OnAfterTestListCompleted is not getting invoked after the Test List execution

I have followed the steps mentioned in http://www.telerik.com/automated-testing-tools/support/documentation/user-guide/code-samples/general/execution-extensions.aspx

Create a Class Library
Added the necesssary references

Below is the Code:
It is the same as given in the above link.

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.IO;
using System.Data;
using System.Data.OleDb;
using System.Windows.Forms;
using ArtOfTest.WebAii.Design.Execution;

namespace ClassLibrary1
{
    public class Class1 : IExecutionExtension
    {
        public void OnAfterTestCompleted(ExecutionContext executionContext, TestResult result)
        {
            
        }

        public void OnBeforeTestStarted(ExecutionContext executionContext, ArtOfTest.WebAii.Design.ProjectModel.Test test)
        {
            
        }

        public DataTable OnInitializeDataSource(ExecutionContext executionContext)
        {
            return null;
        }

        public void OnStepFailure(ExecutionContext executionContext, ArtOfTest.WebAii.Design.AutomationStepResult stepResult)
        {
           
        }

        public void OnAfterTestListCompleted(RunResult result)
        {
            string msg = string.Format("TestList '{0}' completed on '{1}'. ({2}/{3}) Passed", result.Name, result.EndTime, result.PassedCount, result.TestResults.Count);
            StreamWriter file = new StreamWriter("c:\\test-list-results.txt");
            file.WriteLine(msg);
            file.Close();
        }

        public void OnBeforeTestListStarted(TestList list)
        {
           
        }
    }
}