SortCases.cs

public class CustomConvention : Convention
{
    public CustomConvention()
    {
        Classes
          .NameEndsWith("Tests");

        Cases
          .Where(method => method.IsVoid());

        ClassExecution
          .CreateInstancePerTestClass()
          .SortCases((caseA, caseB) => String.Compare(caseA.Name, caseB.Name, StringComparison.Ordinal));
    }
}