Unit Tests doesn´t work properly

Hi, I´m trying to write a test Class in a legacy asp.net web application. It has been written in .net framework v2.0. When I try to run the tests nothing happens.

Here my code:

using System;
using Megawork.InformacaoGerencial.BLL;
using Microsoft.VisualStudio.TestTools.UnitTesting;
 
 
 
/// <summary>
/// Summary description for TestClass
/// </summary>
[TestClass]
public class TesteUtilitario
{
        public TesteUtilitario()
        {
                //
                // TODO: Add constructor logic here
                //
        }
    [TestMethod]
    public  void TestarFormula()
    {
        decimal resultado = 0;
        resultado = Util.FormulaDoExcel(25.000m, 26.565m);
        Assert.IsNotNull(resultado);
    }
}

the class above is inside a folder in the App_Code folder in my asp.net application.