test: Add CommunicationSequence

S7.Net.UnitTest/Framework/IsExternalInit.cs

@@ -0,0 +1,7 @@
+using System.ComponentModel;
+
+namespace System.Runtime.CompilerServices
+{
+    [EditorBrowsable(EditorBrowsableState.Never)]
+    internal record IsExternalInit;
+}

S7.Net.UnitTest/Infrastructure/CommunicationSequence.cs

@@ -0,0 +1,82 @@
+using System;
+using System.Buffers;
+using System.Collections;
+using System.Collections.Generic;
+using System.Linq;
+using System.Net;
+using System.Net.Sockets;
+using System.Threading.Tasks;
+
+namespace S7.Net.UnitTest;
+
+internal class CommunicationSequence : IEnumerable<RequestResponsePair>
+{
+    private readonly List<RequestResponsePair> _requestResponsePairs = new List<RequestResponsePair>();
+
+    public CommunicationSequence()
+    {
+        
+    }
+
+    public void Add(string requestPattern, string responsePattern)
+    {
+        _requestResponsePairs.Add(new RequestResponsePair(requestPattern, responsePattern));
+    }
+
+    public IEnumerator<RequestResponsePair> GetEnumerator()
+    {
+        return _requestResponsePairs.GetEnumerator();
+    }
+
+    IEnumerator IEnumerable.GetEnumerator() => GetEnumerator();
+
+    public Task Serve(out int port)
+    {
+        var socket = CreateBoundListenSocket(out port);
+        socket.Listen(0);
+
+        async Task Impl()
+        {
+            await Task.Yield();
+            var socketIn = socket.Accept();
+
+            var buffer = ArrayPool<byte>.Shared.Rent(1024);
+            try
+            {
+                foreach (var pair in _requestResponsePairs)
+                {
+                    var bytesReceived = socketIn.Receive(buffer, SocketFlags.None);
+
+                    var received = buffer.Take(bytesReceived).ToArray();
+                    Console.WriteLine($"=> {BitConverter.ToString(received)}");
+
+                    var response = Responder.Respond(pair, received);
+
+                    Console.WriteLine($"<= {BitConverter.ToString(response)}");
+                    socketIn.Send(response);
+                }
+            }
+            finally
+            {
+                ArrayPool<byte>.Shared.Return(buffer);
+            }
+
+            socketIn.Close();
+        }
+
+        return Impl();
+    }
+
+    private static Socket CreateBoundListenSocket(out int port)
+    {
+        var socket = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
+        var endpoint = new IPEndPoint(IPAddress.Loopback, 0);
+
+        socket.Bind(endpoint);
+
+        var localEndpoint = (IPEndPoint)socket.LocalEndPoint!;
+        port = localEndpoint.Port;
+
+        return socket;
+    }
+}

S7.Net.UnitTest/Infrastructure/RequestResponsePair.cs

@@ -0,0 +1,3 @@
+namespace S7.Net.UnitTest;
+
+internal record RequestResponsePair(string RequestPattern, string ResponsePattern);

S7.Net.UnitTest/Infrastructure/Responder.cs

@@ -0,0 +1,80 @@
+using System;
+using System.Collections.Generic;
+using System.Globalization;
+using System.IO;
+
+namespace S7.Net.UnitTest;
+
+internal static class Responder
+{
+    private const string Comment = "//";
+    private static char[] Space = " ".ToCharArray();
+
+    public static byte[] Respond(RequestResponsePair pair, byte[] request)
+    {
+        var offset = 0;
+        var matches = new Dictionary<string, byte>();
+        var res = new List<byte>();
+        using var requestReader = new StringReader(pair.RequestPattern);
+
+        string line;
+        while ((line = requestReader.ReadLine()) != null)
+        {
+            var tokens = line.Split(Space, StringSplitOptions.RemoveEmptyEntries);
+            foreach (var token in tokens)
+            {
+                if (token.StartsWith(Comment)) break;
+
+                if (offset >= request.Length)
+                {
+                    throw new Exception("Request pattern has more data than request.");
+                }
+
+                var received = request[offset];
+
+                if (token.Length == 2 && byte.TryParse(token, NumberStyles.HexNumber, CultureInfo.InvariantCulture, out var value))
+                {
+                    // Number, exact match
+                    if (value != received)
+                    {
+                        throw new Exception($"Incorrect data at offset {offset}. Expected {value:X2}, received {received:X2}.");
+                    }
+                }
+                else
+                {
+                    matches[token] = received;
+                }
+
+                offset++;
+            }
+        }
+
+        if (offset != request.Length) throw new Exception("Request contained more data than request pattern.");
+
+        using var responseReader = new StringReader(pair.ResponsePattern);
+        while ((line = responseReader.ReadLine()) != null)
+        {
+            var tokens = line.Split(Space, StringSplitOptions.RemoveEmptyEntries);
+            foreach (var token in tokens)
+            {
+                if (token.StartsWith(Comment)) break;
+
+                if (token.Length == 2 && byte.TryParse(token, NumberStyles.HexNumber, CultureInfo.InvariantCulture, out var value))
+                {
+                    res.Add(value);
+                }
+                else
+                {
+                    if (!matches.TryGetValue(token, out var match))
+                    {
+                        throw new Exception($"Unmatched token '{token}' in response.");
+                    }
+
+                    res.Add(match);
+                }
+            }
+        }
+
+        return res.ToArray();
+    }
+}

S7.Net.UnitTest/S7.Net.UnitTest.csproj

@@ -8,6 +8,7 @@
   </PropertyGroup>
 
   <PropertyGroup>
+    <LangVersion>latest</LangVersion>
     <SignAssembly>true</SignAssembly>
     <AssemblyOriginatorKeyFile>Properties\S7.Net.snk</AssemblyOriginatorKeyFile>
     <IsPackable>false</IsPackable>