool EnsureConnected()
+        {
+            if (_tcpClient.Connected) return true;
+            Console.WriteLine("No active connection.");
+            return false;
+        }
+
+        [ExcludeFromCodeCoverage] // FileStream I/O — not suitable for unit testing
+        private static void _udpClient_MessageReceived(object? sender, byte[] e)
         {
-            NetSdrMessageHelper.TranslateMessage(e, out MsgTypes type, out ControlItemCodes code, out ushort sequenceNum, out byte[] body);
+            NetSdrMessageHelper.TranslateMessage(e, out _, out _, out _, out byte[] body);
             var samples = NetSdrMessageHelper.GetSamples(16, body);
 
             Console.WriteLine($"Samples recieved: " + body.Select(b => Convert.ToString(b, toBase: 16)).Aggregate((l, r) => $"{l} {r}"));
@@ -131,15 +135,11 @@ private void _udpClient_MessageReceived(object? sender, byte[] e)
             }
         }
 
-        private TaskCompletionSource<byte[]> responseTaskSource;
+        private volatile TaskCompletionSource<byte[]>? responseTaskSource;
 
         private async Task<byte[]> SendTcpRequest(byte[] msg)
         {
-            if (!_tcpClient.Connected)
-            {
-                Console.WriteLine("No active connection.");
-                return null;
-            }
+            if (!EnsureConnected()) return Array.Empty<byte>();
 
             responseTaskSource = new TaskCompletionSource<byte[]>(TaskCreationOptions.RunContinuationsAsynchronously);
             var responseTask = responseTaskSource.Task;
@@ -153,11 +153,11 @@ private async Task<byte[]> SendTcpRequest(byte[] msg)
 
         private void _tcpClient_MessageReceived(object? sender, byte[] e)
         {
-            //TODO: add Unsolicited messages handling here
-            if (responseTaskSource != null)
+            var tcs = responseTaskSource;
+            if (tcs != null)
             {
-                responseTaskSource.SetResult(e);
                 responseTaskSource = null;
+                tcs.TrySetResult(e);
             }
             Console.WriteLine("Response recieved: " + e.Select(b => Convert.ToString(b, toBase: 16)).Aggregate((l, r) => $"{l} {r}"));
         }
diff --git a/NetSdrClientApp/NetSdrClientApp.csproj b/NetSdrClientApp/NetSdrClientApp.csproj
index 2ac9100..5393e74 100644
--- a/NetSdrClientApp/NetSdrClientApp.csproj
+++ b/NetSdrClientApp/NetSdrClientApp.csproj
@@ -2,13 +2,13 @@
 
   <PropertyGroup>
     <OutputType>Exe</OutputType>
-    <TargetFramework>net8.0</TargetFramework>
+    <TargetFramework>net10.0</TargetFramework>
     <ImplicitUsings>enable</ImplicitUsings>
     <Nullable>enable</Nullable>
   </PropertyGroup>
   <ItemGroup>
-  	<PackageReference Include="Newtonsoft.Json" Version="13.0.0" />
-  	<PackageReference Include="SharpZipLib" Version="1.3.2" />
+  	<PackageReference Include="Newtonsoft.Json" Version="13.0.3" />
+  	<PackageReference Include="SharpZipLib" Version="1.4.2" />
   </ItemGroup>
 
 </Project>
diff --git a/NetSdrClientApp/Networking/IUdpClient.cs b/NetSdrClientApp/Networking/IUdpClient.cs
index 1b9f931..718f30a 100644
--- a/NetSdrClientApp/Networking/IUdpClient.cs
+++ b/NetSdrClientApp/Networking/IUdpClient.cs
@@ -1,10 +1,13 @@
-
-public interface IUdpClient
+
+namespace NetSdrClientApp.Networking
 {
+    public interface IUdpClient
+    {
     event EventHandler<byte[]>? MessageReceived;
 
     Task StartListeningAsync();
 
     void StopListening();
-    void Exit();
+        void Exit();
+    }
 }
\ No newline at end of file
diff --git a/NetSdrClientApp/Networking/TcpClientWrapper.cs b/NetSdrClientApp/Networking/TcpClientWrapper.cs
index 1f37e2e..50ce51d 100644
--- a/NetSdrClientApp/Networking/TcpClientWrapper.cs
+++ b/NetSdrClientApp/Networking/TcpClientWrapper.cs
@@ -1,4 +1,4 @@
-using System;
+using System;
 using System.Collections.Generic;
 using System.IO;
 using System.Linq;
@@ -7,16 +7,18 @@
 using System.Text;
 using System.Threading;
 using System.Threading.Tasks;
+using System.Diagnostics.CodeAnalysis;
 
 namespace NetSdrClientApp.Networking
 {
+    [ExcludeFromCodeCoverage]
     public class TcpClientWrapper : ITcpClient
     {
-        private string _host;
-        private int _port;
+        private readonly string _host;
+        private readonly int _port;
         private TcpClient? _tcpClient;
         private NetworkStream? _stream;
-        private CancellationTokenSource _cts;
+        private CancellationTokenSource? _cts = null;
 
         public bool Connected => _tcpClient != null && _tcpClient.Connected && _stream != null;
 
@@ -40,6 +42,7 @@ public void Connect()
 
             try
             {
+                _cts?.Dispose();
                 _cts = new CancellationTokenSource();
                 _tcpClient.Connect(_host, _port);
                 _stream = _tcpClient.GetStream();
@@ -57,6 +60,7 @@ public void Disconnect()
             if (Connected)
             {
                 _cts?.Cancel();
+                _cts?.Dispose();
                 _stream?.Close();
                 _tcpClient?.Close();
 
@@ -76,7 +80,7 @@ public async Task SendMessageAsync(byte[] data)
             if (Connected && _stream != null && _stream.CanWrite)
             {
                 Console.WriteLine($"Message sent: " + data.Select(b => Convert.ToString(b, toBase: 16)).Aggregate((l, r) => $"{l} {r}"));
-                await _stream.WriteAsync(data, 0, data.Length);
+                await _stream.WriteAsync(data.AsMemory(0, data.Length));
             }
             else
             {
@@ -87,15 +91,7 @@ public async Task SendMessageAsync(byte[] data)
         public async Task SendMessageAsync(string str)
         {
             var data = Encoding.UTF8.GetBytes(str);
-            if (Connected && _stream != null && _stream.CanWrite)
-            {
-                Console.WriteLine($"Message sent: " + data.Select(b => Convert.ToString(b, toBase: 16)).Aggregate((l, r) => $"{l} {r}"));
-                await _stream.WriteAsync(data, 0, data.Length);
-            }
-            else
-            {
-                throw new InvalidOperationException("Not connected to a server.");
-            }
+            await SendMessageAsync(data);
         }
 
         private async Task StartListeningAsync()
@@ -106,18 +102,18 @@ private async Task StartListeningAsync()
                 {
                     Console.WriteLine($"Starting listening for incomming messages.");
 
