Weighing: Add Gassner scale and update tests

Elwig/Helpers/Extensions.cs

@@ -0,0 +1,63 @@
+using System.IO;
+using System.Runtime.InteropServices;
+using System.Threading.Tasks;
+
+namespace Elwig.Helpers {
+    static partial class Extensions {
+
+        [LibraryImport("msvcrt.dll")]
+        [UnmanagedCallConv(CallConvs = [typeof(System.Runtime.CompilerServices.CallConvCdecl)])]
+        private static unsafe partial int memcmp(void* b1, void* b2, long count);
+
+        public static unsafe int CompareBuffers(char[] buffer1, int offset1, char[] buffer2, int offset2, int count) {
+            fixed (char* b1 = buffer1, b2 = buffer2) {
+                return memcmp(b1 + offset1, b2 + offset2, count);
+            }
+        }
+
+        public static string? ReadUntil(this StreamReader reader, string delimiter) {
+            return ReadUntil(reader, delimiter.ToCharArray());
+        }
+
+        public static string? ReadUntil(this StreamReader reader, char delimiter) {
+            return ReadUntil(reader, new char[] { delimiter });
+        }
+
+        public static string? ReadUntil(this StreamReader reader, char[] delimiter) {
+            var buf = new char[512];
+            int bufSize = 0, ret;
+            while (!reader.EndOfStream && bufSize < buf.Length - 1) {
+                if ((ret = reader.Read()) == -1)
+                    return null;
+                buf[bufSize++] = (char)ret;
+
+                if (bufSize >= delimiter.Length && CompareBuffers(buf, bufSize - delimiter.Length, delimiter, 0, delimiter.Length) == 0)
+                    return new string(buf, 0, bufSize);
+            }
+            return null;
+        }
+
+        public static Task<string?> ReadUntilAsync(this StreamReader reader, string delimiter) {
+            return ReadUntilAsync(reader, delimiter.ToCharArray());
+        }
+
+        public static Task<string?> ReadUntilAsync(this StreamReader reader, char delimiter) {
+            return ReadUntilAsync(reader, new char[] { delimiter });
+        }
+
+        public static async Task<string?> ReadUntilAsync(this StreamReader reader, char[] delimiter) {
+            var buf = new char[512];
+            int bufSize = 0;
+            var tmpBuf = new char[1];
+            while (!reader.EndOfStream && bufSize < buf.Length - 1) {
+                if ((await reader.ReadAsync(tmpBuf, 0, 1)) != 1)
+                    return null;
+                buf[bufSize++] = tmpBuf[0];
+
+                if (bufSize >= delimiter.Length && CompareBuffers(buf, bufSize - delimiter.Length, delimiter, 0, delimiter.Length) == 0)
+                    return new string(buf, 0, bufSize);
+            }
+            return null;
+        }
+    }
+}

Elwig/Helpers/Weighing/AveryEventScale.cs

@@ -26,6 +26,8 @@ namespace Elwig.Helpers.Weighing {
             Model = model;
             IsReady = true;
             HasFillingClearance = false;
+            Stream.WriteTimeout = -1;
+            Stream.ReadTimeout = -1;
             BackgroundThread = new Thread(new ParameterizedThreadStart(BackgroundLoop));
             BackgroundThread.Start();
         }
@@ -46,7 +48,8 @@ namespace Elwig.Helpers.Weighing {
             while (IsRunning) {
                 try {
                     var data = await Receive();
-                    RaiseWeighingEvent(new WeighingEventArgs(data));
+                    if (data != null)
+                        RaiseWeighingEvent(new WeighingEventArgs(data.Value));
                 } catch (Exception ex) {
                     MessageBox.Show($"Beim Wiegen ist ein Fehler Aufgetreten:\n\n{ex.Message}", "Waagenfehler",
                         MessageBoxButton.OK, MessageBoxImage.Error);
@@ -54,13 +57,12 @@ namespace Elwig.Helpers.Weighing {
             }
         }
 
