acdream/tests/AcDream.Core.Net.Tests/NetClientTests.cs

using System.Net;
using AcDream.Core.Net;

namespace AcDream.Core.Net.Tests;

public class NetClientTests
{
    [Fact]
    public void SendReceive_LoopbackSelfTest_EchoRoundTrip()
    {
        // Two NetClients on loopback that send messages to each other.
        // Proves Send + Receive actually work end-to-end over real UDP
        // without depending on any remote server.
        using var serverSide = new NetClient(new IPEndPoint(IPAddress.Loopback, 0));
        using var clientSide = new NetClient(new IPEndPoint(IPAddress.Loopback, serverSide.LocalEndPoint.Port));

        byte[] outbound = { 0xDE, 0xAD, 0xBE, 0xEF };
        clientSide.Send(outbound);

        var received = serverSide.Receive(TimeSpan.FromSeconds(2), out var from);

        Assert.NotNull(received);
        Assert.Equal(outbound, received);
        Assert.NotNull(from);
        Assert.Equal(IPAddress.Loopback, from!.Address);
        Assert.Equal(clientSide.LocalEndPoint.Port, from.Port);
    }

    [Fact]
    public void Receive_Timeout_ReturnsNullAndNoException()
    {
        // Listen for something that will never arrive; the timeout path
        // must return null cleanly rather than leaking a SocketException.
        using var client = new NetClient(new IPEndPoint(IPAddress.Loopback, 1));
        var result = client.Receive(TimeSpan.FromMilliseconds(100), out var from);
        Assert.Null(result);
        Assert.Null(from);
    }
}