public void TestScenarioA_NoPromotions_Applied()
{
SetProductQuantity('A', 1);
SetProductQuantity('B', 1);
SetProductQuantity('C', 1);
promotionEngine.ApplyPromotions(activePromotions, productCart);
Assert.False(promotionEngine.IsPromoApplied);
Assert.AreEqual(0, promotionEngine.DiscountedAmount);
}