public void Export_DownloadQnA()
{
IExportService <QnAMakerSetting> exportService = new ExportServiceImpl <QnAMakerSetting>();
var controller = new ListingController(queryService.Object, exportService);
var result = controller.ExportQnAMaker(string.Empty, AppDomain.CurrentDomain.BaseDirectory);
Assert.IsNotNull(result);
Assert.IsInstanceOfType(result, typeof(FileResult));
var fileResult = result as FileResult;
Assert.IsTrue(fileResult.ContentType == "application/text");
}