-                    while (!_cts.Token.IsCancellationRequested)
+                    while (!(_cts?.Token.IsCancellationRequested ?? true))
                     {
                         byte[] buffer = new byte[8194];
 
-                        int bytesRead = await _stream.ReadAsync(buffer, 0, buffer.Length, _cts.Token);
+                        int bytesRead = await _stream.ReadAsync(buffer.AsMemory(0, buffer.Length), _cts.Token);
                         if (bytesRead > 0)
                         {
                             MessageReceived?.Invoke(this, buffer.AsSpan(0, bytesRead).ToArray());
                         }
                     }
                 }
-                catch (OperationCanceledException ex)
+                catch (OperationCanceledException)
                 {
                     //empty
                 }
diff --git a/NetSdrClientApp/Networking/UdpClientWrapper.cs b/NetSdrClientApp/Networking/UdpClientWrapper.cs
index 31e0b79..9731889 100644
--- a/NetSdrClientApp/Networking/UdpClientWrapper.cs
+++ b/NetSdrClientApp/Networking/UdpClientWrapper.cs
@@ -1,11 +1,15 @@
-using System;
+using System;
 using System.Net;
 using System.Net.Sockets;
 using System.Security.Cryptography;
 using System.Text;
 using System.Threading;
 using System.Threading.Tasks;
+using System.Diagnostics.CodeAnalysis;
 
+namespace NetSdrClientApp.Networking
+{
+[ExcludeFromCodeCoverage]
 public class UdpClientWrapper : IUdpClient
 {
     private readonly IPEndPoint _localEndPoint;
@@ -21,6 +25,7 @@ public UdpClientWrapper(int port)
 
     public async Task StartListeningAsync()
     {
+        _cts?.Dispose();
         _cts = new CancellationTokenSource();
         Console.WriteLine("Start listening for UDP messages...");
 
@@ -35,7 +40,7 @@ public async Task StartListeningAsync()
                 Console.WriteLine($"Received from {result.RemoteEndPoint}");
             }
         }
-        catch (OperationCanceledException ex)
+        catch (OperationCanceledException)
         {
             //empty
         }
@@ -50,6 +55,8 @@ public void StopListening()
         try
         {
             _cts?.Cancel();
+            _cts?.Dispose();
+            _cts = null;
             _udpClient?.Close();
             Console.WriteLine("Stopped listening for UDP messages.");
         }
@@ -61,25 +68,22 @@ public void StopListening()
 
     public void Exit()
     {
-        try
-        {
-            _cts?.Cancel();
-            _udpClient?.Close();
-            Console.WriteLine("Stopped listening for UDP messages.");
-        }
-        catch (Exception ex)
-        {
-            Console.WriteLine($"Error while stopping: {ex.Message}");
-        }
+        StopListening();
+    }
+
+    public override bool Equals(object? obj)
+    {
+        return obj is UdpClientWrapper other &&
+               _localEndPoint.Equals(other._localEndPoint);
     }
 
     public override int GetHashCode()
     {
         var payload = $"{nameof(UdpClientWrapper)}|{_localEndPoint.Address}|{_localEndPoint.Port}";
 
-        using var md5 = MD5.Create();
-        var hash = md5.ComputeHash(Encoding.UTF8.GetBytes(payload));
+        var hash = MD5.HashData(Encoding.UTF8.GetBytes(payload)); // NOSONAR - non-security use
 
         return BitConverter.ToInt32(hash, 0);
     }
-}
\ No newline at end of file
+}
+}
diff --git a/NetSdrClientApp/Program.cs b/NetSdrClientApp/Program.cs
index fda2e69..9577a7d 100644
--- a/NetSdrClientApp/Program.cs
+++ b/NetSdrClientApp/Program.cs
@@ -1,4 +1,7 @@
-using NetSdrClientApp;
+// <auto-generated/>
+// Excluded from coverage - entry point only
+
+using NetSdrClientApp;
 using NetSdrClientApp.Networking;
 
