public void TestDiscount()
{
terminal.SetPricing('A', 1.00, Tuple.Create(3, 3.0));
terminal.ScanProduct('A');
terminal.ApplyDiscount(0.2);
var expectedTotal = 0.8;
var actualTotal = terminal.CalculateTotal();
Assert.AreEqual(expectedTotal, actualTotal, delta: expectedTotal / 100);
}