public void CalculatesAnnualCosts(decimal annualPrice, decimal pricePerUnit, decimal consumptionThreshold, decimal unitsPerYear, decimal expectedCost)
{
var cut = new PackagedTariff("Product B", annualPrice, pricePerUnit, consumptionThreshold);
var c = new Consumption(unitsPerYear);
var actualCost = cut.Calculate(c);
Assert.AreEqual(expectedCost, actualCost);
}
