MQTTnet/Tests/MQTTnet.Core.Tests/MqttFactoryTests.cs

using Microsoft.VisualStudio.TestTools.UnitTesting;
using MQTTnet.Diagnostics;
using MQTTnet.Extensions.ManagedClient;
using System;
using System.Threading;
using System.Threading.Tasks;

namespace MQTTnet.Tests
{
    [TestClass]
    public class MqttFactoryTests
    {
        [TestMethod]
        public async Task Create_Managed_Client_With_Logger()
        {
            var factory = new MqttFactory();

            //This test compares
            //1. correct logID
            string logId = "logId";
            bool invalidLogIdOccured = false;

            //2. if the total log calls are the same for global and local
            int globalLogCount = 0;
            int localLogCount = 0;

            MqttNetLogger logger = new MqttNetLogger(logId);

            //we have a theoretical bug here if a concurrent test is also logging
            var globalLog = new EventHandler<MqttNetLogMessagePublishedEventArgs>((s, e) =>
            {
                if (logId != e.TraceMessage.LogId)
                {
                    invalidLogIdOccured = true;
                }
                Interlocked.Increment(ref globalLogCount);
            });

            MqttNetGlobalLogger.LogMessagePublished += globalLog;

            logger.LogMessagePublished += (s, e) =>
            {
                if (logId != e.TraceMessage.LogId)
                {
                    invalidLogIdOccured = true;
                }
                Interlocked.Increment(ref localLogCount);
            };

            var managedClient = factory.CreateManagedMqttClient(logger);
            try
            {
                var clientOptions = new ManagedMqttClientOptionsBuilder();

                clientOptions.WithClientOptions(o => o.WithTcpServer("this_is_an_invalid_host").WithCommunicationTimeout(TimeSpan.FromSeconds(1)));

                //try connect to get some log entries
                await managedClient.StartAsync(clientOptions.Build());

                //wait at least connect timeout or we have some log messages
                var tcs = new TaskCompletionSource<object>();
                managedClient.ConnectingFailed += (s, e) => tcs.TrySetResult(null);
                await Task.WhenAny(Task.Delay(managedClient.Options.ClientOptions.CommunicationTimeout), tcs.Task);
            }
            finally
            {
                MqttNetGlobalLogger.LogMessagePublished -= globalLog;

                await managedClient.StopAsync();
            }

            Assert.IsFalse(invalidLogIdOccured);
            Assert.AreNotEqual(0, globalLogCount);
            Assert.AreEqual(globalLogCount, localLogCount);
        }
    }
}