diff --git a/manifest.json b/manifest.json
index e830533..1096ae3 100644
--- a/manifest.json
+++ b/manifest.json
@@ -3,7 +3,17 @@
   "name": "Test Defaults and Patches",
   "version": "1.0.0",
   "author": "ct",
-  "description": "Test mod demonstrating property patches system with wildcard and targeted patches",
+  "description": "Test fixture of the property patches system: a targeted patch (Marao, food/ration) and wildcard patches of every character and item. Marked as a fixture, so --all-mods and games never load it; the property_patches itest loads it explicitly (--with-mods=test_defaults_and_patches --itest=property_patches) and checks the merged entities.",
   "category": "other",
-  "depends": ["visual_novel_core>=1"]
+  "depends": [
+    "visual_novel_core>=1",
+    "murakami>=1",
+    "cooking>=1",
+    "characters_base>=1",
+    "items_base>=1"
+  ],
+  "fixture": true,
+  "sources": [
+    "src/*.cs"
+  ]
 }
diff --git a/src/PropertyPatchesTest.cs b/src/PropertyPatchesTest.cs
new file mode 100644
index 0000000..011bd14
--- /dev/null
+++ b/src/PropertyPatchesTest.cs
@@ -0,0 +1,152 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text.Json;
+using Cthangover.Core.Bootstrap;
+using Cthangover.Core.Characters;
+using Cthangover.Core.Items;
+using Cthangover.Core.Mods;
+using Cthangover.Core.Mods.Resolvers;
+using Cthangover.Core.Utils;
+using Godot;
+
+namespace Mods.TestDefaultsAndPatches
+{
+    /// <summary>
+    /// Entry point of the property patches itest: active only with
+    /// <c>--itest=property_patches</c>. The fixture itself is loaded only by
+    /// <c>--with-mods=test_defaults_and_patches</c> (manifest <c>fixture</c>).
+    /// </summary>
+    public class PropertyPatchesTestInitializer : IModInitializer
+    {
+        private static bool queued;
+
+        public void OnModLoaded(string modId) { }
+
+        public void OnModResourcesReady()
+        {
+            if (queued || !OS.GetCmdlineUserArgs().Contains("--itest=property_patches"))
+                return;
+            queued = true;
+            GameLogger.Log("TEST", "PropertyPatchesTest: activating");
+            (Godot.Engine.GetMainLoop() as SceneTree)?.Root?.CallDeferred("add_child", new PropertyPatchesTestDriverNode());
+        }
+    }
+
+    /// <summary>
+    /// Checks the merge of <c>patches/character.json</c> and
+    /// <c>patches/item.json</c> into the real entities of other mods, as the
+    /// game resolves them: a targeted patch wins over the wildcard, the
+    /// wildcard reaches every entity of the kind, and untouched typed fields
+    /// survive. Prints <c>[TEST_RESULT] name=property_patches</c> and quits.
+    /// </summary>
+    public partial class PropertyPatchesTestDriverNode : Node
+    {
+        private const string ResultName = "property_patches";
+        private const double TimeoutSeconds = 60;
+
+        private int passed;
+        private int failed;
+        private double elapsed;
+        private bool done;
+
+        public override void _Process(double delta)
+        {
+            if (done)
+                return;
+            elapsed += delta;
+            if (elapsed > TimeoutSeconds)
+            {
+                Check("boot finished in time", false);
+                Finish();
+                return;
+            }
+
+            if (!Boot.IsReady)
+                return;
+
+            try
+            {
+                Run();
+            }
+            catch (Exception ex)
+            {
+                Check($"no exception ({ex.GetType().Name}: {ex.Message})", false);
+            }
+
+            Finish();
+        }
+
+        private void Run()
+        {
+            var characterPatches = Patches.Collect("character");
+            Check("character patches collected (Marao + *)", characterPatches != null && characterPatches.ContainsKey("Marao") && characterPatches.ContainsKey("*"));
+            var itemPatches = Patches.Collect("item");
+            Check("item patches collected (food/ration + *)", itemPatches != null && itemPatches.ContainsKey("food/ration") && itemPatches.ContainsKey("*"));
+
+            var characters = Entities.Collect<CharacterInfo>();
+            Check("Marao resolved", characters.ContainsKey("Marao"));
+            if (characters.TryGetValue("Marao", out var marao))
+            {
+                Expect(marao.ExtraProperties, "TestPatched", "42", "Marao: targeted value");
+                Expect(marao.ExtraProperties, "TestDefault", "100", "Marao: targeted beats wildcard");
+                Expect(marao.ExtraProperties, "TestGlobalPatch", "1", "Marao: wildcard-only key");
+            }
+
+            var other = characters.Values.FirstOrDefault(c => c.ID != "Marao");
+            Check("another character exists", other != null);
+            if (other != null)
+            {
+                Expect(other.ExtraProperties, "TestDefault", "-20", $"{other.ID}: wildcard value");
+                Check($"{other.ID}: no targeted key", other.ExtraProperties == null || !other.ExtraProperties.ContainsKey("TestPatched"));
+            }
+
+            var items = Entities.Collect<ItemInfo>();
+            if (items.TryGetValue("food/ration", out var ration))
+            {
+                Expect(ration.ExtraProperties, "Durability", "99", "ration: targeted beats wildcard");
+                Expect(ration.ExtraProperties, "SpecialProp", "true", "ration: targeted-only key");
+                Expect(ration.ExtraProperties, "GlobalItemProp", "patched", "ration: wildcard-only key");
+                Check("ration: typed field survives the merge", !string.IsNullOrEmpty(ration.Name));
+            }
+            else
+                Check("food/ration resolved", false);
+
+            if (items.TryGetValue("food/wolf_meat", out var meat))
+                Expect(meat.ExtraProperties, "Durability", "50", "wolf_meat: wildcard value");
+            else
+                Check("food/wolf_meat resolved", false);
+        }
+
+        private void Expect(Dictionary<string, object> properties, string key, string expected, string what)
+        {
+            var actual = properties != null && properties.TryGetValue(key, out var value) ? Text(value) : null;
+            Check($"{what}: {key}={expected}" + (actual == expected ? string.Empty : $" (got {actual ?? "nothing"})"), actual == expected);
+        }
+
+        private static string Text(object value) => value switch
+        {
+            JsonElement { ValueKind: JsonValueKind.String } s => s.GetString(),
+            JsonElement e => e.GetRawText(),
+            bool b => b ? "true" : "false",
+            null => null,
+            _ => Convert.ToString(value, System.Globalization.CultureInfo.InvariantCulture),
+        };
+
+        private void Check(string what, bool ok)
+        {
+            if (ok)
+                passed++;
+            else
+                failed++;
+            GameLogger.Log("TEST", $"  [{(ok ? "PASS" : "FAIL")}] {what}");
+        }
+
+        private void Finish()
+        {
+            done = true;
+            GameLogger.Log("TEST", $"[TEST_RESULT] name={ResultName} passed={passed} failed={failed}");
+            GetTree().Quit(failed == 0 ? 0 : 1);
+        }
+    }
+}