-        protected async Task<WeighingResult> Receive() {
+        protected async Task<WeighingResult?> Receive() {
-            string? line = null;
+            var line = await Reader.ReadUntilAsync("\r\n");
-            using (var reader = new StreamReader(Stream, Encoding.ASCII, false, -1, true)) {
+            if (LogPath != null) await File.AppendAllTextAsync(LogPath, line);
-                line = await reader.ReadLineAsync();
+            if (line == null || line == "") {
-                if (LogPath != null) await File.AppendAllTextAsync(LogPath, $"{line}\r\n");
+                return null;
-            }
+            } else if (line.Length != 35 || line[0] != ' ' || line[9] != ' ' || line[15] != ' ' || line[20] != ' ' || line[32] != ' ') {
-            if (line == null || line.Length != 33 || line[0] != ' ' || line[9] != ' ' || line[15] != ' ' || line[20] != ' ' || line[32] != ' ') {
                 throw new IOException($"Invalid event from scale: '{line}'");
             }
 

Elwig/Helpers/Weighing/GassnerScale.cs

@@ -0,0 +1,122 @@
+using System;
+using System.IO;
+using System.IO.Ports;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace Elwig.Helpers.Weighing {
+    public class GassnerScale : Scale, ICommandScale {
+
+        public string Manufacturer => "Gassner";
+        public int InternalScaleNr => 1;
+        public string Model { get; private set; }
+        public string ScaleId { get; private set; }
+        public bool IsReady { get; private set; }
+        public bool HasFillingClearance { get; private set; }
+
+        public GassnerScale(string id, string model, string cnx, string? empty = null, string? filling = null, int? limit = null, string? log = null) :
+          base(cnx, empty, filling, limit, log) {
+            ScaleId = id;
+            Model = model;
+            IsReady = true;
+            HasFillingClearance = false;
+            Stream.WriteTimeout = 250;
+            Stream.ReadTimeout = 11000;
+        }
+
+        protected Task SendCommand(char command) => SendCommand(Convert.ToByte(command));
+
+        protected async Task SendCommand(byte command) {
+            byte[] cmd = [command];
+            await Stream.WriteAsync(cmd);
+            if (LogPath != null) await File.AppendAllTextAsync(LogPath, Encoding.ASCII.GetString(cmd));
+        }
+
+        protected async Task<string> ReceiveResponse() {
+            var line = await Reader.ReadUntilAsync('\x03');
+            if (LogPath != null) await File.AppendAllTextAsync(LogPath, $"{line}\r\n");
+            if (line == null || line.Length < 4 || !line.StartsWith('\x02')) {
+                throw new IOException("Invalid response from scale");
+            }
+
+            var status = line[1..3];
+            if (status[0] == 'E' || status[1] != 'S') {
+                string msg = $"Unbekannter Fehler (Fehler code {status})";
+                switch (status[1]) {
+                    case 'M': msg = "Waage in Bewegung"; break;
+                }
+                throw new IOException($"Waagenfehler {status}: {msg}");
+            } else if (status[0] != ' ') {
+                throw new IOException($"Invalid response from scale (error code {status})");
+            }
+
+            return line[1..^1];
+        }
+
+        protected async Task<WeighingResult> Weigh(bool incIdentNr) {
+            await SendCommand(incIdentNr ? '\x05' : '?');
+            string record = await ReceiveResponse();
+            if (record.Length != 45)
+                throw new IOException("Invalid response from scale: Received record has invalid size");
+            var line = record[2..];
+
+            var status  = line[ 0.. 2];
+            var brutto  = line[ 2.. 9].Trim();
+            var tara    = line[ 9..16].Trim();
+            var netto   = line[16..23].Trim();
+            var scaleNr = line[23..25].Trim();
+            var identNr = line[25..31].Trim();
+            var date    = line[31..39];
+            var time    = line[39..45];
+
+            identNr = identNr.Length > 0 && identNr != "0" ? identNr : null;
+            var parsedDate = DateOnly.ParseExact(date, "yyyyMMdd");
+            return new() {
+                Weight = int.Parse(netto),
+                WeighingId = identNr,
+                FullWeighingId = identNr,
+                Date = parsedDate,
+                Time = TimeOnly.ParseExact(time, "HHmmss"),
+            };
+        }
+
+        public async Task<WeighingResult> Weigh() {
+            return await Weigh(true);
+        }
+
+        public async Task<WeighingResult> GetCurrentWeight() {
+            return await Weigh(false);
+        }
+
+        public async Task Empty() {
+            SerialPort? p = ControlSerialEmpty ?? Serial;
+            if (EmptyMode == Output.RTS && p != null) {
+                p.RtsEnable = true;
+                await Task.Delay(EmptyDelay);
+                p.RtsEnable = false;
+            } else if (EmptyMode == Output.DTR && p != null) {
+                p.DtrEnable = true;
+                await Task.Delay(EmptyDelay);
+                p.DtrEnable = false;
+            }
+        }
+
+        protected Task SetFillingClearance(bool status) {
+            SerialPort? p = ControlSerialFilling ?? Serial;
+            if (FillingClearanceMode == Output.RTS && p != null) {
+                p.RtsEnable = status;
+            } else if (FillingClearanceMode == Output.DTR && p != null) {
+                p.DtrEnable = status;
+            }
+            return Task.CompletedTask;
+        }
+
+        public async Task GrantFillingClearance() {
+            await SetFillingClearance(true);
+        }
+
+        public async Task RevokeFillingClearance() {
+            await SetFillingClearance(false);
+        }
+    }
+}

