order total: TotalInCents on both Orders, mapped into OrderDto and OrderData

yak: ordertotalincents-on-both-sides-dto-mapping-j00p

src/After/DbContext.cs

@@ -29,6 +29,9 @@ public sealed class OrderData : DbBase
     /// <summary>Free-text description of what this order is for.</summary>
     public string Description { get; set; } = string.Empty;
 
+    /// <summary>Order total in cents of the stored order.</summary>
+    public int TotalInCents { get; set; }
+
     /// <summary>
     /// Foreign key to the owning client: <see cref="Guid.Empty"/> when the
     /// order has no client, or when its client had no id yet at save time —
@@ -101,6 +104,7 @@ public class DbContext
         {
             var row = (OrderData)existing;               // refresh, keep row identity
             row.Description = fresh.Description;
+            row.TotalInCents = fresh.TotalInCents;
             row.ClientId = fresh.ClientId;
             return;
         }

src/After/Mappers.cs

@@ -72,6 +72,7 @@ public static class Mappers
         {
             Id = order.Id,
             Description = order.Description,
+            TotalInCents = order.TotalInCents,
             ClientDto = order.Client is null ? null : MapClient(order.Client, seen),
         };
         seen[order] = dto;
@@ -102,6 +103,7 @@ public static class Mappers
         {
             Id = dto.Id,
             Description = dto.Description,
+            TotalInCents = dto.TotalInCents,
             Client = dto.ClientDto is null ? null : UnmapClient(dto.ClientDto, seen),
         };
         seen[dto] = order;
@@ -132,6 +134,7 @@ public static class Mappers
         {
             Id = order.Id,
             Description = order.Description,
+            TotalInCents = order.TotalInCents,
             ClientId = order.Client?.Id ?? Guid.Empty,
         };
     }

src/After/Order.cs

@@ -17,6 +17,13 @@ public class Order
     /// <summary>Free-text description of what this order is for.</summary>
     public string Description { get; set; } = string.Empty;
 
+    /// <summary>
+    /// Order total in cents (integer — no floating-point money). A normal
+    /// attribute: it is persisted in <see cref="OrderData"/> and mapped
+    /// one-on-one into <see cref="OrderDto.TotalInCents"/>.
+    /// </summary>
+    public int TotalInCents { get; set; }
+
     /// <summary>
     /// The client that owns this order. Set automatically by
     /// <see cref="ClientOrders"/> when the order is added to

src/After/OrderDto.cs

@@ -13,6 +13,9 @@ public sealed record OrderDto
     /// <summary>Free-text description of what this order is for.</summary>
     public string Description { get; init; } = string.Empty;
 
+    /// <summary>Order total in cents of the underlying order.</summary>
+    public int TotalInCents { get; init; }
+
     /// <summary>
     /// Back-reference to the owning client, or <c>null</c> for a bare order
     /// that has not been added to any client.

src/Before.Console/Program.cs

@@ -18,10 +18,10 @@ DbBase.Context = ctx;
 var jane = new Client { Name = "Jane Doe" };
 var bob  = new Client { Name = "Bob Smith" };
 
-jane.Orders.Add(new Order { Description = "Design consultation" });
+jane.Orders.Add(new Order { Description = "Design consultation", TotalInCents = 120_00 });
-jane.Orders.Add(new Order { Description = "Website redesign" });
+jane.Orders.Add(new Order { Description = "Website redesign", TotalInCents = 750_00 });
 
-bob.Orders.Add(new Order { Description = "Monthly retainer" });
+bob.Orders.Add(new Order { Description = "Monthly retainer", TotalInCents = 85_00 });
 
 // Orders need to be attached too so they get IDs:
 ctx.Attach(jane.Orders[0]);
@@ -38,7 +38,7 @@ foreach (var client in DbBase.Context!.Tracked.OfType<Client>())
 {
     Console.WriteLine($"{client.Name} [{client.Id}]");
     foreach (var order in client.Orders)
-        Console.WriteLine($"  - order [{order.Id}]: {order.Description}");
+        Console.WriteLine($"  - order [{order.Id}]: {order.Description} ({order.TotalInCents} cents)");
 }
 
 // ----- find by name -------------------------------------------------------

src/Before/Order.cs

@@ -11,6 +11,12 @@ public class Order : DbBase
     /// <summary>Free-text description of what this order is for.</summary>
     public string Description { get; set; } = string.Empty;
 
