public void Apply_WithLessThanMinimumProductForPromotionToBeAvailed_NoPromotionApplied()
    {
        IList <IProduct> products = SetupProduct("ProductA", 50, 2);

        var promotion           = new Promotion.PromotionA();
        var totalValueOfProduct = promotion.Apply(products);

        Assert.Equal(100, totalValueOfProduct);
    }
    public void Apply_WithMoreThanMinimumProductForPromotionToBeAvailed_PromotionAppliedForRelevantProducts()
    {
        IList <IProduct> products = SetupProduct("ProductA", 50, 5);

        var promotion           = new Promotion.PromotionA();
        var totalValueOfProduct = promotion.Apply(products);

        Assert.Equal(230, totalValueOfProduct);
    }