diff --git a/Source/MQTTnet/Diagnostics/MqttNetLogMessage.cs b/Source/MQTTnet/Diagnostics/MqttNetLogMessage.cs
index 1ab1b4c..285dc00 100644
--- a/Source/MQTTnet/Diagnostics/MqttNetLogMessage.cs
+++ b/Source/MQTTnet/Diagnostics/MqttNetLogMessage.cs
@@ -2,7 +2,7 @@
 
 namespace MQTTnet.Diagnostics
 {
-    public class MqttNetLogMessage
+    public sealed class MqttNetLogMessage
     {
         public string LogId { get; set; }
 
diff --git a/Tests/MQTTnet.Core.Tests/Mockups/TestEnvironment.cs b/Tests/MQTTnet.Core.Tests/Mockups/TestEnvironment.cs
index e2d15fd..8a36cd1 100644
--- a/Tests/MQTTnet.Core.Tests/Mockups/TestEnvironment.cs
+++ b/Tests/MQTTnet.Core.Tests/Mockups/TestEnvironment.cs
@@ -46,7 +46,10 @@ namespace MQTTnet.Tests.Mockups
 
             ServerLogger.LogMessagePublished += (s, e) =>
             {
-                Debug.WriteLine(e.LogMessage.ToString());
+                if (Debugger.IsAttached)
+                {
+                    Debug.WriteLine(e.LogMessage.ToString());
+                }
 
                 if (e.LogMessage.Level == MqttNetLogLevel.Error)
                 {
@@ -59,7 +62,10 @@ namespace MQTTnet.Tests.Mockups
 
             ClientLogger.LogMessagePublished += (s, e) =>
             {
-                Debug.WriteLine(e.LogMessage.ToString());
+                if (Debugger.IsAttached)
+                {
+                    Debug.WriteLine(e.LogMessage.ToString());
+                }
 
                 if (e.LogMessage.Level == MqttNetLogLevel.Error)
                 {
diff --git a/Tests/MQTTnet.Core.Tests/Mockups/TestServerWrapper.cs b/Tests/MQTTnet.Core.Tests/Mockups/TestServerWrapper.cs
index 4ed83d8..1c651aa 100644
--- a/Tests/MQTTnet.Core.Tests/Mockups/TestServerWrapper.cs
+++ b/Tests/MQTTnet.Core.Tests/Mockups/TestServerWrapper.cs
@@ -135,6 +135,7 @@ namespace MQTTnet.Tests.Mockups
 
         public void Dispose()
         {
+            Implementation.Dispose();
         }
     }
 }
\ No newline at end of file
diff --git a/Tests/MQTTnet.Core.Tests/Server_Tests.cs b/Tests/MQTTnet.Core.Tests/Server_Tests.cs
index 3df7751..7d6a117 100644
--- a/Tests/MQTTnet.Core.Tests/Server_Tests.cs
+++ b/Tests/MQTTnet.Core.Tests/Server_Tests.cs
@@ -15,6 +15,7 @@ using System.Linq;
 using System.Text;
 using System.Threading;
 using System.Threading.Tasks;
+using MQTTnet.Diagnostics;
 using MQTTnet.Formatter;
 
 namespace MQTTnet.Tests