Elwig/Helpers/Weighing/Scale.cs

@@ -2,6 +2,7 @@
 using System.IO;
 using System.Net.Sockets;
 using System;
+using System.Text;
 
 namespace Elwig.Helpers.Weighing {
     public abstract class Scale : IDisposable {
@@ -12,6 +13,7 @@ namespace Elwig.Helpers.Weighing {
         protected SerialPort? ControlSerialEmpty = null, ControlSerialFilling = null;
         protected TcpClient? Tcp = null;
         protected Stream Stream;
+        protected StreamReader Reader;
 
         protected readonly Output? EmptyMode = null;
         protected readonly Output? FillingClearanceMode = null;
@@ -26,6 +28,8 @@ namespace Elwig.Helpers.Weighing {
                 return new SysTecITScale(config.Id, config.Model!, config.Connection!, config.Empty, config.Filling, limit, config.Log);
             } else if (config.Type == "Avery-Async") {
                 return new AveryEventScale(config.Id, config.Model!, config.Connection!, config.Empty, config.Filling, limit, config.Log);
+            } else if (config.Type == "Gassner") {
+                return new GassnerScale(config.Id, config.Model!, config.Connection!, config.Empty, config.Filling, limit, config.Log);
             } else {
                 throw new ArgumentException($"Invalid scale type: \"{config.Type}\"");
             }
@@ -41,6 +45,7 @@ namespace Elwig.Helpers.Weighing {
             } else {
                 throw new ArgumentException($"Unsupported scheme: \"{cnx.Split(':')[0]}\"");
             }
+            Reader = new(Stream, Encoding.ASCII, false, 512);
 
             LogPath = log;
 
@@ -73,6 +78,7 @@ namespace Elwig.Helpers.Weighing {
         }
 
         public void Dispose() {
+            Reader.Close();
             Stream.Close();
             Serial?.Close();
             ControlSerialEmpty?.Close();

Elwig/Helpers/Weighing/SysTecITScale.cs

@@ -31,12 +31,9 @@ namespace Elwig.Helpers.Weighing {
         }
 
         protected async Task<string> ReceiveResponse() {
-            string? line = null;
+            var line = await Reader.ReadUntilAsync("\r\n");
-            using (var reader = new StreamReader(Stream, Encoding.ASCII, false, -1, true)) {
+            if (LogPath != null) await File.AppendAllTextAsync(LogPath, line);
-                line = await reader.ReadLineAsync();
+            if (line == null || line.Length < 4 || !line.StartsWith('<') || !line.EndsWith(">\r\n")) {
-                if (LogPath != null) await File.AppendAllTextAsync(LogPath, $"{line}\r\n");
-            }
-            if (line == null || line.Length < 4 || !line.StartsWith('<') || !line.EndsWith('>')) {
                 throw new IOException("Invalid response from scale");
             }
 
