MQTTnet/Source/MQTTnet.Tests/Formatter/MqttPacketWriter_Tests.cs

using MQTTnet.Exceptions;
using MQTTnet.Formatter;

namespace MQTTnet.Tests.Formatter;

// ReSharper disable InconsistentNaming
[TestClass]
public sealed class MqttPacketWriter_Tests
{
    [TestMethod]
    public void Reset_After_Usage()
    {
        var writer = new MqttBufferWriter(4096, 65535);
        writer.WriteString("AString");
        writer.WriteByte(0x1);
        writer.WriteByte(0x0);
        writer.WriteByte(0x1);
        writer.WriteVariableByteInteger(1234U);
        writer.WriteVariableByteInteger(9876U);

        writer.Reset(0);

        Assert.AreEqual(0, writer.Length);
    }

    [TestMethod]
    public void Use_All_Data_Types()
    {
        var writer = new MqttBufferWriter(4096, 65535);
        writer.WriteString("AString");
        writer.WriteByte(0x1);
        writer.WriteByte(0x0);
        writer.WriteByte(0x1);
        writer.WriteVariableByteInteger(1234U);
        writer.WriteVariableByteInteger(9876U);

        var buffer = writer.GetBuffer();

        var reader = new MqttBufferReader();
        reader.SetBuffer(buffer, 0, writer.Length);

        Assert.AreEqual("AString", reader.ReadString());
        Assert.AreEqual(1, reader.ReadByte());
        Assert.AreEqual(0, reader.ReadByte());
        Assert.AreEqual(1, reader.ReadByte());
        Assert.AreEqual(1234U, reader.ReadVariableByteInteger());
        Assert.AreEqual(9876U, reader.ReadVariableByteInteger());
    }

    [TestMethod]
    public void Throw_If_String_Too_Long()
    {
        Assert.ThrowsExactly<MqttProtocolViolationException>(() =>
        {
            var writer = new MqttBufferWriter(4096, 65535);

            writer.WriteString(string.Empty.PadLeft(65536));
        });
    }

    [TestMethod]
    public void Write_And_Read_Multiple_Times()
    {
        var writer = new MqttBufferWriter(4096, 65535);
        writer.WriteString("A relative short string.");
        writer.WriteBinary(new byte[1234]);
        writer.WriteByte(0x01);
        writer.WriteByte(0x02);
        writer.WriteVariableByteInteger(5647382);
        writer.WriteString("A relative short string.");
        writer.WriteVariableByteInteger(8574489);
        writer.WriteBinary(new byte[48]);
        writer.WriteByte(2);
        writer.WriteByte(0x02);
        writer.WriteString("fjgffiogfhgfhoihgoireghreghreguhreguireoghreouighreouighreughreguiorehreuiohruiorehreuioghreug");
        writer.WriteBinary(new byte[3]);

        var readPayload = new ArraySegment<byte>(writer.GetBuffer(), 0, writer.Length).ToArray();

        var reader = new MqttBufferReader();
        reader.SetBuffer(readPayload, 0, readPayload.Length);

        for (var i = 0; i < 100000; i++)
        {
            reader.Seek(0);

            reader.ReadString();
            reader.ReadBinaryData();
            reader.ReadByte();
            reader.ReadByte();
            reader.ReadVariableByteInteger();
            reader.ReadString();
            reader.ReadVariableByteInteger();
            reader.ReadBinaryData();
            reader.ReadByte();
            reader.ReadByte();
            reader.ReadString();
            reader.ReadBinaryData();
        }
    }
}