prove its broken

Source/MQTTnet/Client/MqttClient.cs

@@ -25,8 +25,8 @@ namespace MQTTnet.Client
 
         private IMqttClientOptions _options;
         private CancellationTokenSource _cancellationTokenSource;
-        private Task _packetReceiverTask;
-        private Task _keepAliveMessageSenderTask;
+        internal Task _packetReceiverTask;
+        internal Task _keepAliveMessageSenderTask;
         private IMqttChannelAdapter _adapter;
         private bool _cleanDisconnectInitiated;
         private TaskCompletionSource<bool> _disconnectReason;

Source/MQTTnet/Properties/AssemblyInfo.cs

@@ -0,0 +1,3 @@
+using System.Runtime.CompilerServices;
+
+[assembly:InternalsVisibleTo("MQTTnet.Core.Tests")]

Tests/MQTTnet.Core.Tests/MqttClientTests.cs

@@ -1,9 +1,13 @@
 using System;
 using System.Net.Sockets;
+using System.Threading;
 using System.Threading.Tasks;
 using Microsoft.VisualStudio.TestTools.UnitTesting;
+using MQTTnet.Adapter;
 using MQTTnet.Client;
+using MQTTnet.Diagnostics;
 using MQTTnet.Exceptions;
+using MQTTnet.Packets;
 
 namespace MQTTnet.Core.Tests
 {
@@ -35,5 +39,37 @@ namespace MQTTnet.Core.Tests
             Assert.IsInstanceOfType(ex, typeof(MqttCommunicationException));
             Assert.IsInstanceOfType(ex.InnerException, typeof(SocketException));
         }
+
+        [TestMethod]
+        public async Task ClientCleanupOnAuthentificationFails()
+        {
+            var channel = new TestMqttCommunicationAdapter();
+            var channel2 = new TestMqttCommunicationAdapter();
+            channel.Partner = channel2;
+            channel2.Partner = channel;
+
+            Task.Run(async () => {
+                var connect = await channel2.ReceivePacketAsync(TimeSpan.Zero, CancellationToken.None);
+                await channel2.SendPacketAsync(new MqttConnAckPacket() { ConnectReturnCode = Protocol.MqttConnectReturnCode.ConnectionRefusedNotAuthorized }, CancellationToken.None);
+            });
+
+
+            
+            var fake = new TestMqttCommunicationAdapterFactory(channel);
+
+            var client = new MqttClient(fake, new MqttNetLogger());
+            
+            try
+            {
+                await client.ConnectAsync(new MqttClientOptionsBuilder().WithTcpServer("any-server").Build());
+            }
+            catch (Exception ex)
+            {
+                Assert.IsInstanceOfType(ex, typeof(MqttConnectingFailedException));
+            }
+
+            Assert.IsTrue(client._packetReceiverTask == null || client._packetReceiverTask.IsCompleted, "receive loop not completed");
+            Assert.IsTrue(client._keepAliveMessageSenderTask == null || client._keepAliveMessageSenderTask.IsCompleted, "keepalive loop not completed");
+        }
     }
 }