public void GetDiscount_WhenAccumulatedDiscountIsEqualToLimit_ReturnsAccumulatedDiscount()
{
const int limit = 20;
var rule = new AccumulatedDiscountLimitRule(limit);
var transaction = GetTransaction("2019-10-13");
var discount = rule.GetDiscount(transaction, limit);
Assert.Equal(limit, discount);
}
public void GetDiscount_WhenTransactionsAreOnSameMonth_LimitsAccumulatedDiscount()
{
const int limit = 20;
var rule = new AccumulatedDiscountLimitRule(limit);
var transaction1 = GetTransaction("2019-10-13");
var transaction2 = GetTransaction("2019-10-14");
var transaction3 = GetTransaction("2019-10-20");
var discount1 = rule.GetDiscount(transaction1, 10);
var discount2 = rule.GetDiscount(transaction2, 7);
var discount3 = rule.GetDiscount(transaction3, 20);
Assert.Equal(10, discount1);
Assert.Equal(7, discount2);
Assert.Equal(3, discount3);
}
public void GetDiscount_WhenTransactionsAreOnDifferentMonths_LimitsByMonth()
{
const int limit = 20;
var rule = new AccumulatedDiscountLimitRule(limit);
var firstMonthTransaction1 = GetTransaction("2019-10-13");
var firstMonthTransaction2 = GetTransaction("2019-10-14");
var secondMonthTransaction1 = GetTransaction("2019-11-10");
var secondMonthTransaction2 = GetTransaction("2019-11-20");
var discount1 = rule.GetDiscount(firstMonthTransaction1, 10);
var discount2 = rule.GetDiscount(firstMonthTransaction2, 9);
var discount3 = rule.GetDiscount(secondMonthTransaction1, 19);
var discount4 = rule.GetDiscount(secondMonthTransaction2, 30);
Assert.Equal(10, discount1);
Assert.Equal(9, discount2);
Assert.Equal(19, discount3);
Assert.Equal(1, discount4);
}
public void GetDiscount_WhenTransactionIsNull_ThrowsArgumentNullException()
{
var rule = new AccumulatedDiscountLimitRule(20);
Assert.Throws <ArgumentNullException>("transaction", () => rule.GetDiscount(null, 10));
}