+    /// <summary>
+    /// Order total in cents (integer — no floating-point money). Part of the
+    /// persisted state, like every other scalar.
+    /// </summary>
+    public int TotalInCents { get; set; }
+
     /// <summary>
     /// The client that owns this order. Set automatically by
     /// <see cref="ClientOrders"/> when the order is added to

tests/BeforeAfter.Tests/AfterPersistenceTests.cs

@@ -16,7 +16,7 @@ public class AfterPersistenceTests
     {
         var db = new DbContext();
         var client = new Client { Name = "Acme" };
-        var order = new Order { Description = "one" };
+        var order = new Order { Description = "one", TotalInCents = 15000 };
         client.Orders.Add(order);
 
         db.Save(client);
@@ -29,6 +29,7 @@ public class AfterPersistenceTests
         var orderRow = Assert.Single(db.Orders);
         Assert.Equal(order.Id, orderRow.Id);
         Assert.Equal("one", orderRow.Description);
+        Assert.Equal(15000, orderRow.TotalInCents);
         Assert.Equal(client.Id, orderRow.ClientId);   // the graph is flattened to a key
     }
 
@@ -54,6 +55,7 @@ public class AfterPersistenceTests
         db.Save(order);
 
         order.Description = "one (edited)";
+        order.TotalInCents = 9900;
         client.Name = "Acme GmbH";
         db.Save(order);
         db.Save(client);
@@ -62,6 +64,7 @@ public class AfterPersistenceTests
         var orderRow = Assert.Single(db.Orders);
         Assert.Equal(order.Id, orderRow.Id);
         Assert.Equal("one (edited)", orderRow.Description);
+        Assert.Equal(9900, orderRow.TotalInCents);
         Assert.Equal(client.Id, orderRow.ClientId);
 
         var clientRow = Assert.Single(db.Clients);

tests/BeforeAfter.Tests/AfterTests.cs

@@ -54,12 +54,13 @@ public class AfterTests
     public void ToOrderDto_maps_all_scalar_fields()
     {
         var id = Guid.NewGuid();
-        var order = new Order { Id = id, Description = "one" };
+        var order = new Order { Id = id, Description = "one", TotalInCents = 15000 };
 
         var dto = Mappers.ToOrderDto(order);
 
         Assert.Equal(id, dto.Id);
         Assert.Equal("one", dto.Description);
+        Assert.Equal(15000, dto.TotalInCents);
     }
 
     [Fact]
@@ -78,12 +79,13 @@ public class AfterTests
     public void FromOrderDto_maps_all_scalar_fields()
     {
         var id = Guid.NewGuid();
-        var dto = new OrderDto { Id = id, Description = "one" };
+        var dto = new OrderDto { Id = id, Description = "one", TotalInCents = 15000 };
 
         var order = Mappers.FromOrderDto(dto);
 
         Assert.Equal(id, order.Id);
         Assert.Equal("one", order.Description);
+        Assert.Equal(15000, order.TotalInCents);
     }
 
     // ---------------------------------------------------------------------
@@ -129,7 +131,7 @@ public class AfterTests
     public void Domain_round_trip_preserves_all_state()
     {
         var client = new Client { Id = Guid.NewGuid(), Name = "Acme" };
-        var order = new Order { Id = Guid.NewGuid(), Description = "one" };
+        var order = new Order { Id = Guid.NewGuid(), Description = "one", TotalInCents = 15000 };
         client.Orders.Add(order);
 
         var roundTrip = Mappers.FromClientDto(Mappers.ToClientDto(client));
@@ -139,6 +141,7 @@ public class AfterTests
         var roundTripOrder = Assert.Single(roundTrip.Orders);
         Assert.Equal(order.Id, roundTripOrder.Id);
         Assert.Equal(order.Description, roundTripOrder.Description);
+        Assert.Equal(order.TotalInCents, roundTripOrder.TotalInCents);
         // The back-reference is still consistent on the reconstructed graph:
         Assert.Same(roundTrip, roundTripOrder.Client);
     }
@@ -159,6 +162,7 @@ public class AfterTests
         var roundTripOrder = Assert.Single(roundTrip.Orders);
         Assert.Equal(dtoOrder.Id, roundTripOrder.Id);
         Assert.Equal(dtoOrder.Description, roundTripOrder.Description);
+        Assert.Equal(dtoOrder.TotalInCents, roundTripOrder.TotalInCents);
         Assert.Same(roundTrip, roundTripOrder.ClientDto);
     }
 
@@ -244,7 +248,7 @@ public class AfterTests
     {
         var app = new WebApp();
         var client = new Client { Id = Guid.NewGuid(), Name = "Acme" };
-        var order = new Order { Id = Guid.NewGuid(), Description = "order one" };
+        var order = new Order { Id = Guid.NewGuid(), Description = "order one", TotalInCents = 15000 };
         client.Orders.Add(order);
 
         var view = app.ShowClient(Mappers.ToClientDto(client));