feat(inventory): TryDebitAsync dispatches currencies + Item

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

SVSim.UnitTests/Services/Inventory/InventoryDebitTests.cs

@@ -0,0 +1,76 @@
+using Microsoft.EntityFrameworkCore;
+using Microsoft.Extensions.DependencyInjection;
+using SVSim.Database;
+using SVSim.Database.Enums;
+using SVSim.Database.Models;
+using SVSim.Database.Services;
+using SVSim.Database.Services.Inventory;
+using SVSim.UnitTests.Infrastructure;
+
+namespace SVSim.UnitTests.Services.Inventory;
+
+public class InventoryDebitTests
+{
+    [Test]
+    public async Task Debit_Crystal_delegates_to_TrySpend()
+    {
+        using var factory = new SVSimTestFactory();
+        long viewerId = await factory.SeedViewerAsync();
+        using var scope = factory.Services.CreateScope();
+        var ctx = scope.ServiceProvider.GetRequiredService<SVSimDbContext>();
+        var v = await ctx.Viewers.FirstAsync(x => x.Id == viewerId);
+        v.Currency.Crystals = 500;
+        await ctx.SaveChangesAsync();
+
+        var inv = scope.ServiceProvider.GetRequiredService<IInventoryService>();
+        await using var tx = await inv.BeginAsync(viewerId);
+        var r = await tx.TryDebitAsync(UserGoodsType.Crystal, 0, 200);
+
+        Assert.That(r.Success, Is.True);
+        Assert.That(r.PostStateTotal, Is.EqualTo(300));
+    }
+
+    [Test]
+    public async Task Debit_Item_decrements_count_and_returns_post_state()
+    {
+        using var factory = new SVSimTestFactory();
+        long viewerId = await factory.SeedViewerAsync();
+        using var scope = factory.Services.CreateScope();
+        var ctx = scope.ServiceProvider.GetRequiredService<SVSimDbContext>();
+        const int itemId = 32000;
+        var item = new ItemEntry { Id = itemId };
+        ctx.Items.Add(item);
+        var v = await ctx.Viewers.Include(x => x.Items).ThenInclude(i => i.Item).FirstAsync(x => x.Id == viewerId);
+        v.Items.Add(new OwnedItemEntry { Item = item, Count = 10, Viewer = v });
+        await ctx.SaveChangesAsync();
+
+        var inv = scope.ServiceProvider.GetRequiredService<IInventoryService>();
+        await using var tx = await inv.BeginAsync(viewerId);
+        var r = await tx.TryDebitAsync(UserGoodsType.Item, itemId, 3);
+
+        Assert.That(r.Success, Is.True);
+        Assert.That(r.PostStateTotal, Is.EqualTo(7));
+    }
+
+    [Test]
+    public async Task Debit_Item_insufficient_returns_current_count_and_does_not_decrement()
+    {
+        using var factory = new SVSimTestFactory();
+        long viewerId = await factory.SeedViewerAsync();
+        using var scope = factory.Services.CreateScope();
+        var ctx = scope.ServiceProvider.GetRequiredService<SVSimDbContext>();
+        const int itemId = 32001;
+        var item = new ItemEntry { Id = itemId };
+        ctx.Items.Add(item);
+        var v = await ctx.Viewers.Include(x => x.Items).ThenInclude(i => i.Item).FirstAsync(x => x.Id == viewerId);
+        v.Items.Add(new OwnedItemEntry { Item = item, Count = 2, Viewer = v });
+        await ctx.SaveChangesAsync();
+
+        var inv = scope.ServiceProvider.GetRequiredService<IInventoryService>();
+        await using var tx = await inv.BeginAsync(viewerId);
+        var r = await tx.TryDebitAsync(UserGoodsType.Item, itemId, 5);
+
+        Assert.That(r.Outcome, Is.EqualTo(SpendOutcome.Insufficient));
+        Assert.That(r.PostStateTotal, Is.EqualTo(2));
+    }
+}