@@ -68,7 +65,7 @@ namespace Elwig.Helpers.Weighing {
                 throw new IOException($"Invalid response from scale (error code {error})");
             }
 
-            return line[1..^1];
+            return line[1..^3];
         }
 
         protected async Task<WeighingResult> Weigh(bool incIdentNr) {
@@ -82,7 +79,7 @@ namespace Elwig.Helpers.Weighing {
             var date       = line[ 2..10];
             var time       = line[10..15];
             var identNr    = line[15..19].Trim();
-            var scaleNr    = line[19..20];
+            var scaleNr    = line[19..20].Trim();
             var brutto     = line[20..28].Trim();
             var tara       = line[28..36].Trim();
             var netto      = line[36..44].Trim();

Tests/WeighingTests/MockScale.cs

@@ -1,6 +1,7 @@
 using System.Net.Sockets;
 using System.Net;
 using System.Text;
+using System.IO;
 
 namespace Tests.WeighingTests {
     public abstract class MockScale : IDisposable {
@@ -63,9 +64,46 @@ namespace Tests.WeighingTests {
     }
 
     public class EventMockScale : MockScale {
+
+        private readonly Func<int, string?, int, (string, bool)> Handler;
+        private readonly Thread ServerThread;
+        private TcpClient? Client;
+        private bool IsRunning = true;
+
         public EventMockScale(int port, Func<int, string?, int, (string, bool)> handler) :
             base(port) {
-            // TODO
+            Handler = handler;
+            ServerThread = new Thread(new ParameterizedThreadStart(Serve));
+            ServerThread.Start();
+        }
+
+        private async void Serve(object? parameters) {
+            while (IsRunning) {
+                try {
+                    Client = await Server.AcceptTcpClientAsync();
+                } catch (Exception) {
+                    // ignore
+                }
+            }
+        }
+
+        public async Task Weigh(int weight) {
+            Weight = weight;
+            await Weigh();
+        }
+
+        public async Task Weigh() {
+            var (res, inc) = Handler(Weight, Error, IdentNr + 1);
+            if (inc) IdentNr++;
+            await Client!.GetStream().WriteAsync(Encoding.ASCII.GetBytes(res));
+        }
+
+        public new void Dispose() {
+            Client?.Dispose();
+            IsRunning = false;
+            ServerThread.Interrupt();
+            ServerThread.Join();
+            base.Dispose();
         }
     }
 }

Tests/WeighingTests/ScaleTestBadenL320.cs

@@ -0,0 +1,70 @@
+using Elwig.Helpers.Weighing;
+
+namespace Tests.WeighingTests {
+    [TestFixture]
+    public class ScaleTestBadenL320 {
+
+        private EventMockScale? Mock;
+        private AveryEventScale? Scale;
+
+        private static (string, bool) ScaleHandler(int weight, string? error, int identNr) {
+            var modes = error?.Split(';') ?? [];
+            var invalid = modes.Contains("invalid");
+            var unit = modes.Contains("unit");
+
+            if (invalid) {
+                return ("abcd\r\n", false);
+            }
+
+            bool incr = true;
+            return ($" {new DateTime(2020, 9, 28, 9, 8, 0):dd.MM.yy HH:mm} {identNr,4} {weight,9}{(unit ? "lb" : "kg")} \r\n", incr);
+        }
+
+        [OneTimeSetUp]
+        public void SetupScale() {
+            Mock = new EventMockScale(12345, ScaleHandler);
+            Scale = new("1", "L320", "tcp://127.0.0.1:12345");
+        }
+
+        [OneTimeTearDown]
+        public void TeardownScale() {
+            Mock?.Dispose();
+            Scale?.Dispose();
+        }
+
+        [SetUp]
+        public void ResetScale() {
+            Mock!.IdentNr = 0;
+            Mock!.Weight = 0;
+            Mock!.Error = null;
+        }
+
+        [Test]
+        public async Task Test_01_Normal() {
+            WeighingResult? res = null;
+            Scale!.WeighingEvent += (sender, evt) => {
+                res = evt.Result;
+            };
+
+            await Mock!.Weigh(2345);
+            await Task.Delay(100);
+            Assert.That(res, Is.Not.Null);
+            Assert.That(res, Is.EqualTo(new WeighingResult {
+                Weight = 2345, WeighingId = "1",
+                FullWeighingId = $"2020-09-28/1",
+                Date = new DateOnly(2020, 9, 28), Time = new TimeOnly(9, 8),
+            }));
+
+            await Mock!.Weigh(4215);
+            await Task.Delay(100);
+            Assert.That(res, Is.Not.Null);
+            Assert.That(res, Is.EqualTo(new WeighingResult {
+                Weight = 4215,
+                WeighingId = "2",
+                FullWeighingId = $"2020-09-28/2",
+                Date = new DateOnly(2020, 9, 28),
+                Time = new TimeOnly(9, 8),
+            }));
+        }
+    }
+}

