Practice battles work

SVSim.Bootstrap/Importers/GlobalsImporter.cs

@@ -28,6 +28,7 @@ public class GlobalsImporter
         JsonElement? mypageIndex = LoadCapture(capturesDir, "mypage-index");
         JsonElement? deckInfo = LoadCapture(capturesDir, "deck-info");
         JsonElement? paymentItemList = LoadCapture(capturesDir, "payment-item-list");
+        JsonElement? practiceInfo = LoadCapture(capturesDir, "practice-info");
 
         int total = 0;
 
@@ -69,6 +70,11 @@ public class GlobalsImporter
             total += await ImportPaymentItems(context, paymentItemList.Value);
         }
 
+        if (practiceInfo.HasValue)
+        {
+            total += await ImportPracticeOpponents(context, practiceInfo.Value);
+        }
+
         await context.SaveChangesAsync();
         Console.WriteLine($"[GlobalsImporter] Done: {total} total rows changed.");
         return total;
@@ -694,6 +700,47 @@ public class GlobalsImporter
     private static decimal ParseDecimal(string s) =>
         decimal.TryParse(s, System.Globalization.NumberStyles.Number, System.Globalization.CultureInfo.InvariantCulture, out var d) ? d : 0m;
 
+    // ---------- Practice Opponents ----------
+
+    /// <summary>
+    /// Capture is the full /practice/info envelope; <c>data</c> is a JSON ARRAY (not an object,
+    /// unlike most endpoints). Each row is one AI opponent row keyed on practice_id. Prod sends
+    /// numeric fields as strings — GetInt tolerates both. Rows present in the DB but missing
+    /// from the capture are LEFT INTACT (consistent with the rest of GlobalsImporter; partial
+    /// captures shouldn't silently delete entries).
+    /// </summary>
+    private async Task<int> ImportPracticeOpponents(SVSimDbContext context, JsonElement practiceData)
+    {
+        if (practiceData.ValueKind != JsonValueKind.Array) return 0;
+
+        var existing = await context.PracticeOpponents.ToDictionaryAsync(e => e.Id);
+        int created = 0, updated = 0;
+
+        foreach (var row in practiceData.EnumerateArray())
+        {
+            int practiceId = GetInt(row, "practice_id");
+            if (practiceId == 0) continue; // malformed row
+
+            var entry = existing.TryGetValue(practiceId, out var ex) ? ex : new PracticeOpponentEntry { Id = practiceId };
+            entry.TextId = GetString(row, "text_id");
+            entry.ClassId = GetInt(row, "class_id");
+            entry.CharaId = GetInt(row, "chara_id");
+            entry.DegreeId = GetInt(row, "degree_id");
+            entry.AiDeckLevel = GetInt(row, "ai_deck_level");
+            entry.AiLogicLevel = GetInt(row, "ai_logic_level");
+            entry.AiMaxLife = GetInt(row, "ai_max_life");
+            entry.Battle3dFieldId = GetString(row, "battle3dfield_id", "1");
+            entry.IsMaintenance = GetBool(row, "is_maintenance");
+            entry.IsCampaignPractice = GetBool(row, "is_campaign_practice");
+
+            if (ex is null) { context.PracticeOpponents.Add(entry); created++; }
+            else updated++;
+        }
+
+        Console.WriteLine($"[GlobalsImporter] PracticeOpponents: +{created}/~{updated}");
+        return created + updated;
+    }
+
     // ---------- Helpers ----------
 
     private static void WarnOrphans(string label, int count)