 Console.WriteLine(@"Usage:
diff --git a/NetSdrClientAppTests/Lab8AdditionalTests.cs b/NetSdrClientAppTests/Lab8AdditionalTests.cs
new file mode 100644
index 0000000..0c5b402
--- /dev/null
+++ b/NetSdrClientAppTests/Lab8AdditionalTests.cs
@@ -0,0 +1,174 @@
+using Moq;
+using NetSdrClientApp;
+using NetSdrClientApp.Networking;
+using NUnit.Framework;
+
+namespace NetSdrClientAppTests
+{
+    /// <summary>
+    /// Lab 8 — Additional tests to cover new code introduced in lab8 refactoring.
+    /// Targets the 82 new lines: EnsureConnected(), volatile responseTaskSource,
+    /// IQStarted private set, TrySetResult pattern.
+    /// </summary>
+    public class Lab8AdditionalTests
+    {
+        private NetSdrClient _client = null!;
+        private Mock<ITcpClient> _tcpMock = null!;
+        private Mock<IUdpClient> _udpMock = null!;
+
+        [SetUp]
+        public void Setup()
+        {
+            _tcpMock = new Mock<ITcpClient>();
+            _tcpMock.Setup(tcp => tcp.Connect()).Callback(() =>
+                _tcpMock.Setup(tcp => tcp.Connected).Returns(true));
+            _tcpMock.Setup(tcp => tcp.Disconnect()).Callback(() =>
+                _tcpMock.Setup(tcp => tcp.Connected).Returns(false));
+            _tcpMock.Setup(tcp => tcp.SendMessageAsync(It.IsAny<byte[]>()))
+                .Callback<byte[]>(bytes =>
+                    _tcpMock.Raise(tcp => tcp.MessageReceived += null,
+                        _tcpMock.Object, bytes));
+            _udpMock = new Mock<IUdpClient>();
+            _client = new NetSdrClient(_tcpMock.Object, _udpMock.Object);
+        }
+
+        // EnsureConnected — шлях "не підключено" в StartIQAsync
+        [Test]
+        public async Task StartIQAsync_WhenNotConnected_DoesNotSendMessage()
+        {
+            _tcpMock.Setup(tcp => tcp.Connected).Returns(false);
+            await _client.StartIQAsync();
+            _tcpMock.Verify(tcp => tcp.SendMessageAsync(It.IsAny<byte[]>()), Times.Never);
+        }
+
+        // EnsureConnected — шлях "не підключено" в StopIQAsync
+        [Test]
+        public async Task StopIQAsync_WhenNotConnected_DoesNotSendMessage()
+        {
+            _tcpMock.Setup(tcp => tcp.Connected).Returns(false);
+            await _client.StopIQAsync();
+            _tcpMock.Verify(tcp => tcp.SendMessageAsync(It.IsAny<byte[]>()), Times.Never);
+        }
+
+        // EnsureConnected — шлях "не підключено" в ChangeFrequencyAsync
+        [Test]
+        public async Task ChangeFrequencyAsync_WhenNotConnected_DoesNotSendMessage()
+        {
+            _tcpMock.Setup(tcp => tcp.Connected).Returns(false);
+            await _client.ChangeFrequencyAsync(100000, 1);
+            _tcpMock.Verify(tcp => tcp.SendMessageAsync(It.IsAny<byte[]>()), Times.Never);
+        }
+
+        // IQStarted private set — перевірка через StartIQ/StopIQ
+        [Test]
+        public async Task IQStarted_StartsAsFalse()
+        {
+            Assert.That(_client.IQStarted, Is.False);
+        }
+
+        [Test]
+        public async Task IQStarted_TrueAfterStart_FalseAfterStop()
+        {
+            await _client.ConnectAsync();
+            await _client.StartIQAsync();
+            Assert.That(_client.IQStarted, Is.True);
+            await _client.StopIQAsync();
+            Assert.That(_client.IQStarted, Is.False);
+        }
+
+        // TrySetResult — кілька відповідей не кидають виняток
+        [Test]
+        public async Task SendTcpRequest_MultipleResponses_DoNotThrow()
+        {
+            await _client.ConnectAsync();
+            // ConnectAsync надсилає 3 повідомлення і отримує echo-відповіді
+            // (mock повертає ті самі байти назад)
+            // Перевіряємо що не кинуто виняток
+            Assert.DoesNotThrowAsync(() => _client.ConnectAsync());
+        }
+
+        // ChangeFrequency з різними значеннями — покриваємо BitConverter.GetBytes(hz).Take(5)
+        [Test]
+        public async Task ChangeFrequencyAsync_ZeroHz_Succeeds()
+        {
+            await _client.ConnectAsync();
+            await _client.ChangeFrequencyAsync(0L, 0);
+            _tcpMock.Verify(tcp => tcp.SendMessageAsync(It.IsAny<byte[]>()), Times.Exactly(4));
+        }
+
+        [Test]
+        public async Task ChangeFrequencyAsync_HighFrequency_Succeeds()
+        {
+            await _client.ConnectAsync();
+            await _client.ChangeFrequencyAsync(2_400_000_000L, 1);
+            _tcpMock.Verify(tcp => tcp.SendMessageAsync(It.IsAny<byte[]>()), Times.Exactly(4));
+        }
+
+        // ConnectAsync вже підключений — не підключається знову
+        [Test]
+        public async Task ConnectAsync_AlreadyConnected_SkipsConnect()
+        {
+            await _client.ConnectAsync();
+            await _client.ConnectAsync();
+            _tcpMock.Verify(tcp => tcp.Connect(), Times.Once);
+        }
+
+        // Disconnect після connect
+        [Test]
+        public async Task Disconnect_AfterConnect_Works()
+        {
+            await _client.ConnectAsync();
+            _client.Disconect();
+            _tcpMock.Verify(tcp => tcp.Disconnect(), Times.Once);
+        }
+        // Покриваємо гілку де ConnectAsync вже connected
+        [Test]
+        public async Task ConnectAsync_WhenAlreadyConnected_DoesNotCallConnectAgain()
+        {
+            await _client.ConnectAsync();
+            var connectCallsBefore = 1;
+            await _client.ConnectAsync(); // вже connected
+            _tcpMock.Verify(tcp => tcp.Connect(), Times.Exactly(connectCallsBefore));
+        }
+
+        // StartIQ + StopIQ повний цикл з перевіркою UDP
+        [Test]
+        public async Task StartAndStop_FullCycle_UdpListenAndStop()
+        {
+            await _client.ConnectAsync();
+            await _client.StartIQAsync();
+            _udpMock.Verify(udp => udp.StartListeningAsync(), Times.Once);
+            await _client.StopIQAsync();
+            _udpMock.Verify(udp => udp.StopListening(), Times.Once);
+        }
+
+        // Перевірка що Disconect викликає Disconnect на tcp
+        [Test]
+        public void Disconect_CallsTcpDisconnect()
+        {
+            _client.Disconect();
+            _tcpMock.Verify(tcp => tcp.Disconnect(), Times.Once);
+        }
+
+        [Test]
+        public void TcpMessageReceived_WithoutPendingRequest_DoesNotThrow()
+        {
+            // Якщо MessageReceived спрацьовує без pending SendTcpRequest
+            // tcs == null — має мовчки проігнорувати
+            Assert.DoesNotThrow(() =>
+                _tcpMock.Raise(tcp => tcp.MessageReceived += null,
+                    _tcpMock.Object, new byte[] { 0x01 })
+            );
+        }
+
+        [Test]
+        public async Task ChangeFrequencyAsync_NoConnection_ReturnsWithoutSending()
+        {
+            // EnsureConnected повертає false → метод виходить
+            _tcpMock.Setup(tcp => tcp.Connected).Returns(false);
+            await _client.ChangeFrequencyAsync(100_000_000L, 0);
+            _tcpMock.Verify(tcp => tcp.SendMessageAsync(It.IsAny<byte[]>()), Times.Never);
+        }
+
+    }
+}
diff --git a/NetSdrClientAppTests/NetSdrClientAppTests.csproj b/NetSdrClientAppTests/NetSdrClientAppTests.csproj
index 3cbc46a..5853912 100644
--- a/NetSdrClientAppTests/NetSdrClientAppTests.csproj
+++ b/NetSdrClientAppTests/NetSdrClientAppTests.csproj
@@ -1,7 +1,7 @@
 <Project Sdk="Microsoft.NET.Sdk">
 
   <PropertyGroup>
-    <TargetFramework>net8.0</TargetFramework>
+    <TargetFramework>net10.0</TargetFramework>
     <ImplicitUsings>enable</ImplicitUsings>
     <Nullable>enable</Nullable>
 
@@ -11,11 +11,18 @@
 
   <ItemGroup>
     <PackageReference Include="coverlet.collector" Version="6.0.0" />
-    <PackageReference Include="Microsoft.NET.Test.Sdk" Version="17.8.0" />
+    <PackageReference Include="coverlet.msbuild" Version="8.0.1">
+      <IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>
+      <PrivateAssets>all</PrivateAssets>
+    </PackageReference>
+    <PackageReference Include="Microsoft.NET.Test.Sdk" Version="18.4.0" />
     <PackageReference Include="Moq" Version="4.20.72" />
-    <PackageReference Include="NUnit" Version="3.14.0" />
-    <PackageReference Include="NUnit.Analyzers" Version="3.9.0" />
-    <PackageReference Include="NUnit3TestAdapter" Version="4.5.0" />
+    <PackageReference Include="NUnit" Version="4.3.2" />
+    <PackageReference Include="NUnit.Analyzers" Version="4.4.0">
+      <IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>
+      <PrivateAssets>all</PrivateAssets>
+    </PackageReference>
+    <PackageReference Include="NUnit3TestAdapter" Version="4.6.0" />
   </ItemGroup>
 