Tests/WeighingTests/ScaleTestGrInzersdorfL246.cs

@@ -0,0 +1,144 @@
+using Elwig.Helpers.Weighing;
+
+namespace Tests.WeighingTests {
+    [TestFixture]
+    class ScaleTestGrInzersdorfL246 {
+
+        private MockScale? Mock;
+        private SysTecITScale? Scale;
+
+        private static (string, bool) ScaleHandler(string req, int weight, string? error, int identNr) {
+            var modes = error?.Split(';') ?? [];
+            var overloaded = modes.Contains("overloaded");
+            var moving = modes.Contains("moving");
+            var invalid = modes.Contains("invalid");
+            var crc = modes.Contains("crc");
+            var unit = modes.Contains("unit");
+
+            if (invalid) {
+                return ("abcd\r\n", false);
+            } else if (!req.StartsWith('<') || !req.EndsWith('>')) {
+                return ("<31>\r\n", false);
+            }
+            req = req[1..^1];
+
+            bool incr;
+            if (req.Length > 3) {
+                return ("<32>\r\n", false);
+            } else if (req.StartsWith("RN")) {
+                incr = true;
+            } else if (req.StartsWith("RM")) {
+                incr = false;
+            } else {
+                return ("<32>\r\n", false);
+            }
+
+            if (overloaded)
+                return ("<12>\r\n", false);
+
+            if (moving && incr)
+                return ("<13>\r\n", false);
+
+            string data = $"00{(moving ? 1 : 0)}0{new DateTime(2020, 10, 17, 14, 23, 0):dd.MM.yyHH:mm}{(incr ? identNr : 0),4}1" +
+                $"{weight,8}{0,8}{weight,8}{(unit ? "lb" : "kg")}   {"001",3}";
+            ushort checksum = Elwig.Helpers.Utils.CalcCrc16Modbus(data);
+            if (crc) checksum += 10;
+            return ($"<{data}{checksum,8}>\r\n", incr);
+        }
+
+        [OneTimeSetUp]
+        public void SetupScale() {
+            Mock = new CommandMockScale(12345, ScaleHandler);
+            Scale = new("1", "L246", "tcp://127.0.0.1:12345");
+        }
+
+        [OneTimeTearDown]
+        public void TeardownScale() {
+            Mock?.Dispose();
+            Scale?.Dispose();
+        }
+
+        [SetUp]
+        public void ResetScale() {
+            Mock!.IdentNr = 0;
+            Mock!.Weight = 0;
+            Mock!.Error = null;
+        }
+
+        [Test]
+        public async Task Test_01_CurrentWeight() {
+            Mock!.Weight = 1235;
+            Assert.That(await Scale!.GetCurrentWeight(), Is.EqualTo(new WeighingResult {
+                Weight = 1235, Date = new DateOnly(2020, 10, 17), Time = new TimeOnly(14, 23),
+            }));
+            Mock!.Weight = 1240;
+            Assert.That(await Scale!.GetCurrentWeight(), Is.EqualTo(new WeighingResult {
+                Weight = 1240, Date = new DateOnly(2020, 10, 17), Time = new TimeOnly(14, 23),
+            }));
+            Mock!.Weight = 1245;
+            Assert.That(await Scale!.GetCurrentWeight(), Is.EqualTo(new WeighingResult {
+                Weight = 1245, Date = new DateOnly(2020, 10, 17), Time = new TimeOnly(14, 23),
+            }));
+        }
+
+        [Test]
+        public async Task Test_02_Normal() {
+            Mock!.Weight = 1235;
+            Assert.That(await Scale!.Weigh(), Is.EqualTo(new WeighingResult {
