public void IndexReturnsAViewResultWithAListOfDiscount()
{
var mock = new Mock <IDiscountRepository>();
mock.Setup(repo => repo.GetAll()).Returns(GetTestDiscounts());
var controller = new DiscountController(mock.Object);
var result = controller.Index();
var viewResult = Xunit.Assert.IsType <ViewResult>(result);
var model = Xunit.Assert.IsAssignableFrom <IEnumerable <Discount> >(viewResult.Model);
Xunit.Assert.Equal(GetTestDiscounts().Count, model.Count());
}