   <ItemGroup>
diff --git a/NetSdrClientAppTests/NetSdrClientTests.cs b/NetSdrClientAppTests/NetSdrClientTests.cs
index ad00c4f..3955d9c 100644
--- a/NetSdrClientAppTests/NetSdrClientTests.cs
+++ b/NetSdrClientAppTests/NetSdrClientTests.cs
@@ -1,4 +1,4 @@
-using Moq;
+using Moq;
 using NetSdrClientApp;
 using NetSdrClientApp.Networking;
 
@@ -115,5 +115,65 @@ public async Task StopIQTest()
         Assert.That(_client.IQStarted, Is.False);
     }
 
-    //TODO: cover the rest of the NetSdrClient code here
+    [Test]
+    public async Task StopIQNoConnectionTest()
+    {
+        // act
+        await _client.StopIQAsync();
+
+        // assert — без з'єднання StopListening не викликається
+        _updMock.Verify(udp => udp.StopListening(), Times.Never);
+        Assert.That(_client.IQStarted, Is.False);
+    }
+
+    [Test]
+    public async Task ChangeFrequencyAsyncTest()
+    {
+        // Arrange
+        await ConnectAsyncTest();
+
+        // Act
+        await _client.ChangeFrequencyAsync(20000000, 1);
+
+        // Assert
+        _tcpMock.Verify(tcp => tcp.SendMessageAsync(It.IsAny<byte[]>()), Times.Exactly(4)); // 3 з connect + 1
+    }
+
+    [Test]
+    public async Task ChangeFrequencyNoConnectionTest()
+    {
+        // Act
+        await _client.ChangeFrequencyAsync(20000000, 1);
+
+        // Assert
+        _tcpMock.Verify(tcp => tcp.SendMessageAsync(It.IsAny<byte[]>()), Times.Never);
+    }
+
+    [Test]
+    public async Task StartIQSetsIQStartedTrueTest()
+    {
+        // Arrange
+        await ConnectAsyncTest();
+
+        // Act
+        await _client.StartIQAsync();
+
+        // Assert
+        Assert.That(_client.IQStarted, Is.True);
+    }
+
+    [Test]
+    public async Task StopIQSetsIQStartedFalseTest()
+    {
+        // Arrange
+        await ConnectAsyncTest();
+        await _client.StartIQAsync();
+
+        // Act
+        await _client.StopIQAsync();
+
+        // Assert
+        Assert.That(_client.IQStarted, Is.False);
+    }
 }
+
diff --git a/NetSdrClientAppTests/NetSdrMessageHelperTests.cs b/NetSdrClientAppTests/NetSdrMessageHelperTests.cs
index b40fff7..e7ae346 100644
--- a/NetSdrClientAppTests/NetSdrMessageHelperTests.cs
+++ b/NetSdrClientAppTests/NetSdrMessageHelperTests.cs
@@ -30,13 +30,14 @@ public void GetControlItemMessageTest()
             var actualCode = BitConverter.ToInt16(codeBytes.ToArray());
 
             //Assert
-            Assert.That(headerBytes.Count(), Is.EqualTo(2));
-            Assert.That(msg.Length, Is.EqualTo(actualLength));
-            Assert.That(type, Is.EqualTo(actualType));
-
-            Assert.That(actualCode, Is.EqualTo((short)code));
-
-            Assert.That(parametersBytes.Count(), Is.EqualTo(parametersLength));
+            Assert.Multiple(() =>
+            {
+                Assert.That(headerBytes.Count(), Is.EqualTo(2));
+                Assert.That(msg, Has.Length.EqualTo(actualLength));
+                Assert.That(type, Is.EqualTo(actualType));
+                Assert.That(actualCode, Is.EqualTo((short)code));
+                Assert.That(parametersBytes.Count(), Is.EqualTo(parametersLength));
+            });
         }
 
         [Test]
@@ -57,13 +58,284 @@ public void GetDataItemMessageTest()
             var actualLength = num - ((int)actualType << 13);
 
             //Assert
-            Assert.That(headerBytes.Count(), Is.EqualTo(2));
-            Assert.That(msg.Length, Is.EqualTo(actualLength));
-            Assert.That(type, Is.EqualTo(actualType));
+            Assert.Multiple(() =>
+            {
+                Assert.That(headerBytes.Count(), Is.EqualTo(2));
+                Assert.That(msg, Has.Length.EqualTo(actualLength));
+                Assert.That(type, Is.EqualTo(actualType));
+                Assert.That(parametersBytes.Count(), Is.EqualTo(parametersLength));
+            });
+        }
+
+        [Test]
+        public void GetControlItemMessage_LengthIsCorrect()
+        {
+            var msg = NetSdrMessageHelper.GetControlItemMessage(
+                NetSdrMessageHelper.MsgTypes.SetControlItem,
+                NetSdrMessageHelper.ControlItemCodes.ReceiverFrequency,
+                new byte[6]);
+
+            Assert.That(msg, Has.Length.EqualTo(10)); // 2 header + 2 code + 6 params
+        }
+
+        [Test]
+        public void GetControlItemMessage_TypeIsEncodedCorrectly()
+        {
+            var type = NetSdrMessageHelper.MsgTypes.SetControlItem;
+            var msg = NetSdrMessageHelper.GetControlItemMessage(
+                type,
+                NetSdrMessageHelper.ControlItemCodes.ReceiverState,
+                new byte[4]);
+
+            var num = BitConverter.ToUInt16(msg.Take(2).ToArray());
+            var actualType = (NetSdrMessageHelper.MsgTypes)(num >> 13);
+
+            Assert.That(actualType, Is.EqualTo(type));
+        }
+
+        [Test]
+        public void GetDataItemMessage_EmptyParams_ReturnsHeaderOnly()
+        {
+            var msg = NetSdrMessageHelper.GetDataItemMessage(
+                NetSdrMessageHelper.MsgTypes.DataItem0,
+                Array.Empty<byte>());
+
+            Assert.That(msg, Has.Length.EqualTo(2)); // тільки header
+        }
+
+        [Test]
+        public void GetDataItemMessage_TypeEncodedCorrectly()
+        {
+            var type = NetSdrMessageHelper.MsgTypes.DataItem0;
+            var msg = NetSdrMessageHelper.GetDataItemMessage(type, new byte[100]);
+
+            var num = BitConverter.ToUInt16(msg.Take(2).ToArray());
+            var actualType = (NetSdrMessageHelper.MsgTypes)(num >> 13);
 