+                Weight = 1235, WeighingId = "1",
+                FullWeighingId = $"2020-10-17/1",
+                Date = new DateOnly(2020, 10, 17), Time = new TimeOnly(14, 23),
+            }));
+            Mock!.Weight = 3335;
+            Assert.That(await Scale!.Weigh(), Is.EqualTo(new WeighingResult {
+                Weight = 3335, WeighingId = "2",
+                FullWeighingId = $"2020-10-17/2",
+                Date = new DateOnly(2020, 10, 17), Time = new TimeOnly(14, 23),
+            }));
+            Mock!.Weight = 6420;
+            Assert.That(await Scale!.Weigh(), Is.EqualTo(new WeighingResult {
+                Weight = 6420, WeighingId = "3",
+                FullWeighingId = $"2020-10-17/3",
+                Date = new DateOnly(2020, 10, 17), Time = new TimeOnly(14, 23),
+            }));
+        }
+
+        [Test]
+        public void Test_03_Moving() {
+            Mock!.Weight = 1_000;
+            Mock!.Error = "moving";
+            IOException ex = Assert.ThrowsAsync<IOException>(async () => await Scale!.Weigh());
+            Assert.That(ex.Message, Contains.Substring("Waage in Bewegung"));
+        }
+
+        [Test]
+        public void Test_04_Overloaded() {
+            Mock!.Weight = 10_000;
+            Mock!.Error = "overloaded";
+            IOException ex = Assert.ThrowsAsync<IOException>(async () => await Scale!.Weigh());
+            Assert.That(ex.Message, Contains.Substring("Waage in Überlast"));
+        }
+
+        [Test]
+        public void Test_05_InvalidResponse() {
+            Mock!.Weight = 1_000;
+            Mock!.Error = "invalid";
+            Assert.ThrowsAsync<IOException>(async () => await Scale!.Weigh());
+        }
+
+        [Test]
+        public void Test_06_InvalidCrc() {
+            Mock!.Weight = 1_000;
+            Mock!.Error = "crc";
+            IOException ex = Assert.ThrowsAsync<IOException>(async () => await Scale!.Weigh());
+            Assert.That(ex.Message, Contains.Substring("Invalid CRC16 checksum"));
+        }
+
+        [Test]
+        public void Test_07_InvalidUnit() {
+            Mock!.Weight = 1_000;
+            Mock!.Error = "unit";
+            IOException ex = Assert.ThrowsAsync<IOException>(async () => await Scale!.Weigh());
+        }
+    }
+}

Tests/WeighingTests/ScaleTestHaugsdorf.cs

@@ -1,6 +1,6 @@
 namespace Tests.WeighingTests {
     [TestFixture]
-    public class ScaleTestWolkersdorf {
+    public class ScaleTestHaugsdorf {
         // TODO
     }
 }

Tests/WeighingTests/ScaleTestMatzenIT3000A.cs

@@ -2,7 +2,7 @@
 
 namespace Tests.WeighingTests {
     [TestFixture]
-    class ScaleTestMatzen {
+    class ScaleTestMatzenIT3000A {
 
         private MockScale? Mock;
         private SysTecITScale? Scale;
@@ -43,7 +43,7 @@ namespace Tests.WeighingTests {
                 return ("<13>\r\n", false);
 
             string data = $"00{(moving ? 1 : 0)}0{new DateTime(2020, 10, 15, 12, 34, 0):dd.MM.yyHH:mm}{(incr ? identNr : 0),4}1" +
-                $"{weight,8}{0,8}{weight,8}{(unit ? "lb" : "kg")}   {1,3}";
+                $"{weight,8}{0,8}{weight,8}{(unit ? "lb" : "kg")}   {"1",3}";
             ushort checksum = Elwig.Helpers.Utils.CalcCrc16Modbus(data);
             if (crc) checksum += 10;
             return ($"<{data}{checksum,8}>\r\n", incr);

