diff --git a/tests/CapySR.Tests/FlowTests.cs b/tests/CapySR.Tests/FlowTests.cs
index aa5c640..557db7a 100644
--- a/tests/CapySR.Tests/FlowTests.cs
+++ b/tests/CapySR.Tests/FlowTests.cs
@@ -13,7 +13,7 @@ namespace CapySR.Tests;
 // the whole pipeline through a real gateway: login, teams, overworld fights, a MOC floor
 public class FlowTests(ITestOutputHelper output)
 {
-    private static readonly GameWorld World = new(TestConfig(), NullLogger.Instance);
+    private static GameWorld World => TestWorld.Current;
 
     // the default harness plays real stages so an assertion about a fight is about the data,
     // not about whatever freesr-data.json happens to hold
@@ -66,7 +66,7 @@ public class FlowTests(ITestOutputHelper output)
         }
     }
 
-    private static bool HasData => new DataConfig().ResolvedSources.Any(Directory.Exists);
+    private static bool HasData => TestWorld.Available;
 
     [Fact]
     public async Task RosterAndTeamsLoad()
@@ -283,9 +283,14 @@ public class FlowTests(ITestOutputHelper output)
     [Fact]
     public async Task CalyxPlaysTheConfiguredBattle()
     {
+        if (!HasData)
+        {
+            return;
+        }
+
         var configured = World.Player.BattleConfig;
 
-        if (!HasData || configured.StageId == 0)
+        if (configured.StageId == 0)
         {
             output.WriteLine("no srtools battle_config; skipping");
             return;
@@ -489,6 +494,11 @@ public class FlowTests(ITestOutputHelper output)
             return;
         }
 
+        if (!HasData)
+        {
+            return;
+        }
+
         var floor = World.Data.Challenges.Values
             .Where(c => c.Kind == Data.Excel.ChallengeKind.MemoryOfChaos && c.NodeCount == 2)
             .OrderBy(c => c.ID)
diff --git a/tests/CapySR.Tests/GatewayIntegrationTests.cs b/tests/CapySR.Tests/GatewayIntegrationTests.cs
index 59494be..77cd9af 100644
--- a/tests/CapySR.Tests/GatewayIntegrationTests.cs
+++ b/tests/CapySR.Tests/GatewayIntegrationTests.cs
@@ -12,12 +12,16 @@ namespace CapySR.Tests;
 public class GatewayIntegrationTests
 {
     // one world for the whole class; loading the tables is the slow part
-    private static readonly GameWorld World =
-        new(new ServerConfig(), NullLogger.Instance);
+    private static GameWorld World => TestWorld.Current;
 
     [Fact]
     public async Task ClientCompletesHandshakeAndLogin()
     {
+        if (!TestWorld.Available)
+        {
+            return;
+        }
+
         var port = FreeUdpPort();
         // Persist off: a test must not read or write the machine's saved profile
         var config = new ServerConfig { GameServer = { Host = "127.0.0.1", Port = port, Nickname = "Capybara", Persist = false } };
@@ -54,6 +58,11 @@ public class GatewayIntegrationTests
     [Fact]
     public async Task UnmodelledRequestStillGetsAnswered()
     {
+        if (!TestWorld.Available)
+        {
+            return;
+        }
+
         var port = FreeUdpPort();
         var config = new ServerConfig { GameServer = { Host = "127.0.0.1", Port = port, Persist = false } };
         var handlers = HandlerRegistry.Build(NullLogger.Instance);
diff --git a/tests/CapySR.Tests/TestWorld.cs b/tests/CapySR.Tests/TestWorld.cs
new file mode 100644
index 0000000..08828a6
--- /dev/null
+++ b/tests/CapySR.Tests/TestWorld.cs
@@ -0,0 +1,18 @@
+using CapySR.Common;
+using CapySR.GameServer.Game;
+using Microsoft.Extensions.Logging.Abstractions;
+
+namespace CapySR.Tests;
+
+// The game data is a separate checkout, so a fresh clone has none. Tests that need it check
+// Available and return instead of failing. Building the world is deferred for the same
+// reason, and shared because loading the tables is the slow part of the suite.
+internal static class TestWorld
+{
+    private static readonly Lazy<GameWorld> Instance =
+        new(() => new GameWorld(new ServerConfig(), NullLogger.Instance));
+
+    public static bool Available { get; } = new DataConfig().ResolvedSources.Any(Directory.Exists);
+
+    public static GameWorld Current => Instance.Value;
+}