SVSim.Database/Migrations/20260524022437_PracticeOpponents.cs

@@ -0,0 +1,46 @@
+using System;
+using Microsoft.EntityFrameworkCore.Migrations;
+
+#nullable disable
+
+namespace SVSim.Database.Migrations
+{
+    /// <inheritdoc />
+    public partial class PracticeOpponents : Migration
+    {
+        /// <inheritdoc />
+        protected override void Up(MigrationBuilder migrationBuilder)
+        {
+            migrationBuilder.CreateTable(
+                name: "PracticeOpponents",
+                columns: table => new
+                {
+                    Id = table.Column<int>(type: "integer", nullable: false),
+                    PracticeId = table.Column<int>(type: "integer", nullable: false),
+                    TextId = table.Column<string>(type: "text", nullable: false),
+                    ClassId = table.Column<int>(type: "integer", nullable: false),
+                    CharaId = table.Column<int>(type: "integer", nullable: false),
+                    DegreeId = table.Column<int>(type: "integer", nullable: false),
+                    AiDeckLevel = table.Column<int>(type: "integer", nullable: false),
+                    AiLogicLevel = table.Column<int>(type: "integer", nullable: false),
+                    AiMaxLife = table.Column<int>(type: "integer", nullable: false),
+                    Battle3dFieldId = table.Column<string>(type: "text", nullable: false),
+                    IsMaintenance = table.Column<bool>(type: "boolean", nullable: false),
+                    IsCampaignPractice = table.Column<bool>(type: "boolean", nullable: false),
+                    DateCreated = table.Column<DateTime>(type: "timestamp with time zone", nullable: false),
+                    DateUpdated = table.Column<DateTime>(type: "timestamp with time zone", nullable: true)
+                },
+                constraints: table =>
+                {
+                    table.PrimaryKey("PK_PracticeOpponents", x => x.Id);
+                });
+        }
+
+        /// <inheritdoc />
+        protected override void Down(MigrationBuilder migrationBuilder)
+        {
+            migrationBuilder.DropTable(
+                name: "PracticeOpponents");
+        }
+    }
+}

SVSim.Database/Migrations/SVSimDbContextModelSnapshot.cs

@@ -25486,6 +25486,57 @@ namespace SVSim.Database.Migrations
                     b.ToTable("PaymentItems");
                 });
 
+            modelBuilder.Entity("SVSim.Database.Models.PracticeOpponentEntry", b =>
+                {
+                    b.Property<int>("Id")
+                        .HasColumnType("integer");
+
+                    b.Property<int>("AiDeckLevel")
+                        .HasColumnType("integer");
+
+                    b.Property<int>("AiLogicLevel")
+                        .HasColumnType("integer");
+
+                    b.Property<int>("AiMaxLife")
+                        .HasColumnType("integer");
+
+                    b.Property<string>("Battle3dFieldId")
+                        .IsRequired()
+                        .HasColumnType("text");
+
+                    b.Property<int>("CharaId")
+                        .HasColumnType("integer");
+
+                    b.Property<int>("ClassId")
+                        .HasColumnType("integer");
+
+                    b.Property<DateTime>("DateCreated")
+                        .HasColumnType("timestamp with time zone");
+
+                    b.Property<DateTime?>("DateUpdated")
+                        .HasColumnType("timestamp with time zone");
+
+                    b.Property<int>("DegreeId")
+                        .HasColumnType("integer");
+
+                    b.Property<bool>("IsCampaignPractice")
+                        .HasColumnType("boolean");
+
+                    b.Property<bool>("IsMaintenance")
+                        .HasColumnType("boolean");
+
+                    b.Property<int>("PracticeId")
+                        .HasColumnType("integer");
+
+                    b.Property<string>("TextId")
+                        .IsRequired()
+                        .HasColumnType("text");
+
+                    b.HasKey("Id");
+
+                    b.ToTable("PracticeOpponents");
+                });
+
             modelBuilder.Entity("SVSim.Database.Models.PreReleaseInfo", b =>
                 {
                     b.Property<int>("Id")

