public async void ServerRespectsMaxClientConnectionLimit()
{
// Arrange
var endpoint = EndpointSource.GetNext();
using var server = new ModbusTcpServer()
{
MaxConnections = 2
};
server.Start(endpoint);
// Act
var client1 = new ModbusTcpClient();
var client2 = new ModbusTcpClient();
var client3 = new ModbusTcpClient();
await Task.Run(() =>
{
client1.Connect(endpoint);
client1.WriteSingleRegister(0, 2, 3);
client2.Connect(endpoint);
client2.WriteSingleRegister(0, 2, 3);
client3.Connect(endpoint);
try
{
client3.WriteSingleRegister(0, 2, 3);
throw new Exception("Modbus TCP server accepts too many clients.");
}
// Windows
catch (IOException) { }
// Linux
catch (InvalidOperationException) { }
server.MaxConnections = 3;
client3.Connect(endpoint);
client3.WriteSingleRegister(0, 2, 3);
});
// Assert
}
public void CanReadMaximumNumberOfRegisters()
{
// Arrange
var endpoint = EndpointSource.GetNext();
var server = new ModbusTcpServer();
server.Start(endpoint);
var client = new ModbusTcpClient();
client.Connect(endpoint);
// Act
client.ReadHoldingRegisters <ushort>(0, 0, 125);
client.ReadInputRegisters <ushort>(0, 0, 125);
}
public async void ServerHandlesMultipleClients()
{
// Arrange
var endpoint = EndpointSource.GetNext();
using var server = new ModbusTcpServer();
server.Start(endpoint);
// Act
var clients = Enumerable.Range(0, 20).Select(index => new ModbusTcpClient()).ToList();
var tasks = clients.Select((client, index) =>
{
var data = Enumerable.Range(0, 20).Select(i => (float)i).ToArray();
client.Connect(endpoint);
_logger.WriteLine($"Client {index}: Connected.");
return(Task.Run(async() =>
{
_logger.WriteLine($"Client {index}: Task started.");
for (int i = 0; i < 10; i++)
{
client.ReadHoldingRegisters <short>(0, 0, 100);
_logger.WriteLine($"Client {index}: ReadHoldingRegisters({i})");
await Task.Delay(50);
client.WriteMultipleRegisters(0, 0, data);
_logger.WriteLine($"Client {index}: WriteMultipleRegisters({i})");
await Task.Delay(50);
client.ReadCoils(0, 0, 25);
_logger.WriteLine($"Client {index}: ReadCoils({i})");
await Task.Delay(50);
client.ReadInputRegisters <float>(0, 0, 20);
_logger.WriteLine($"Client {index}: ReadInputRegisters({i})");
await Task.Delay(50);
}
client.Disconnect();
}));
}).ToList();
await Task.WhenAll(tasks);
// Assert
}
public void ThrowsWhenWritingTooManyRegisters()
{
// Arrange
var endpoint = EndpointSource.GetNext();
using var server = new ModbusTcpServer();
server.Start(endpoint);
var client = new ModbusTcpClient();
client.Connect(endpoint);
// Act
Action action = () => client.WriteMultipleRegisters <ushort>(0, 0, new ushort[124]);
// Assert
Assert.Throws <ModbusException>(action);
}
public void ThrowsIfZeroBytesAreRequested()
{
// Arrange
var endpoint = EndpointSource.GetNext();
using var server = new ModbusTcpServer();
server.Start(endpoint);
var client = new ModbusTcpClient();
client.Connect(endpoint);
// Act
Action action = () => client.ReadHoldingRegisters <byte>(0, 0, 0);
// Assert
Assert.Throws <ModbusException>(action);
}
public void ThrowsIfOddNumberOfBytesIsRequested()
{
// Arrange
var endpoint = EndpointSource.GetNext();
using var server = new ModbusTcpServer();
server.Start(endpoint);
var client = new ModbusTcpClient();
client.Connect(endpoint);
// Act
Action action = () => client.ReadHoldingRegisters <byte>(0, 0, 3);
// Assert
Assert.Throws <ArgumentOutOfRangeException>(action);
}
public void ThrowsWhenReadingTooManyRegisters()
{
// Arrange
var endpoint = EndpointSource.GetNext();
using var server = new ModbusTcpServer();
server.Start(endpoint);
var client = new ModbusTcpClient();
