diff --git a/UnitTestProject/Modules/SwapModule/DividendEodNoDoubleCountTest.cs b/UnitTestProject/Modules/SwapModule/DividendEodNoDoubleCountTest.cs
new file mode 100644
index 00000000..cb588031
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+++ b/UnitTestProject/Modules/SwapModule/DividendEodNoDoubleCountTest.cs
@@ -0,0 +1,163 @@
+using YLErp.DBModels;
+using YLErp.DBModels.Enums;
+
+namespace YLErp.Modules.SwapModule
+{
+    /// <summary>
+    /// 端到端：盘中收益互换（DividendIn 由生产方法 GetPreEodDividendSum 真实算出）→ 保存 → EOD，
+    /// 验证分红【不重复累计】（EOD TdCloseDividend 扣减 DividendIn）且【不丢失】（当日新计进 PosiDividendSum）。
+    ///
+    /// 与 MultiUnwindDividendConservationTest.MU_001 的区别：MU_001 的互换 DividendIn 是测试喂的常量；
+    /// 本测试的 DividendIn 由生产方法 GetPreEodDividendSum 真实算出（读 EOD 快照），再喂给 EOD——
+    /// 覆盖"预览算 DividendIn + EOD 扣减"的完整链路（MU_001 的缺口）。
+    /// </summary>
+    [TestClass]
+    public class DividendEodNoDoubleCountTest
+    {
+        private const int SwapTradeId = 9200;
+        private const long PositionId = 9201;
+        private const decimal InitialQty = 1000m;
+        private const decimal DailyRatePerUnit = 0.01m; // 每单位每天 0.01，便于手算
+        private static readonly DateTime StartDate = new(2026, 1, 5);
+
+        #region Stubs
+
+        /// <summary>SwapDealService stub：暴露 GetPreEodDividendSum，注入 EOD 数据（不连库）。</summary>
+        private sealed class DealSvcStub : SwapDealService
+        {
+            private readonly List<eod_swap> _eodSwaps;
+            private readonly List<eod_swap_position> _eodPositions;
+            public DealSvcStub(List<eod_swap> eodSwaps, List<eod_swap_position> eodPositions)
+                : base(OptUserInfo.UnitTestUser) { _eodSwaps = eodSwaps; _eodPositions = eodPositions; }
+            public decimal ExposeGetPreEodDividendSum(int tradeId, long positionId, DateTime dealDate)
+                => GetPreEodDividendSum(tradeId, positionId, dealDate);
+            protected override IQueryable<eod_swap> QueryPreEodSwaps(int tradeId)
+                => _eodSwaps.Where(x => x.SwapTradeId == tradeId).AsQueryable();
+            protected override eod_swap_position QueryPreEodPosition(int tradeId, long positionId, DateTime valueDate)
+                => _eodPositions.FirstOrDefault(x => x.SwapTradeId == tradeId && x.PositionId == positionId && x.ValueDate == valueDate);
+        }
+
+        /// <summary>SwapEodPositionService stub：暴露 UpdateEodPosition/CopyEodPosition + 线性 CalcBondPayment。</summary>
+        private sealed class EodSvcStub : TestableSwapEodPositionService
+        {
+            public EodSvcStub() : base(nameof(DividendEodNoDoubleCountTest)) { }
+            protected override decimal CalcBondPayment(string underlyingCode, DateTime fromDate, DateTime toDate, decimal qty, int shortRatio, int directionRatio)
+            {
+                int days = Math.Max(0, (int)(toDate - fromDate).TotalDays);
+                return DailyRatePerUnit * days * qty * shortRatio * directionRatio;
+            }
+            protected override underlying_manager GetUnderlyingData(string underlyingCode)
+                => new underlying_manager { ValueAddedTax = 0m };