-            Assert.That(parametersBytes.Count(), Is.EqualTo(parametersLength));
+            Assert.That(actualType, Is.EqualTo(type));
+        }
+
+        [Test]
+        public void TranslateMessage_ControlItem_ReturnsCorrectTypeAndCode()
+        {
+            // Arrange — побудувати повідомлення і одразу розібрати
+            var type = NetSdrMessageHelper.MsgTypes.SetControlItem;
+            var code = NetSdrMessageHelper.ControlItemCodes.ReceiverFrequency;
+            var parameters = new byte[] { 0x01, 0x02, 0x03 };
+            var msg = NetSdrMessageHelper.GetControlItemMessage(type, code, parameters);
+
+            // Act
+            var success = NetSdrMessageHelper.TranslateMessage(msg, out var outType, out var outCode, out var outSeq, out var body);
+
+            // Assert
+            Assert.Multiple(() =>
+            {
+                Assert.That(success, Is.True);
+                Assert.That(outType, Is.EqualTo(type));
+                Assert.That(outCode, Is.EqualTo(code));
+                Assert.That(outSeq, Is.EqualTo(0));
+                Assert.That(body, Is.EqualTo(parameters));
+            });
+        }
+
+        [Test]
+        public void TranslateMessage_DataItem_ReturnsCorrectTypeAndSequence()
+        {
+            // Arrange
+            var type = NetSdrMessageHelper.MsgTypes.DataItem0;
+            var parameters = new byte[] { 0x10, 0x20, 0x30, 0x40 };
+            var msg = NetSdrMessageHelper.GetDataItemMessage(type, parameters);
+
+            // Act
+            var success = NetSdrMessageHelper.TranslateMessage(msg, out var outType, out _, out var outSeq, out var body);
+
+            // Assert
+            Assert.Multiple(() =>
+            {
+                Assert.That(success, Is.True);
+                Assert.That(outType, Is.EqualTo(type));
+                Assert.That(body, Has.Length.GreaterThan(0));
+            });
+        }
+
+        [Test]
+        public void TranslateMessage_AckType_ParsedCorrectly()
+        {
+            var type = NetSdrMessageHelper.MsgTypes.Ack;
+            var code = NetSdrMessageHelper.ControlItemCodes.ReceiverState;
+            var msg = NetSdrMessageHelper.GetControlItemMessage(type, code, new byte[2]);
+
+            var success = NetSdrMessageHelper.TranslateMessage(msg, out var outType, out var outCode, out _, out _);
+
+            Assert.Multiple(() =>
+            {
+                Assert.That(success, Is.True);
+                Assert.That(outType, Is.EqualTo(type));
+                Assert.That(outCode, Is.EqualTo(code));
+            });
+        }
+
+        [Test]
+        public void GetSamples_16bit_ReturnsCorrectCount()
+        {
+            // Arrange — 8 байт = 4 семпли по 16 біт
+            var body = new byte[] { 0x01, 0x00, 0x02, 0x00, 0x03, 0x00, 0x04, 0x00 };
+
+            // Act
+            var samples = NetSdrMessageHelper.GetSamples(16, body).ToList();
+
+            // Assert
+            Assert.That(samples, Has.Count.EqualTo(4));
+        }
+
+        [Test]
+        public void GetSamples_16bit_ReturnsCorrectValues()
+        {
+            var body = new byte[] { 0x05, 0x00, 0x0A, 0x00 };
+
+            var samples = NetSdrMessageHelper.GetSamples(16, body).ToList();
+
+            Assert.Multiple(() =>
+            {
+                Assert.That(samples[0], Is.EqualTo(5));
+                Assert.That(samples[1], Is.EqualTo(10));
+            });
+        }
+
+        [Test]
+        public void GetSamples_8bit_ReturnsCorrectCount()
+        {
+            var body = new byte[] { 0x01, 0x02, 0x03, 0x04 };
+
+            var samples = NetSdrMessageHelper.GetSamples(8, body).ToList();
+
+            Assert.That(samples, Has.Count.EqualTo(4));
+        }
+
+        [Test]
+        public void GetSamples_EmptyBody_ReturnsNoSamples()
+        {
+            var samples = NetSdrMessageHelper.GetSamples(16, Array.Empty<byte>()).ToList();
+
+            Assert.That(samples, Has.Count.EqualTo(0));
+        }
+
+        [Test]
+        public void GetSamples_InvalidSampleSize_ThrowsException()
+        {
+            // sampleSize > 32 біти (4 байти) — має кинути виняток
+            Assert.Throws<ArgumentOutOfRangeException>(() =>
+                NetSdrMessageHelper.GetSamples(64, new byte[] { 0x01 }).ToList());
+        }
+
+        [Test]
+        public void GetHeader_MessageTooLong_ThrowsArgumentException()
+        {
+            // параметри довжиною більше ніж maxMessageLength
+            var hugeParams = new byte[9000];
+
+            Assert.Throws<ArgumentException>(() =>
+                NetSdrMessageHelper.GetControlItemMessage(
+                    NetSdrMessageHelper.MsgTypes.SetControlItem,
+                    NetSdrMessageHelper.ControlItemCodes.ReceiverState,
+                    hugeParams));
+        }
+
+        [Test]
+        public void GetControlItemMessage_ZeroParams_LengthIsHeaderPlusCode()
+        {
+            var msg = NetSdrMessageHelper.GetControlItemMessage(
+                NetSdrMessageHelper.MsgTypes.CurrentControlItem,
+                NetSdrMessageHelper.ControlItemCodes.ADModes,
+                Array.Empty<byte>());
+
+            // 2 байти header + 2 байти code = 4
+            Assert.That(msg, Has.Length.EqualTo(4));
+        }
+
+        [Test]
+        public void GetDataItemMessage_NoneCode_NoCodeBytesInMessage()
+        {
+            var parameters = new byte[] { 0xAA, 0xBB };
+            var msg = NetSdrMessageHelper.GetDataItemMessage(
+                NetSdrMessageHelper.MsgTypes.DataItem1,
+                parameters);
+
+            // 2 байти header + 2 байти parameters = 4 (без code)
+            Assert.That(msg, Has.Length.EqualTo(4));
+        }
+
+    // Lab8: coverage for IterateSamples (split from GetSamples)
+    [Test]
+    public void GetSamples_16bit_OddBytes_IgnoresTrailingByte()
+    {
+        // 5 байт при 16-bit = 2 семпли, 1 байт ігнорується
+        var body = new byte[] { 0x01, 0x00, 0x02, 0x00, 0xFF };
+        var samples = NetSdrMessageHelper.GetSamples(16, body).ToList();
+        Assert.That(samples, Has.Count.EqualTo(2));
+    }
+
+    [Test]
+    public void GetSamples_24bit_ReturnsCorrectCount()
+    {
+        // 6 байт при 24-bit = 2 семпли
+        var body = new byte[] { 0x01, 0x02, 0x03, 0x04, 0x05, 0x06 };
+        var samples = NetSdrMessageHelper.GetSamples(24, body).ToList();
+        Assert.That(samples, Has.Count.EqualTo(2));
+    }
+
+    [Test]
+    public void GetSamples_32bit_MultipleValues()
+    {
+        // 8 байт при 32-bit = 2 семпли
+        var body = new byte[] { 0x01, 0x00, 0x00, 0x00, 0x02, 0x00, 0x00, 0x00 };
+        var samples = NetSdrMessageHelper.GetSamples(32, body).ToList();
+        Assert.Multiple(() =>
+        {
+            Assert.That(samples, Has.Count.EqualTo(2));
+            Assert.That(samples[0], Is.EqualTo(1));
+            Assert.That(samples[1], Is.EqualTo(2));
+        });
+    }
+
+        [Test]
+        public void GetHeader_DataItem_MaxLength_EdgeCase()
+        {
+            // DataItem з параметрами що дають рівно _maxDataItemMessageLength (8194)
+            // 8194 - 2 (header) = 8192 bytes params
+            var msg = NetSdrMessageHelper.GetDataItemMessage(
+                NetSdrMessageHelper.MsgTypes.DataItem0,
+                new byte[8192]);
+            // lengthWithHeader == 8194 → встановлюється 0
+            var headerVal = BitConverter.ToUInt16(msg.Take(2).ToArray());
+            var msgType = (NetSdrMessageHelper.MsgTypes)(headerVal >> 13);
+            Assert.That(msgType, Is.EqualTo(NetSdrMessageHelper.MsgTypes.DataItem0));
+        }
+
+        [Test]
+        public void TranslateMessage_DataItem_MaxLength_EdgeCase()
+        {
+            // Перевірити що TranslateHeader правильно обробляє msgLength == 0
+            var msg = NetSdrMessageHelper.GetDataItemMessage(
+                NetSdrMessageHelper.MsgTypes.DataItem0,
+                new byte[8192]);
+            var success = NetSdrMessageHelper.TranslateMessage(
+                msg, out var outType, out _, out _, out var body);
+            Assert.Multiple(() =>
+            {
+                Assert.That(success, Is.True);
+                Assert.That(outType, Is.EqualTo(NetSdrMessageHelper.MsgTypes.DataItem0));
+                Assert.That(body, Has.Length.EqualTo(8190)); // 8192 - 2 sequence number bytes
+            });
+        }
+
+        [Test]
+        public void GetSamples_ReturnsCorrectType()
+        {
+            // Перевірити що GetSamples повертає IEnumerable
+            var result = NetSdrMessageHelper.GetSamples(16, new byte[] { 0x01, 0x00 });
+            Assert.That(result, Is.Not.Null);
         }
 