client.Connect(endpoint);
// Act
Action action1 = () => client.ReadHoldingRegisters <ushort>(0, 0, 126);
Action action2 = () => client.ReadInputRegisters <ushort>(0, 0, 126);
// Assert
Assert.Throws <ModbusException>(action1);
Assert.Throws <ModbusException>(action2);
}
public void ArraySizeIsCorrectForBooleanInput()
{
// Arrange
var endpoint = EndpointSource.GetNext();
using var server = new ModbusTcpServer();
server.Start(endpoint);
var client = new ModbusTcpClient();
client.Connect(endpoint);
// Act
var actual = client.ReadHoldingRegisters <bool>(0, 0, 10).ToArray().Count();
// Assert
var expected = 10;
Assert.True(actual == expected);
}
public async Task FC023Test()
{
// Arrange
var endpoint = EndpointSource.GetNext();
using var server = new ModbusTcpServer();
server.Start(endpoint);
void AsyncWorkaround()
{
var buffer = server.GetHoldingRegisterBuffer <float>();
buffer[6] = 65.455F;
buffer[7] = 24;
buffer[8] = 25;
}
lock (server.Lock)
{
AsyncWorkaround();
}
var client = new ModbusTcpClient();
client.Connect(endpoint);
// Act
var actual1 = await client.ReadWriteMultipleRegistersAsync <float, float>(0, 2, 10, 12, new float[] { 1.211F });
// Assert
var expected = new float[] { 0, 0, 0, 0, 0, 1.211F, 24, 25, 0, 0 };
Assert.True(expected.SequenceEqual(actual1.ToArray()));
lock (server.Lock)
{
var actual2 = server.GetHoldingRegisterBuffer <float>().Slice(1, 10).ToArray();
Assert.True(expected.SequenceEqual(actual2));
}
}
public async void ServerWorksWithExternalTcpClient()
{
// Arrange
var endpoint = EndpointSource.GetNext();
var listener = new TcpListener(endpoint);
using var server = new ModbusTcpServer();
var client = new ModbusTcpClient();
var expected = new double[] { 0.1, 0.2, 0.3, 0.4, 0.5 };
double[] actual = null;
// Act
listener.Start();
var clientTask = Task.Run(() =>
{
client.Connect(endpoint);
actual = client
.ReadWriteMultipleRegisters <double, double>(0, 0, 5, 0, expected)
.ToArray();
client.Disconnect();
});
var serverTask = Task.Run(() =>
{
var tcpClient = listener.AcceptTcpClient();
server.Start(tcpClient);
});
await clientTask;
// Assert
Assert.True(actual.SequenceEqual(expected));
}
public void BigEndianWritePerformanceTest()
{
// Arrange
var endpoint = EndpointSource.GetNext();
using var server = new ModbusTcpServer();
server.Start(endpoint);
var buffer = server.GetHoldingRegisters();
// Act
var sw = Stopwatch.StartNew();
for (int i = 0; i < 1_000_000; i++)
{
buffer.SetBigEndian(address: 1, 12334234.0);
}
// Assert
var elapsed = sw.Elapsed;
_logger.WriteLine($"Time per 1000 write operations: {elapsed.TotalMilliseconds / 1000} ms");
}
public void FC16Test()
{
// Arrange
var endpoint = EndpointSource.GetNext();
using var server = new ModbusTcpServer();
server.Start(endpoint);
var client = new ModbusTcpClient();
client.Connect(endpoint);
// Act
client.WriteMultipleRegisters(0, 2, _array);
// Assert
var expected = _array;
lock (server.Lock)
{
var actual = server.GetHoldingRegisterBuffer <float>().Slice(1, 10);
Assert.True(expected.SequenceEqual(actual.ToArray()));
}
}
public void HandlesBigEndian()
{
// Arrange
var endpoint = EndpointSource.GetNext();
using var server = new ModbusTcpServer();
server.Start(endpoint);
var client = new ModbusTcpClient();
client.Connect(endpoint, ModbusEndianness.BigEndian);
// Act
client.WriteMultipleRegisters(0, 0, new int[] { 0x20302020, 0x40101010, 0x11220000 });
// Assert
var expected = new int[] { 0x20203020, 0x10101040, 0x00002211 };
lock (server.Lock)
{
var actual = server.GetHoldingRegisterBuffer <int>().Slice(0, 3);
Assert.True(expected.SequenceEqual(actual.ToArray()));
}
}
