Add tests to improve code coverage (#187)

* DbColumn and ReliableConnection tests

* More retry connection tests

* More tests

* Fix broken peek definition integration tests

* Fix test bug

* Add a couple batch tests

* Add some more tests

* More tests for code coverage.

* Validation and Diagnostic tests

* A few more tests

* A few mote test changes.

* Update file path tests to run on Windows only

src/Microsoft.SqlTools.ServiceLayer/QueryExecution/Batch.cs

@@ -48,7 +48,7 @@ namespace Microsoft.SqlTools.ServiceLayer.QueryExecution
         /// <summary>
         /// Internal representation of the messages so we can modify internally
         /// </summary>
-        private readonly List<ResultMessage> resultMessages;
+        internal readonly List<ResultMessage> resultMessages;
 
         /// <summary>
         /// Internal representation of the result sets so we can modify internally
@@ -379,7 +379,7 @@ namespace Microsoft.SqlTools.ServiceLayer.QueryExecution
         /// </summary>
         /// <param name="sender">Sender of the event</param>
         /// <param name="args">Arguments for the event</param>
-        private void StatementCompletedHandler(object sender, StatementCompletedEventArgs args)
+        internal void StatementCompletedHandler(object sender, StatementCompletedEventArgs args)
         {
             // Add a message for the number of rows the query returned
             string message;
@@ -414,7 +414,7 @@ namespace Microsoft.SqlTools.ServiceLayer.QueryExecution
         /// cannot be converted to SqlException, the message is written to the messages list.
         /// </summary>
         /// <param name="dbe">The exception to unwrap</param>
-        private void UnwrapDbException(DbException dbe)
+        internal void UnwrapDbException(DbException dbe)
         {
             SqlException se = dbe as SqlException;
             if (se != null)