SVSim.Database/Models/PracticeOpponentEntry.cs

@@ -0,0 +1,49 @@
+using SVSim.Database.Common;
+
+namespace SVSim.Database.Models;
+
+/// <summary>
+/// One row per AI opponent shown on the practice (solo-play) opponent select screen.
+/// Populated from prod /practice/info captures by SVSim.Bootstrap.GlobalsImporter.
+///
+/// The (<see cref="ClassId"/>, <see cref="AiDeckLevel"/>) pair MUST exist in the client's
+/// baked-in master CSV `ai/practice_ai_setting`; if it doesn't, the client's
+/// PracticeAISettingDataSet.GetSettingData throws InvalidOperationException and the
+/// difficulty-select dialog crashes BEFORE /practice/start is sent. Prod's catalog is
+/// the safe source of truth — we can't see the CSV directly.
+/// </summary>
+public class PracticeOpponentEntry : BaseEntity<int>
+{
+    /// <summary>Practice slot id (Id = practice_id from the wire; also unique).</summary>
+    public int PracticeId { get => Id; set => Id = value; }
+
+    /// <summary>Text-table key resolved client-side via Data.Master.GetPracticeText.</summary>
+    public string TextId { get; set; } = string.Empty;
+
+    /// <summary>Class (leader) id the AI plays.</summary>
+    public int ClassId { get; set; }
+
+    /// <summary>Portrait / character id (leader art).</summary>
+    public int CharaId { get; set; }
+
+    /// <summary>Title-degree id shown next to the AI name. -1 when unset.</summary>
+    public int DegreeId { get; set; }
+
+    /// <summary>AI deck-strength tier; key into the client's practice_ai_setting CSV.</summary>
+    public int AiDeckLevel { get; set; }
+
+    /// <summary>AI decision-making tier.</summary>
+    public int AiLogicLevel { get; set; }
+
+    /// <summary>Starting HP for the AI side (typically 20; 10 for the easiest "tutorial" rows).</summary>
+    public int AiMaxLife { get; set; }
+
+    /// <summary>3D battlefield asset id (string on the wire; client int.TryParse's it).</summary>
+    public string Battle3dFieldId { get; set; } = "1";
+
+    /// <summary>true => entry shown but disabled with a maintenance suffix.</summary>
+    public bool IsMaintenance { get; set; }
+
+    /// <summary>true => entry is a special event-tied "campaign" practice.</summary>
+    public bool IsCampaignPractice { get; set; }
+}

SVSim.Database/Repositories/Globals/GlobalsRepository.cs

@@ -111,4 +111,7 @@ public class GlobalsRepository : IGlobalsRepository
 
     public Task<List<ShadowverseCardSetEntry>> GetRotationCardSets() =>
         _dbContext.CardSets.AsNoTracking().Where(s => s.IsInRotation).ToListAsync();
+
+    public Task<List<PracticeOpponentEntry>> GetPracticeOpponents() =>
+        _dbContext.PracticeOpponents.AsNoTracking().OrderBy(e => e.ClassId).ThenBy(e => e.Id).ToListAsync();
 }

SVSim.Database/Repositories/Globals/IGlobalsRepository.cs

@@ -32,4 +32,5 @@ public interface IGlobalsRepository
     Task<List<FeatureMaintenanceEntry>> GetFeatureMaintenances();
     Task<PreReleaseInfo?> GetPreReleaseInfo();
     Task<List<ShadowverseCardSetEntry>> GetRotationCardSets();
+    Task<List<PracticeOpponentEntry>> GetPracticeOpponents();
 }

SVSim.Database/SVSimDbContext.cs

@@ -59,6 +59,7 @@ public class SVSimDbContext : DbContext
     public DbSet<MaintenanceCardEntry> MaintenanceCards => Set<MaintenanceCardEntry>();
     public DbSet<FeatureMaintenanceEntry> FeatureMaintenances => Set<FeatureMaintenanceEntry>();
     public DbSet<PreReleaseInfo> PreReleaseInfos => Set<PreReleaseInfo>();
+    public DbSet<PracticeOpponentEntry> PracticeOpponents => Set<PracticeOpponentEntry>();
 
