public void Execute() { var parser = new FluentCommandLineParser(); IDirectory mega = null; parser.Setup <string>('i', "inputDir") .WithDescription("Path to the extracted mega SSPG package folder") .Callback(x => mega = FileSystem.ParseDirectory(x)); var result = parser.Parse(Options); if (result.HelpCalled) { return; } Assert.IsTrue(mega.Exists, $"The folder does not exist: {mega}"); PackageHelper.DecompressMegaPackage(mega, mega); }