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");
        }