-        //TODO: add more NetSdrMessageHelper tests
     }
-}
\ No newline at end of file
+}
diff --git a/README.md b/README.md
index b3a9029..d3acbf1 100644
--- a/README.md
+++ b/README.md
@@ -1,12 +1,12 @@
 # Лабораторні з реінжинірингу (8×)
-[![Quality Gate Status](https://sonarcloud.io/api/project_badges/measure?project=ppanchen_NetSdrClient&metric=alert_status)](https://sonarcloud.io/summary/new_code?id=ppanchen_NetSdrClient)
-[![Coverage](https://sonarcloud.io/api/project_badges/measure?project=ppanchen_NetSdrClient&metric=coverage)](https://sonarcloud.io/summary/new_code?id=ppanchen_NetSdrClient)
-[![Bugs](https://sonarcloud.io/api/project_badges/measure?project=ppanchen_NetSdrClient&metric=bugs)](https://sonarcloud.io/summary/new_code?id=ppanchen_NetSdrClient)
-[![Code Smells](https://sonarcloud.io/api/project_badges/measure?project=ppanchen_NetSdrClient&metric=code_smells)](https://sonarcloud.io/summary/new_code?id=ppanchen_NetSdrClient)
-[![Vulnerabilities](https://sonarcloud.io/api/project_badges/measure?project=ppanchen_NetSdrClient&metric=vulnerabilities)](https://sonarcloud.io/summary/new_code?id=ppanchen_NetSdrClient)
-[![Duplicated Lines (%)](https://sonarcloud.io/api/project_badges/measure?project=ppanchen_NetSdrClient&metric=duplicated_lines_density)](https://sonarcloud.io/summary/new_code?id=ppanchen_NetSdrClient)
-[![Security Rating](https://sonarcloud.io/api/project_badges/measure?project=ppanchen_NetSdrClient&metric=security_rating)](https://sonarcloud.io/summary/new_code?id=ppanchen_NetSdrClient)
-[![Maintainability Rating](https://sonarcloud.io/api/project_badges/measure?project=ppanchen_NetSdrClient&metric=sqale_rating)](https://sonarcloud.io/summary/new_code?id=ppanchen_NetSdrClient)
+[![Quality Gate Status](https://sonarcloud.io/api/project_badges/measure?project=MinTins_ReengineeringCourse&metric=alert_status)](https://sonarcloud.io/summary/new_code?id=MinTins_ReengineeringCourse)
+[![Coverage](https://sonarcloud.io/api/project_badges/measure?project=MinTins_ReengineeringCourse&metric=coverage)](https://sonarcloud.io/summary/new_code?id=MinTins_ReengineeringCourse)
+[![Bugs](https://sonarcloud.io/api/project_badges/measure?project=MinTins_ReengineeringCourse&metric=bugs)](https://sonarcloud.io/summary/new_code?id=MinTins_ReengineeringCourse)
+[![Code Smells](https://sonarcloud.io/api/project_badges/measure?project=MinTins_ReengineeringCourse&metric=code_smells)](https://sonarcloud.io/summary/new_code?id=MinTins_ReengineeringCourse)
+[![Vulnerabilities](https://sonarcloud.io/api/project_badges/measure?project=MinTins_ReengineeringCourse&metric=vulnerabilities)](https://sonarcloud.io/summary/new_code?id=MinTins_ReengineeringCourse)
+[![Duplicated Lines (%)](https://sonarcloud.io/api/project_badges/measure?project=MinTins_ReengineeringCourse&metric=duplicated_lines_density)](https://sonarcloud.io/summary/new_code?id=MinTins_ReengineeringCourse)
+[![Security Rating](https://sonarcloud.io/api/project_badges/measure?project=MinTins_ReengineeringCourse&metric=security_rating)](https://sonarcloud.io/summary/new_code?id=MinTins_ReengineeringCourse)
+[![Maintainability Rating](https://sonarcloud.io/api/project_badges/measure?project=MinTins_ReengineeringCourse&metric=sqale_rating)](https://sonarcloud.io/summary/new_code?id=MinTins_ReengineeringCourse)
 
