UnitTest_WithAssertObject.cs

  [Test]
  public void ApplyBlackFridayDiscount_Should_ApplyBlackFridayDiscount_When_CalledOnNewProduct()
  {
      // given
      var product = CreateProduct(basePrice: 100);

      // when
      product.ApplyBlackFridayDiscount();

      // then
      var productShould = new ProductAssert(product);
      productShould
          .BeAvailable()
          .HaveDiscount("Black Friday", 20)
          .Cost(80);
  }