My suggestion would be to use Unit Tests.
In your application do the following switches in Program.cs:
#if DEBUG
public class Program
#else
class Program
#endif
and the same for static Main(string[] args).
Or alternatively use Friend Assemblies by adding
[assembly: InternalsVisibleTo("TestAssembly")]
to your AssemblyInfo.cs.
Then create a unit test project and a test that looks a bit like so:
[TestClass]
public class TestApplication
{
[TestMethod]
public void TestMyArgument()
{
using (var sw = new StringWriter())
{
Console.SetOut(sw); // this makes any Console.Writes etc go to sw
Program.Main(new[] { "argument" });
var result = sw.ToString();
Assert.AreEqual("expected", result);
}
}
}
This way you can, in an automated way, test multiple inputs of arguments without having to edit your code or change a menu setting every time you want to check something different.