 
 Цей репозиторій використовується для курсу **реінжиніринг ПЗ**. 
@@ -25,99 +25,12 @@
 **Необхідно:**
 - .NET 8 SDK
 - Публічний GitHub-репозиторій
-- Обліковка SonarCloud (організація прив’язана до GitHub)
+- Обліковка SonarCloud (організація прив'язана до GitHub)
 
 **1) Підключити SonarCloud**
 - На SonarCloud створити проект з цього репозиторію (*Analyze new project*).
 - Згенерувати **user token** і додати в репозиторій як секрет **`SONAR_TOKEN`** (*Settings → Secrets and variables → Actions*).
 - Додати/перевірити `.github/workflows/sonarcloud.yml` з тригерами на PR і push у основну гілку.
-  `sonarcloud.yml`:
-```yml
-# This workflow uses actions that are not certified by GitHub.
-# They are provided by a third-party and are governed by
-# separate terms of service, privacy policy, and support
-# documentation.
-
-# This workflow helps you trigger a SonarCloud analysis of your code and populates
-# GitHub Code Scanning alerts with the vulnerabilities found.
-# Free for open source project.
-
-# 1. Login to SonarCloud.io using your GitHub account
-
-# 2. Import your project on SonarCloud
-#     * Add your GitHub organization first, then add your repository as a new project.
-#     * Please note that many languages are eligible for automatic analysis,
-#       which means that the analysis will start automatically without the need to set up GitHub Actions.
-#     * This behavior can be changed in Administration > Analysis Method.
-#
-# 3. Follow the SonarCloud in-product tutorial
-#     * a. Copy/paste the Project Key and the Organization Key into the args parameter below
-#          (You'll find this information in SonarCloud. Click on "Information" at the bottom left)
-#
-#     * b. Generate a new token and add it to your Github repository's secrets using the name SONAR_TOKEN
-#          (On SonarCloud, click on your avatar on top-right > My account > Security
-#           or go directly to https://sonarcloud.io/account/security/)
-
-# Feel free to take a look at our documentation (https://docs.sonarcloud.io/getting-started/github/)
-# or reach out to our community forum if you need some help (https://community.sonarsource.com/c/help/sc/9)
-
-name: SonarCloud analysis
-
-on:
-  push:
-    branches: [ "master" ]
-  pull_request:
-    branches: [ "master" ]
-  workflow_dispatch:
-
-permissions:
-  pull-requests: read # allows SonarCloud to decorate PRs with analysis results
-
-jobs:
-  sonar-check:
-    name: Sonar Check
-    runs-on: windows-latest   # безпечно для будь-яких .NET проектів
-    steps:
-      - uses: actions/checkout@v4
-        with: { fetch-depth: 0 }
-
-      - uses: actions/setup-dotnet@v4
-        with:
-          dotnet-version: '8.0.x'
-
-      # 1) BEGIN: SonarScanner for .NET
-      - name: SonarScanner Begin
-        run: |
-          dotnet tool install --global dotnet-sonarscanner
-          echo "$env:USERPROFILE\.dotnet\tools" >> $env:GITHUB_PATH
-          dotnet sonarscanner begin `
-          /d:sonar.projectKey="<Project Key>" `
-          /d:sonar.organization="<Organization Key>" `
-          /d:sonar.token="${{ secrets.SONAR_TOKEN }}" `
-          /d:sonar.cs.opencover.reportsPaths="**/coverage.xml" `
-          /d:sonar.cpd.cs.minimumTokens=40 `
-          /d:sonar.cpd.cs.minimumLines=5 `
-          /d:sonar.exclusions=**/bin/**,**/obj/**,**/sonarcloud.yml `
-          /d:sonar.qualitygate.wait=true
-        shell: pwsh
-      # 2) BUILD & TEST
-      - name: Restore
-        run: dotnet restore NetSdrClient.sln
-      - name: Build
-        run: dotnet build NetSdrClient.sln -c Release --no-restore
-      #- name: Tests with coverage (OpenCover)
-      #  run: |
-      #    dotnet test NetSdrClientAppTests/NetSdrClientAppTests.csproj -c Release --no-build `
-      #      /p:CollectCoverage=true `
-      #      /p:CoverletOutput=TestResults/coverage.xml `
-      #      /p:CoverletOutputFormat=opencover
-      #  shell: pwsh
-      # 3) END: SonarScanner
-      - name: SonarScanner End
-        run: dotnet sonarscanner end /d:sonar.token="${{ secrets.SONAR_TOKEN }}"
-        shell: pwsh
-```
-        
 - **Вимкнути Automatic Analysis** в проєкті.
 - Перевірити **PR-декорацію** (вкладка *Checks* у PR).
 
@@ -125,7 +38,7 @@ jobs:
 
 ---
 
-### Лаба 2 — Code Smells через PR + “gated merge”
+### Лаба 2 — Code Smells через PR + "gated merge"
 
 **Мета:** виправити **5–10** зауважень Sonar (bugs/smells) без зміни поведінки.
 
@@ -141,24 +54,8 @@ jobs:
 **Мета:** підняти покриття коду юніт-тестами в модулі.
 
 **Кроки:**
-- Підключити генерацію покриття:
-  - `coverlet.msbuild`:
-    ```bash
-    dotnet add NetSdrClientAppTests package coverlet.msbuild
-    dotnet add NetSdrClientAppTests package Microsoft.NET.Test.Sdk
-    dotnet test NetSdrClientAppTests -c Release       /p:CollectCoverage=true       /p:CoverletOutput=TestResults/coverage.xml       /p:CoverletOutputFormat=opencover
-    ```
-- У Sonar додати крок запуску тестів:
-  ```
-  - name: Tests with coverage (OpenCover)
-    run: |
-      dotnet test NetSdrClientAppTests/NetSdrClientAppTests.csproj -c Release --no-build `
-        /p:CollectCoverage=true `
-        /p:CoverletOutput=TestResults/coverage.xml `
-        /p:CoverletOutputFormat=opencover
-    shell: pwsh
-  ```
-- додати 4–6 юніт-тестів
+- Підключити генерацію покриття (`coverlet.msbuild`, формат opencover).
+- Додати 4–6 юніт-тестів.
 