+            protected override decimal GetUnderlyingPrice(string code, DateTime settleDate, out decimal vobp)
+            { vobp = 0m; return 1.00m; }
+            public eod_swap_position ExecuteUpdateEodPosition(swap_position swapPosition, eod_swap_position eod, trade td, DateTime valueDate, DateTime preSettleDate, List<swap_flow_event> unwindEvents)
+                => UpdateEodPosition(swapPosition, eod, null, td, valueDate, preSettleDate, unwindEvents);
+            public eod_swap_position ExecuteCopyEodPosition(eod_swap_position eod, trade td, DateTime valueDate, DateTime preSettleDate)
+                => CopyEodPosition(eod, null, td, valueDate, preSettleDate);
+        }
+
+        #endregion
+
+        #region 数据构建
+
+        private static trade CreateTrade() => new trade
+        {
+            id = SwapTradeId, TradeNumber = "UT-DIV-EOD-001", ClientId = 999999,
+            TradeType = "收益互换", TradeDate = StartDate, StartDate = StartDate,
+            ExerciseDate = new DateTime(2027, 1, 5), TradeStatus = "确认成交", ValidState = "Valid",
+            StructureType = "单标的", QuoteCurrency = "CNY", SettlementCurrency = "CNY",
+            OriginalStockEqvNotional = (double)(InitialQty * 1.00m)
+        };
+
+        private static swap_position CreatePosition() => new swap_position
+        {
+            id = PositionId, SwapTradeId = SwapTradeId,
+            PosiDirection = (int)SwapDirectionEnum.收取, PositionType = (int)PositionTypeFlag.Long,
+            UnderlyingCode = "210210.IB", ContractSize = 1m,
+            PosiQuantity = InitialQty, PosiNotionalValue = InitialQty,
+            PosiNetPrice = 1.000m, PosiGrossPrice = 1.000m,
+            PosiNetFeePrice = 1.000m, PosiNetNoFeePrice = 1.000m,
+            IsInitial = true, Invalid = false,
+            PosiTradingFee = 0, PosiTradingFeePending = 0
+        };
+
+        private static eod_swap_position CreateInitialEod() => new eod_swap_position
+        {
+            id = 1, SwapTradeId = SwapTradeId, PositionId = PositionId,
+            ValueDate = StartDate, PosiQuantity = InitialQty,
+            PosiDirection = (int)SwapDirectionEnum.收取, PositionType = (int)PositionTypeFlag.Long,
+            UnderlyingCode = "210210.IB", ContractSize = 1m,
+            PosiNetPrice = 1.000m, PosiGrossPrice = 1.000m,
+            PosiNetFeePrice = 1.000m, PosiNetNoFeePrice = 1.000m,
+            PosiDividendSum = 0m, TdPosiDividend = 0m, TdCloseDividend = 0m,
+            RealizedDividend = 0m, PosiFeePending = 0m,
+            InterestProfitSum = 0m, Invalid = false
+        };
+
+        private static swap_flow_event SwapEvent(decimal dividendIn, DateTime eventDate) => new swap_flow_event
+        {
+            SwapTradeId = SwapTradeId, EventType = (int)SwapFlowEventTypeEnum.互换,
+            PositionId = PositionId, Quantity = 0m, DividendIn = dividendIn,
+            MarkClosePnl = 0m, CloseFee = 0m, TradingFeePending = 0m,
+            EventDate = eventDate, PayDate = eventDate,
+            DataState = (int)SwapFlowDateStateEnum.完成
+        };
+
