Visual Studio Test Explorer does not find the tests

I'm having a problem with Visual Studio 2013, Test Explorer is not loading the tests at any time, either after Build or through Run Tests / CTRL+R, T . Does anyone have any clue what that might be?

I have the following packages installed through NuGet: xUnit.net , xUnit.net: Runners , Fluent Assertions , and the test below as an example:

using Xunit;
namespace Registro
{
    public class CadastroValidoRecebido
    {
        [Fact]
        public void Usuario_Adicionado_Ao_Sistema()
        {

        }
    }
}

I followed the links of several links, what seemed most promising were the processor architecture changes reported in the link below, but Test Explorer still does not find the tests.

link