Tests/WeighingTests/ScaleTestSitzendorf.cs

@@ -1,6 +1,6 @@
 namespace Tests.WeighingTests {
     [TestFixture]
-    public class ScaleTestGrInzersdorf {
+    public class ScaleTestSitzendorf {
         // TODO
     }
 }

Tests/WeighingTests/ScaleTestWolkersdorfIT6000E.cs

@@ -0,0 +1,163 @@
+using Elwig.Helpers.Weighing;
+
+namespace Tests.WeighingTests {
+    [TestFixture]
+    class ScaleTestWolkersdorfIT6000E {
+
+        private MockScale? MockA;
+        private MockScale? MockB;
+        private SysTecITScale? ScaleA;
+        private SysTecITScale? ScaleB;
+
+        private static (string, bool) ScaleHandler(string req, int weight, string? error, int identNr, string terminalNr) {
+            var modes = error?.Split(';') ?? [];
+            var overloaded = modes.Contains("overloaded");
+            var moving = modes.Contains("moving");
+            var invalid = modes.Contains("invalid");
+            var crc = modes.Contains("crc");
+            var unit = modes.Contains("unit");
+
+            if (invalid) {
+                return ("abcd\r\n", false);
+            } else if (!req.StartsWith('<') || !req.EndsWith('>')) {
+                return ("<31>\r\n", false);
+            }
+            req = req[1..^1];
+
+            bool incr;
+            if (req.Length > 3) {
+                return ("<32>\r\n", false);
+            } else if (req.StartsWith("RN")) {
+                incr = true;
+            } else if (req.StartsWith("RM")) {
+                incr = false;
+            } else {
+                return ("<32>\r\n", false);
+            }
+
+            if (overloaded)
+                return ("<12>\r\n", false);
+
+            if (moving && incr)
+                return ("<13>\r\n", false);
+
+            string data = $"00{(moving ? 1 : 0)}0{new DateTime(2020, 10, 8, 8, 47, 0):dd.MM.yyHH:mm}{(incr ? identNr : 0),4}1" +
+                $"{weight,8}{0,8}{weight,8}{(unit ? "lb" : "kg")}   {terminalNr,3}";
+            ushort checksum = Elwig.Helpers.Utils.CalcCrc16Modbus(data);
+            if (crc) checksum += 10;
+            return ($"<{data}{checksum,8}>\r\n", incr);
+        }
+
+        [OneTimeSetUp]
+        public void SetupScale() {
+            MockA = new CommandMockScale(12345, (req, weight, error, identNr) => ScaleHandler(req, weight, error, identNr, "A"));
+            MockB = new CommandMockScale(12346, (req, weight, error, identNr) => ScaleHandler(req, weight, error, identNr, "B"));
+            ScaleA = new("A", "IT3000E", "tcp://127.0.0.1:12345");
+            ScaleB = new("B", "IT3000E", "tcp://127.0.0.1:12346");
+        }
+
+        [OneTimeTearDown]
+        public void TeardownScale() {
+            MockA?.Dispose();
+            MockB?.Dispose();
+            ScaleA?.Dispose();
+            ScaleB?.Dispose();
+        }
+
+        [SetUp]
+        public void ResetScale() {
+            MockA!.IdentNr = 0;
+            MockA!.Weight = 0;
+            MockA!.Error = null;
+            MockB!.IdentNr = 0;
+            MockB!.Weight = 0;
+            MockB!.Error = null;
+        }
+
+        [Test]
+        public async Task Test_01_CurrentWeight() {
+            MockA!.Weight = 1234;
+            Assert.That(await ScaleA!.GetCurrentWeight(), Is.EqualTo(new WeighingResult {
+                Weight = 1234, Date = new DateOnly(2020, 10, 8), Time = new TimeOnly(8, 47),
+            }));
+            MockB!.Weight = 3456;
