test(battle-engine M13): NewNetworkEmitBattle harness + OnEmit capture seam

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

SVSim.BattleEngine.Tests/HeadlessFixture.cs

@@ -343,6 +343,46 @@ namespace SVSim.BattleEngine.Tests
             return mgr;
         }
 
+        // M13 emit-path read. Builds a HeadlessNetworkBattleMgr (the emitting twin of the
+        // HeadlessBattleMgr NewAuthoritativeBattle returns) and stands up the OnEmit capture seam: the
+        // engine's own RealTimeNetworkAgent.OnEmit event (RealTimeNetworkAgent.cs:1268) fires the played
+        // URI before both emit guards, so capturing it needs no Engine/shim edit — just an injected agent.
+        // Returns (mgr, emitted-URI list). The caller seeds the hand and drives mgr.OperateMgr.PlayCard.
+        public static (HeadlessNetworkBattleMgr mgr, System.Collections.Generic.List<NetworkBattleDefine.NetworkBattleURI> emitted)
+            NewNetworkEmitBattle(IRandomSource rng = null)
+        {
+            EnsureInitialized();                         // sets IsForecast = true among other globals
+            var mgr = new HeadlessNetworkBattleMgr(new HeadlessContentsCreator(), rng);
+            mgr.IsRecovery = true;                        // collapse wait delays to 0 (F1)
+
+            var player = mgr.BattlePlayer;
+            var enemy = mgr.BattleEnemy;
+            SetField(player, "_opponentBattlePlayer", enemy);
+            SetField(enemy, "_opponentBattlePlayer", player);
+            player.IsSelfTurn = true;
+            enemy.IsSelfTurn = false;
+
+            InitLeaderLife(mgr);                          // a 0-life leader reads as game-over and blocks plays
+            InitCardTemplates(mgr);                       // play/draw VFX touches the card view layer
+
+            // Inject a headless RealTimeNetworkAgent so NetworkBattleSender's ToolboxGame.RealTimeNetworkAgent
+            // .* calls resolve, and subscribe OnEmit. GetUninitializedObject skips the MonoBehaviour Awake.
+            var agent = (RealTimeNetworkAgent)System.Runtime.Serialization.FormatterServices
+                .GetUninitializedObject(typeof(RealTimeNetworkAgent));
+            // CurrentMatchingStatus has a protected setter; seed it non-Disconnected so EmitMsgPack does not
+            // early-return at RealTimeNetworkAgent.cs:1272 (needed only for the best-effort payload read, Task 4;
+            // OnEmit fires regardless). The default on the uninitialized object is OffLine (0), which clears the
+            // SetCurrentMatchingStatus guards; the only side effect is a static-StringBuilder trace log, so the
+            // public setter runs cleanly headless. Prepared (50) is the real enum member (RealTimeNetworkAgent.cs:35).
+            agent.SetCurrentMatchingStatus(RealTimeNetworkAgent.MatchingStatus.Prepared);
+
+            var emitted = new System.Collections.Generic.List<NetworkBattleDefine.NetworkBattleURI>();
+            agent.OnEmit += uri => emitted.Add(uri);
+            Wizard.ToolboxGame.SetRealTimeNetworkBattle(agent);
+
+            return (mgr, emitted);
+        }
+
         private static void SetField(object obj, string name, object value)
         {
             var f = obj.GetType().GetField(name,

SVSim.BattleEngine.Tests/NetworkMgrConstructionProbeTests.cs

@@ -21,5 +21,15 @@ namespace SVSim.BattleEngine.Tests
                 Assert.That(mgr, Is.Not.Null);
             });
         }
+
+        [Test]
+        public void OnEmit_capture_seam_is_wired_via_injected_agent()
+        {
+            var (mgr, emitted) = HeadlessEngineEnv.NewNetworkEmitBattle();
+            Assert.That(mgr, Is.Not.Null);
+            Assert.That(Wizard.ToolboxGame.RealTimeNetworkAgent, Is.Not.Null,
+                "agent must be injected so NetworkBattleSender's ToolboxGame.RealTimeNetworkAgent.* calls resolve");
+            Assert.That(emitted, Is.Empty, "no emit yet — only the seam is wired");
+        }
     }
 }