New test common project for database connections using the settings.json (#210)

* moved test driver tests and test common classes to separate projects

test/Microsoft.SqlTools.ServiceLayer.Test.Common/SelfCleaningTempFile.cs

@@ -0,0 +1,53 @@
+//
+// Copyright (c) Microsoft. All rights reserved.
+// Licensed under the MIT license. See LICENSE file in the project root for full license information.
+//
+
+using System;
+using System.IO;
+
+namespace Microsoft.SqlTools.ServiceLayer.Test.Common
+{
+    public class SelfCleaningTempFile : IDisposable
+    {
+        private bool disposed;
+
+        public SelfCleaningTempFile()
+        {
+            FilePath = Path.GetTempFileName();
+        }
+
+        public string FilePath { get; private set; }
+
+        #region IDisposable Implementation
+
+        public void Dispose()
+        {
+            if (!disposed)
+            {
+                Dispose(true);
+                GC.SuppressFinalize(this);
+            }
+        }
+
+        public void Dispose(bool disposing)
+        {
+            if (!disposed && disposing)
+            {
+                try
+                {
+                    File.Delete(FilePath);
+                }
+                catch
+                {
+                    Console.WriteLine($"Failed to cleanup {FilePath}");
+                }
+            }
+
+            disposed = true;
+        }
+
+        #endregion
+
+    }
+}