added perf tests using test driver (#136)

* added perf tests using test driver

test/Microsoft.SqlTools.ServiceLayer.TestDriver/Utility/TestTimer.cs

@@ -0,0 +1,59 @@
+//
+// 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.Globalization;
+
+namespace Microsoft.SqlTools.ServiceLayer.TestDriver.Utility
+{
+    /// <summary>
+    /// Timer to calculate the test run time
+    /// </summary>
+    public class TestTimer
+    {
+        public TestTimer()
+        {
+            Start();
+        }
+
+        public void Start()
+        {
+            StartDateTime = DateTime.UtcNow;
+        }
+
+        public void End()
+        {
+            EndDateTime = DateTime.UtcNow;
+        }
+
+        public void EndAndPrint(string testName)
+        {
+            End();
+            var currentColor = Console.ForegroundColor;
+            Console.ForegroundColor = ConsoleColor.Green;
+            Console.WriteLine(string.Format(CultureInfo.InvariantCulture, "Test Name: {0} Run time in milliSeconds: {1}", testName, TotalMilliSeconds));
+            Console.ForegroundColor = currentColor;
+        }
+
+        public double TotalMilliSeconds
+        {
+            get
+            {
+                return (EndDateTime - StartDateTime).TotalMilliseconds;
+            }
+        }
+
+        public double TotalMilliSecondsUntilNow
+        {
+            get
+            {
+                return (DateTime.UtcNow - StartDateTime).TotalMilliseconds;
+            }
+        }
+
+        public DateTime StartDateTime { get; private set; }
+        public DateTime EndDateTime { get; private set; }
+    }
+}