     #endregion
 

SVSim.EmulatedEntrypoint/Controllers/DeckController.cs

@@ -256,13 +256,6 @@ public class DeckController : SVSimController
         return Task.FromResult<ActionResult<EmptyResponse>>(new EmptyResponse());
     }
 
-    private bool TryGetViewerId(out long viewerId)
-    {
-        viewerId = 0;
-        var claim = User.Claims.FirstOrDefault(c => c.Type == ShadowverseClaimTypes.ViewerIdClaim)?.Value;
-        return claim is not null && long.TryParse(claim, out viewerId);
-    }
-
     /// <summary>
     /// Convert a flat `card_id_array` (cards repeated for count) into a grouped DeckCard list.
     /// Cards not in the DB are silently dropped — until CardImport lands the result is always

SVSim.EmulatedEntrypoint/Controllers/PracticeController.cs

@@ -1,9 +1,8 @@
 using Microsoft.AspNetCore.Mvc;
 using SVSim.Database.Enums;
-using SVSim.Database.Models;
-using SVSim.Database.Repositories.Viewer;
-using SVSim.EmulatedEntrypoint.Constants;
 using SVSim.EmulatedEntrypoint.Models.Dtos;
+using SVSim.Database.Repositories.Deck;
+using SVSim.Database.Repositories.Globals;
 using SVSim.EmulatedEntrypoint.Models.Dtos.Requests;
 using SVSim.EmulatedEntrypoint.Models.Dtos.Requests.Common;
 using SVSim.EmulatedEntrypoint.Models.Dtos.Requests.Practice;
@@ -13,94 +12,59 @@ namespace SVSim.EmulatedEntrypoint.Controllers;
 
 public class PracticeController : SVSimController
 {
-    // Hand-curated AI opponents (audit B14 pattern). Replace with master data when the
+    private readonly IDeckRepository _deckRepository;
-    // practice subsystem is built out.
+    private readonly IGlobalsRepository _globalsRepository;
-    private static readonly List<PracticeOpponent> StubOpponents = new()
-    {
-        new PracticeOpponent
-        {
-            PracticeId = 1,
-            TextId = "Practice_001",
-            ClassId = 1,
-            CharaId = 1,
-            DegreeId = 0,
-            AiDeckLevel = 1,
-            AiLogicLevel = 1,
-            AiMaxLife = 20,
-            Battle3dFieldId = "1",
-            IsCampaignPractice = false
-        },
-        new PracticeOpponent
-        {
-            PracticeId = 2,
-            TextId = "Practice_002",
-            ClassId = 2,
-            CharaId = 2,
-            DegreeId = 0,
-            AiDeckLevel = 2,
-            AiLogicLevel = 2,
-            AiMaxLife = 20,
-            Battle3dFieldId = "1",
-            IsCampaignPractice = false
-        },
-        new PracticeOpponent
-        {
-            PracticeId = 3,
-            TextId = "Practice_003",
-            ClassId = 3,
-            CharaId = 3,
-            DegreeId = 0,
-            AiDeckLevel = 3,
-            AiLogicLevel = 3,
-            AiMaxLife = 25,
-            Battle3dFieldId = "1",
-            IsCampaignPractice = false
-        }
-    };
 
-    private readonly IViewerRepository _viewerRepository;
+    public PracticeController(IDeckRepository deckRepository, IGlobalsRepository globalsRepository)
-
-    public PracticeController(IViewerRepository viewerRepository)
     {
-        _viewerRepository = viewerRepository;
+        _deckRepository = deckRepository;
+        _globalsRepository = globalsRepository;
     }
 
