Updates to the unit tests

Author: niemyjski

Source/Tests/Properties/AssemblyInfo.cs

@@ -1,6 +1,8 @@
 using System;
 using System.Reflection;
 using System.Runtime.InteropServices;
+using Xunit;
 
 [assembly: AssemblyTitle("Client.Tests")]
-[assembly: Guid("9e6c83c2-2024-4892-a667-11221c758a9e")]
+[assembly: Guid("9e6c83c2-2024-4892-a667-11221c758a9e")]
+[assembly: CollectionBehavior(DisableTestParallelization = true)]