public void TestValidation()
{
bool lExecuted = false;
var clm = new CommandLineManager();
clm.AddOptionRequiresData("L", "List out the operation.", (clmanager) => lExecuted = true);
clm.AddValidation((manager) => false);
clm.Execute(new[] { "-L", "Data" });
Assert.IsFalse(lExecuted);
// Change it to true. We can do this because the `LastOption` is still set.
clm.AddValidation((manager) => true);
clm.Execute(new[] { "-L", "Data" });
Assert.IsTrue(lExecuted);
}