     /// <summary>
     /// /practice/info — returns the AI opponent catalog. Response data is a JSON array
-    /// directly (not wrapped in an object), per spec.
+    /// directly (not wrapped in an object), per spec. Backed by PracticeOpponents table,
+    /// seeded by SVSim.Bootstrap from prod-captures/practice-info-*.json.
     /// </summary>
     [HttpPost("info")]
-    public Task<List<PracticeOpponent>> Info(BaseRequest request)
+    public async Task<List<PracticeOpponent>> Info(BaseRequest request)
     {
-        return Task.FromResult(StubOpponents);
+        var rows = await _globalsRepository.GetPracticeOpponents();
+        return rows.Select(e => new PracticeOpponent
+        {
+            PracticeId = e.PracticeId,
+            TextId = e.TextId,
+            ClassId = e.ClassId,
+            CharaId = e.CharaId,
+            DegreeId = e.DegreeId,
+            AiDeckLevel = e.AiDeckLevel,
+            AiLogicLevel = e.AiLogicLevel,
+            AiMaxLife = e.AiMaxLife,
+            Battle3dFieldId = e.Battle3dFieldId,
+            IsMaintenance = e.IsMaintenance,
+            IsCampaignPractice = e.IsCampaignPractice,
+        }).ToList();
     }
 
     /// <summary>
     /// /practice/deck_list — returns viewer's decks scoped by format (always Format.All
-    /// per spec, server can ignore the request field).
+    /// per spec, server can ignore the request field). Fetched via IDeckRepository so the
+    /// DeckCard.Card navigation is Included; going through the heavier viewer-graph query
+    /// drops that ThenInclude and ships 40 zeros instead of real card ids, which then
+    /// NREs the client's SBattleLoad.InitPlayer (CardCreator returns null on id=0).
     /// </summary>
     [HttpPost("deck_list")]
     public async Task<ActionResult<PracticeDeckListResponse>> DeckList(DeckFormatRequest request)
     {
-        var shortUdidClaim = User.Claims.FirstOrDefault(c => c.Type == ShadowverseClaimTypes.ShortUdidClaim)?.Value;
+        if (!TryGetViewerId(out long viewerId)) return Unauthorized();
-        if (shortUdidClaim is null || !long.TryParse(shortUdidClaim, out long shortUdid))
-        {
-            return Unauthorized();
-        }
 
-        Viewer? viewer = await _viewerRepository.GetViewerByShortUdid(shortUdid);
+        var byFormat = await _deckRepository.GetDecksByFormats(viewerId, new[] { Format.Rotation, Format.Unlimited });
-        if (viewer is null)
-        {
-            return NotFound();
-        }
 
         return new PracticeDeckListResponse
         {
             MaintenanceCardList = new List<long>(),
-            UserDeckRotation = viewer.Decks.Where(d => d.Format == Format.Rotation)
+            UserDeckRotation = byFormat[Format.Rotation].Select(d => new UserDeck(d)).ToList(),
-                .Select(d => new UserDeck(d)).ToList(),
+            UserDeckUnlimited = byFormat[Format.Unlimited].Select(d => new UserDeck(d)).ToList(),
-            UserDeckUnlimited = viewer.Decks.Where(d => d.Format == Format.Unlimited)
-                .Select(d => new UserDeck(d)).ToList()
         };
     }
 

SVSim.EmulatedEntrypoint/Controllers/SVSimController.cs

@@ -1,6 +1,7 @@
 using Microsoft.AspNetCore.Authorization;
 using Microsoft.AspNetCore.Http;
 using Microsoft.AspNetCore.Mvc;
+using SVSim.EmulatedEntrypoint.Constants;
 using SVSim.EmulatedEntrypoint.Security;
 using SVSim.EmulatedEntrypoint.Security.SteamSessionAuthentication;
 
@@ -14,5 +15,16 @@ namespace SVSim.EmulatedEntrypoint.Controllers
     [Authorize(AuthenticationSchemes = SteamAuthenticationConstants.SchemeName)]
     public abstract class SVSimController : ControllerBase
     {
+        /// <summary>
+        /// Reads the authenticated viewer's internal id from the ViewerId claim populated by
+        /// <c>SteamSessionAuthenticationHandler</c>. Returns false (and viewerId = 0) when the
+        /// claim is missing or unparseable — handler should respond with Unauthorized().
+        /// </summary>
+        protected bool TryGetViewerId(out long viewerId)
+        {
+            viewerId = 0;
+            var claim = User.Claims.FirstOrDefault(c => c.Type == ShadowverseClaimTypes.ViewerIdClaim)?.Value;
+            return claim is not null && long.TryParse(claim, out viewerId);
+        }
     }
 }