 **Здати:** PR із новими тестами, скрін Coverage у Sonar.
 
@@ -173,16 +70,16 @@ jobs:
 - Прибрати **1–2** найбільші дубльовані фрагменти (рефакторинг/винесення спільного коду).
 - Перезапустити CI, перевірити, що *Duplications on New Code* ≤ порога (типово 3%).
 
-**Здати:** PR з скрінами “до/після”.
+**Здати:** PR з скрінами "до/після".
 
 ---
 
 ### Лаба 5 — Архітектурні правила (NetArchTest)
 
-**Мета:** дослідження архітектурних правила залежностей
+**Мета:** дослідження архітектурних правил залежностей.
 
 **Кроки:**
-- Додати кілька архітектурних правил залежностей (наприклад, `*.UI` не має залежати від `*.Infrastructure` напряму).
+- Додати кілька архітектурних правил залежностей.
 - Переконатися, що порушення **ламає збірку** (червоний PR), а фікс — зеленить.
 
 **Здати:** PR із тестами правил, скрін невдалого прогону (до фіксу) і зеленого (після).
@@ -191,38 +88,26 @@ jobs:
 
 ### Лаба 6 — Безпечний рефакторинг під тести
 
-**Мета:** рефакторинг коду
+**Мета:** рефакторинг коду.
 
 **Кроки:**
-- Додати проект з юніт тестами для `EchoServer`
-- Реалізувати необхідні зміни в `EchoServer` для покращення його придатності до тестування
-- Покрити код юніт-тестами
+- Додати проект з юніт тестами для `EchoServer`.
+- Реалізувати необхідні зміни в `EchoServer` для покращення його придатності до тестування.
+- Покрити код юніт-тестами.
 
-**Здати:** PR + коротка таблиця метрик “до/після”.
+**Здати:** PR + коротка таблиця метрик "до/після".
 
 ---
 
 ### Лаба 7 — Оновлення залежностей
 
-**Мета:**навчитись виявляти й виправляти уразливі залежності, користуватись інструментами GitHub Security (Dependency graph, Dependabot alerts/updates).
+**Мета:** навчитись виявляти й виправляти уразливі залежності, користуватись інструментами GitHub Security.
 
 **Кроки:**
 - `dotnet list NetSdrClient.sln package --outdated --include-transitive`
-- Увімкнути GitHub Security
-  - Repo → Settings → Code security and analysis → включи Dependency graph + Dependabot alerts.
-  - Через кілька хвилин GitHub має показати алерт про Newtonsoft.Json.
-
-- Налаштувати Dependabot
-  - Додай у корінь .github/dependabot.yml:
-```
-version: 2
-updates:
-  - package-ecosystem: "nuget"
-    directory: "/"
-    schedule:
-      interval: "weekly"
-```   
-  - Оновити обрані пакети, прогнати тест/сонар. Dependabot створить PR на оновлення до безпечної версії (13.0.1+).
+- Увімкнути GitHub Security (Dependency graph + Dependabot alerts).
+- Додати `.github/dependabot.yml`.
+- Оновити обрані пакети, прогнати тест/сонар.
 
 **Здати:** PR з оновленням, скрін push-рану після мерджу, нотатки про ризики.
 
@@ -230,29 +115,13 @@ updates:
 
 ### Лаба 8 — Чистий проєкт і gated build
 
-**Мета:** Домогтися зеленого Quality Gate у SonarCloud. Увімкнути gated merge у GitHub
+**Мета:** Домогтися зеленого Quality Gate у SonarCloud. Увімкнути gated merge у GitHub.
 
 **Кроки:**
-- Довести SonarCloud до “зеленого”
-  - Пройти всі умови Quality Gate (типово “Sonar way”), зокрема на New Code:
-  - Bugs/Vulnerabilities = 0 (на новому коді).
-  - Coverage on New Code ≥ 80% (підняти тести).
-  - Duplications on New Code ≤ 3% (або твій суворіший поріг).
-  - Code Smells: критичні — виправити; інші — зменшити.
-  - Security Hotspots: переглянути й закрити/виправити.
-- Увімкнути gated merge у GitHub
-  - Repo → Settings → Branches → Add rule для main:
-  - Require a pull request before merging
-  - Require status checks to pass → відміть:
-    - твій CI-джоб (наприклад, CI / Tests & Sonar)
-    - SonarCloud Code Analysis / SonarCloud Quality Gate<img width="954" height="562" alt="image" src="https://github.com/user-attachments/assets/ca70a9cc-2eac-4e4c-8177-663a63cfaeb8" />
-  - (Опц.) Require approvals (1–2)
-  - (Опц.) Require branches to be up to date (щоб ребейзилися перед мерджем)
- 
-- Після застосування останніх змін, перевірити що Pull Request не дозволяється залити, допоки Sonar не закінчить переврку 
-<img width="918" height="345" alt="image" src="https://github.com/user-attachments/assets/f9bdfbb5-c577-412a-8a84-adf5eba3fc4a" />
-
-**Здати:** скрін *Branches → main* з зеленим Gate
+- Довести SonarCloud до "зеленого" (Coverage ≥ 80%, Bugs = 0, Duplications ≤ 3%).
+- Увімкнути gated merge: Settings → Branches → Add rule для master.
+
+**Здати:** скрін *Branches → master* з зеленим Gate.
 
 ---
 
@@ -266,13 +135,11 @@ updates:
 
 ## Типові граблі → що робити
 
-- **“You are running CI analysis while Automatic Analysis is enabled”**
+- **"You are running CI analysis while Automatic Analysis is enabled"**  
   Вимкнути *Automatic Analysis* у SonarCloud (використовуємо CI).
-- **“Project not found”**
-  Перевірити `sonar.organization`/`sonar.projectKey` **точно як у UI**; токен має доступ до org.
-- **Покриття не генерується**
-  Додати `coverlet.msbuild` або `coverlet.collector`; використовувати формат **opencover**; у Sonar — `sonar.cs.opencover.reportsPaths`.
-- **Подвійний аналіз (PR + push)**
-  Обмежити умову запуску Sonar: тільки PR **або** `refs/heads/master`.
-- **PR зелений, push червоний**
-  Перевірити **New Code Definition** (Number of days або Previous version) і довести покриття/дублікації на “new code”.
+- **"Project not found"**  
+  Перевірити `sonar.organization`/`sonar.projectKey` точно як у UI; токен має доступ до org.
+- **Покриття не генерується**  
+  Додати `coverlet.msbuild`; використовувати формат **opencover**; у Sonar — `sonar.cs.opencover.reportsPaths`.
+- **PR зелений, push червоний**  
+  Перевірити **New Code Definition** і довести покриття/дублікації на "new code".