mostalive
89a1158c93
Domain-only field: OrderDto and OrderData stay without it; the stored row keeps the original total after saving a discounted order. The discount percentage is not copied (derivable). yak: exercise-1-solution-on-branch-exercise-1-solution-4s5q
60 lines
2.4 KiB
C#
60 lines
2.4 KiB
C#
using After;
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using static BeforeAfter.Tests.TestData.ClientBuilder;
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using static BeforeAfter.Tests.TestData.OrderBuilder;
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namespace BeforeAfter.Tests;
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/// <summary>
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/// EXERCISE — the mapping from a <see cref="DiscountedOrder"/> onto an
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/// <see cref="Order"/> is NOT one-on-one. (This is the solution participants
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/// arrive at from the stub in EXERCISE.md.)
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/// </summary>
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public class DiscountedOrderMappingTests
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{
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[Fact] // EXERCISE STEP 2
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public void A_discounted_order_can_be_correlated_onto_its_order()
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{
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var db = new DbContext();
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var order = ValidOrder().WithDescription("big order").WithTotal(150_00).Build();
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var client = ValidClient().WithName("Acme").WithOrder(order).Build();
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db.Save(client);
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db.Save(order);
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// 10 % for orders above €100:
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var discounted = DiscountCalculator.CalculateDiscount(
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order, discountBarrierCents: 100_00, discountPercentage: 10);
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// Correlate: the discounted result belongs to the order carrying this id.
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Assert.Equal(order.Id, discounted.OrderId);
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// Copy the discounted total onto the order. The discount percentage is
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// deliberately NOT copied — it is derivable from the two totals.
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order.DiscountedTotalInCents = discounted.DiscountedTotalInCents;
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Assert.Equal(135_00, order.DiscountedTotalInCents);
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}
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[Fact] // EXERCISE STEP 3
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public void Saving_a_discounted_order_keeps_the_stored_total_untouched()
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{
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var db = new DbContext();
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var order = ValidOrder().WithDescription("big order").WithTotal(150_00).Build();
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var client = ValidClient().WithName("Acme").WithOrder(order).Build();
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db.Save(client);
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db.Save(order);
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var discounted = DiscountCalculator.CalculateDiscount(
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order, discountBarrierCents: 100_00, discountPercentage: 10);
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Assert.Equal(order.Id, discounted.OrderId);
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order.DiscountedTotalInCents = discounted.DiscountedTotalInCents;
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// Save the updated order: the context refreshes the stored row in place.
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db.Save(order);
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// The persisted record keeps the ORIGINAL total: the database knows
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// nothing about discounts — derived data lives in the domain only.
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var row = db.Find<OrderData>(candidate => candidate.Id == discounted.OrderId)!;
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Assert.Equal(150_00, row.TotalInCents);
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}
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}
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