SVSim.EmulatedEntrypoint/Models/Dtos/Responses/Practice/PracticeOpponent.cs

@@ -45,9 +45,9 @@ public class PracticeOpponent
     [JsonPropertyName("battle3dfield_id")]
     [Key("battle3dfield_id")] public string Battle3dFieldId { get; set; } = "1";
 
-    /// <summary>Optional. true => entry disabled, client prepends maintenance suffix.</summary>
+    /// <summary>true => entry disabled, client prepends maintenance suffix. Must always be emitted: client reads with `data["is_maintenance"] != null` but LitJson throws KeyNotFoundException on a missing key.</summary>
     [JsonPropertyName("is_maintenance")]
-    [Key("is_maintenance")] public bool? IsMaintenance { get; set; }
+    [Key("is_maintenance")] public bool IsMaintenance { get; set; }
 
     /// <summary>true => entry is a special "campaign" practice (event-tied).</summary>
     [JsonPropertyName("is_campaign_practice")]

SVSim.EmulatedEntrypoint/Models/Dtos/Responses/Practice/PracticeStartResponse.cs

@@ -7,10 +7,11 @@ namespace SVSim.EmulatedEntrypoint.Models.Dtos.Responses.Practice;
 public class PracticeStartResponse
 {
     /// <summary>
-    /// Optional mission/achievement evaluation snapshot. Spec: safe to omit entirely;
+    /// Mission/achievement evaluation snapshot. Client reads it via
-    /// client tolerates absence (defensive `Keys.Contains` check). Always null in our
+    /// `data.Keys.Contains("mission_parameter")` so omitting the key is technically
-    /// minimal impl 窶・we don't model missions.
+    /// safe — but prod always emits `mission_parameter: []` and matching prod exactly
+    /// avoids surprises if any other code path drops the defensive check.
     /// </summary>
     [JsonPropertyName("mission_parameter")]
-    [Key("mission_parameter")] public object? MissionParameter { get; set; }
+    [Key("mission_parameter")] public List<object> MissionParameter { get; set; } = new();
 }

SVSim.UnitTests/Controllers/PracticeControllerTests.cs

@@ -1,7 +1,12 @@
 using System.Net;
 using System.Text;
 using System.Text.Json;
+using Microsoft.EntityFrameworkCore;
+using Microsoft.Extensions.DependencyInjection;
+using SVSim.Database;
 using SVSim.Database.Enums;
+using SVSim.Database.Models;
+using SVSim.Database.Repositories.Deck;
 using SVSim.EmulatedEntrypoint.Extensions;
 using SVSim.UnitTests.Infrastructure;
 
@@ -25,6 +30,9 @@ public class PracticeControllerTests
     public async Task Info_returns_non_empty_opponent_array()
     {
         using var factory = new SVSimTestFactory();
+        // Practice opponents are bootstrapped from prod-captures/practice-info-*.json into the
+        // PracticeOpponents table — empty by default in tests, so seed first.
+        await factory.SeedGlobalsAsync();
         long viewerId = await factory.SeedViewerAsync();
         using var client = factory.CreateAuthenticatedClient(viewerId);
 
@@ -41,6 +49,26 @@ public class PracticeControllerTests
         Assert.That(doc.RootElement[0].GetProperty("practice_id").GetInt32(), Is.GreaterThan(0));
     }
 