+            Assert.That(await ScaleB!.GetCurrentWeight(), Is.EqualTo(new WeighingResult {
+                Weight = 3456, Date = new DateOnly(2020, 10, 8), Time = new TimeOnly(8, 47),
+            }));
+            MockA!.Weight = 1236;
+            Assert.That(await ScaleA!.GetCurrentWeight(), Is.EqualTo(new WeighingResult {
+                Weight = 1236, Date = new DateOnly(2020, 10, 8), Time = new TimeOnly(8, 47),
+            }));
+            MockB!.Weight = 3457;
+            Assert.That(await ScaleB!.GetCurrentWeight(), Is.EqualTo(new WeighingResult {
+                Weight = 3457, Date = new DateOnly(2020, 10, 8), Time = new TimeOnly(8, 47),
+            }));
+        }
+
+        [Test]
+        public async Task Test_02_Normal() {
+            MockA!.Weight = 1234;
+            Assert.That(await ScaleA!.Weigh(), Is.EqualTo(new WeighingResult {
+                Weight = 1234, WeighingId = "1",
+                FullWeighingId = $"2020-10-08/1",
+                Date = new DateOnly(2020, 10, 8), Time = new TimeOnly(8, 47),
+            }));
+            MockB!.Weight = 3456;
+            Assert.That(await ScaleB!.Weigh(), Is.EqualTo(new WeighingResult {
+                Weight = 3456, WeighingId = "1",
+                FullWeighingId = $"2020-10-08/1",
+                Date = new DateOnly(2020, 10, 8), Time = new TimeOnly(8, 47),
+            }));
+            MockA!.Weight = 4321;
+            Assert.That(await ScaleA!.Weigh(), Is.EqualTo(new WeighingResult {
+                Weight = 4321, WeighingId = "2",
+                FullWeighingId = $"2020-10-08/2",
+                Date = new DateOnly(2020, 10, 8), Time = new TimeOnly(8, 47),
+            }));
+            MockB!.Weight = 3333;
+            Assert.That(await ScaleB!.Weigh(), Is.EqualTo(new WeighingResult {
+                Weight = 3333, WeighingId = "2",
+                FullWeighingId = $"2020-10-08/2",
+                Date = new DateOnly(2020, 10, 8), Time = new TimeOnly(8, 47),
+            }));
+        }
+
+        [Test]
+        public void Test_03_Moving() {
+            MockA!.Weight = 1_000;
+            MockA!.Error = "moving";
+            IOException ex = Assert.ThrowsAsync<IOException>(async () => await ScaleA!.Weigh());
+            Assert.That(ex.Message, Contains.Substring("Waage in Bewegung"));
+        }
+
+        [Test]
+        public void Test_04_Overloaded() {
+            MockA!.Weight = 10_000;
+            MockA!.Error = "overloaded";
+            IOException ex = Assert.ThrowsAsync<IOException>(async () => await ScaleA!.Weigh());
+            Assert.That(ex.Message, Contains.Substring("Waage in Überlast"));
+        }
+
+        [Test]
+        public void Test_05_InvalidResponse() {
+            MockA!.Weight = 1_000;
+            MockA!.Error = "invalid";
+            Assert.ThrowsAsync<IOException>(async () => await ScaleA!.Weigh());
+        }
+
+        [Test]
+        public void Test_06_InvalidCrc() {
+            MockA!.Weight = 1_000;
+            MockA!.Error = "crc";
+            IOException ex = Assert.ThrowsAsync<IOException>(async () => await ScaleA!.Weigh());
+            Assert.That(ex.Message, Contains.Substring("Invalid CRC16 checksum"));
+        }
+
+        [Test]
+        public void Test_07_InvalidUnit() {
+            MockA!.Weight = 1_000;
+            MockA!.Error = "unit";
+            IOException ex = Assert.ThrowsAsync<IOException>(async () => await ScaleA!.Weigh());
+        }
+    }
+}