OrderLine + computed TotalInCents; both inbound mappers reconstruct a one-line order from the flat DTO/row (derived data is re-derived, not written); builder realises WithTotal as a single line. Outbound mappers, DTO, OrderData, DbContext and WebApp untouched — the small-steps payoff. yak: exercise-2-solution-on-branch-exercise-2-solution-hw7e
57 lines
1.8 KiB
C#
57 lines
1.8 KiB
C#
using After;
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namespace BeforeAfter.Tests.TestData;
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/// <summary>
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/// Test data builder for an <see cref="Order"/> (TestDataBuilder pattern).
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/// <see cref="ValidOrder"/> starts from a <em>fresh</em> order —
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/// <see cref="Guid.Empty"/> id, empty description, zero total, exactly what
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/// <c>new Order()</c> gives — and every <c>With...</c> returns the builder for
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/// chaining; <see cref="Build"/> hands back the order.
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///
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/// This class is the only place tests touch an order's *construction*: when
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/// the domain evolves (e.g. OrderLines making the total computed), only these
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/// internals change and the tests keep reading the same.
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/// </summary>
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public sealed class OrderBuilder
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{
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private readonly Order _order = new();
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private int? _totalInCents;
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/// <summary>A valid, fresh order — the neutral starting point for tests.</summary>
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public static OrderBuilder ValidOrder() => new();
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public OrderBuilder WithId(Guid id)
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{
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_order.Id = id;
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return this;
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}
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public OrderBuilder WithDescription(string description)
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{
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_order.Description = description;
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return this;
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}
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/// <summary>
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/// Sets the total in cents (<c>150_00</c> = €150.00). Since OrderLines
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/// arrived, the total is computed — the requested total is realised in
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/// <see cref="Build"/> as a single line carrying the order's description,
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/// so <c>WithDescription</c>/<c>WithTotal</c> work in any order. This API
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/// stayed identical across that domain evolution; only these internals
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/// changed.
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/// </summary>
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public OrderBuilder WithTotal(int totalInCents)
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{
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_totalInCents = totalInCents;
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return this;
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}
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public Order Build()
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{
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if (_totalInCents is int total)
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_order.Lines.Add(new OrderLine(_order.Description, total));
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return _order;
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}
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}
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