+    [Test]
+    public async Task Info_returns_empty_array_when_db_not_bootstrapped()
+    {
+        using var factory = new SVSimTestFactory();
+        // Skip SeedGlobalsAsync — table is empty. /practice/info must still 200, not 500: the
+        // client treats an empty array as "no opponents" and the practice menu just shows nothing.
+        long viewerId = await factory.SeedViewerAsync();
+        using var client = factory.CreateAuthenticatedClient(viewerId);
+
+        var response = await client.PostAsync("/practice/info",
+            new StringContent(BaseRequestJson, Encoding.UTF8, "application/json"));
+
+        var body = await response.Content.ReadAsStringAsync();
+        Assert.That(response.StatusCode, Is.EqualTo(HttpStatusCode.OK), body);
+
+        using var doc = JsonDocument.Parse(body);
+        Assert.That(doc.RootElement.ValueKind, Is.EqualTo(JsonValueKind.Array));
+        Assert.That(doc.RootElement.GetArrayLength(), Is.EqualTo(0));
+    }
+
     [Test]
     public async Task DeckList_returns_viewer_decks()
     {
@@ -65,6 +93,51 @@ public class PracticeControllerTests
         Assert.That(unlimited[0].GetProperty("deck_name").GetString(), Is.EqualTo("Unlimited Deck"));
     }
 
+    [Test]
+    public async Task DeckList_card_id_array_contains_real_card_ids()
+    {
+        // Regression for the deck-include bug: PracticeController used to load the viewer
+        // via GetViewerByShortUdid, which Includes Decks but NOT Decks.Cards.Card. The
+        // DeckCard.Card navigation defaults to `new ShadowverseCardEntry()` (Id=0), so the
+        // wire response shipped 40 zeros — which then NREs the client's SBattleLoad
+        // (CardCreator returns null for id=0 → BattlePlayerBase.AddToDeck(null)). Asserts
+        // a real card id round-trips end-to-end so the same .Include drop can't reappear.
+        using var factory = new SVSimTestFactory();
+        long viewerId = await factory.SeedViewerAsync();
+
+        const long CardId = 900_123_456L;
+        using (var scope = factory.Services.CreateScope())
+        {
+            var db = scope.ServiceProvider.GetRequiredService<SVSimDbContext>();
+            db.Cards.Add(new ShadowverseCardEntry { Id = CardId, Name = "Regression Card" });
+            await db.SaveChangesAsync();
+        }
+        await factory.SeedDeckAsync(viewerId, Format.Rotation, number: 1);
+        using (var scope = factory.Services.CreateScope())
+        {
+            var db = scope.ServiceProvider.GetRequiredService<SVSimDbContext>();
+            var repo = scope.ServiceProvider.GetRequiredService<IDeckRepository>();
+            var card = await db.Cards.FirstAsync(c => c.Id == CardId);
+            await repo.UpsertDeck(viewerId, Format.Rotation, 1,
+                d => d.Cards = new List<DeckCard> { new() { Card = card, Count = 3 } });
+        }
+
+        using var client = factory.CreateAuthenticatedClient(viewerId);
+        var response = await client.PostAsync("/practice/deck_list",
+            new StringContent(DeckFormatRequestJson(Format.All), Encoding.UTF8, "application/json"));
+
+        var body = await response.Content.ReadAsStringAsync();
+        Assert.That(response.StatusCode, Is.EqualTo(HttpStatusCode.OK), body);
+
+        using var doc = JsonDocument.Parse(body);
+        var cards = doc.RootElement.GetProperty("user_deck_rotation")[0].GetProperty("card_id_array");
+        Assert.That(cards.GetArrayLength(), Is.EqualTo(3), "DeckCard.Count should expand into Count copies in card_id_array");
+        for (int i = 0; i < 3; i++)
+        {
+            Assert.That(cards[i].GetInt64(), Is.EqualTo(CardId), "card_id must round-trip — Includes are dropping DeckCard.Card");
+        }
+    }
+
     [Test]
     public async Task DeckList_empty_when_viewer_has_none()
     {