+        private static void AssertDecimalEqual(decimal expected, decimal actual, decimal tol, string msg)
+            => Assert.IsTrue(Math.Abs(expected - actual) <= tol, $"{msg}: expected={expected} actual={actual}");
+
+        #endregion
+
+        /// <summary>
+        /// 盘中收益互换：DividendIn 由 GetPreEodDividendSum 真实算（读 T-1 EOD）→ 保存 → EOD。
+        /// 验证：不重复（EOD TdCloseDividend 扣 DividendIn）+ 不丢失（当日新计进 PosiDividendSum）+ 守恒。
+        ///
+        /// 序列（StartDate=1/5，每日 0.01×1000=10）：
+        ///   D1=1/6 无事件 Copy：PosiDividendSum = 0 + 10 = 10
+        ///   D2=1/7 盘中互换：GetPreEodDividendSum(读 D1) → DividendIn=10；保存 swap_event；EOD：新计 10 - 实现 10 → PosiDividendSum=10
+        /// 守恒：全程新计(10+10) - 全程实现(10) = 末尾 PosiDividendSum(10)
+        /// </summary>
+        [TestMethod]
+        public void 盘中收益互换_DividendIn真实算_保存后EOD_不重复不丢失()
+        {
+            var eodSvc = new EodSvcStub();
+            var td = CreateTrade();
+            var position = CreatePosition();
+            var initialEod = CreateInitialEod();
+
+            // D1=1/6 无事件 EOD
+            var d1 = new DateTime(2026, 1, 6);
+            var r1 = eodSvc.ExecuteCopyEodPosition(initialEod, td, d1, StartDate);
+            AssertDecimalEqual(10m, r1.PosiDividendSum, 0.01m, "D1 PosiDividendSum(0+1天×10)");
+
+            // D2=1/7 盘中：DividendIn 由生产方法 GetPreEodDividendSum 真实算（读 D1 EOD，当日 EOD 未生成）
+            var d2 = new DateTime(2026, 1, 7);
+            var dealSvc = new DealSvcStub(
+                new List<eod_swap> { new eod_swap { SwapTradeId = SwapTradeId, ValueDate = d1 } },
+                new List<eod_swap_position> { r1 });
+            decimal dividendIn = dealSvc.ExposeGetPreEodDividendSum(SwapTradeId, PositionId, d2);
+            AssertDecimalEqual(10m, dividendIn, 0.01m, "盘中 DividendIn=GetPreEodDividendSum 读 T-1(D1)=10");
+            Console.WriteLine($"[盘中预览] DividendIn={dividendIn}（读 T-1 EOD PosiDividendSum={r1.PosiDividendSum}）");
+
+            // 保存互换事件（DividendIn=真实算出的值，模拟界面点收益互换后保存）
+            var swapEvent = SwapEvent(dividendIn, d2);
+
+            // D2=1/7 EOD（UpdateEodPosition，真实生产递推）
+            var r2 = eodSvc.ExecuteUpdateEodPosition(position, r1, td, d2, d1, new List<swap_flow_event> { swapEvent });
+
+            // 断言：不重复 + 不丢失
+            AssertDecimalEqual(10m, r2.TdPosiDividend, 0.01m, "D2 当日新计(1天×10)");
+            AssertDecimalEqual(dividendIn, r2.TdCloseDividend, 0.01m, "D2 TdCloseDividend=互换DividendIn（扣减→不重复累计）");
+            AssertDecimalEqual(10m, r2.PosiDividendSum, 0.01m, "D2 PosiDividendSum=前日10+新计10-实现10=10（当日新计挂着→不丢失）");
+
+            // 守恒：全程新计 - 全程实现 = 末尾 PosiDividendSum
+            decimal totalNew = r1.TdPosiDividend + r2.TdPosiDividend;
+            decimal totalRealized = r2.TdCloseDividend;
+            AssertDecimalEqual(r2.PosiDividendSum, totalNew - totalRealized, 0.01m,
+                $"守恒：末尾 PosiDividendSum({r2.PosiDividendSum}) = 全程新计({totalNew}) - 全程实现({totalRealized})");
+
+            Console.WriteLine($"[EOD 后] TdPosiDividend={r2.TdPosiDividend} TdCloseDividend={r2.TdCloseDividend} PosiDividendSum={r2.PosiDividendSum}");
+            Console.WriteLine($"结论：互换实现 {dividendIn} 被扣减（不重复）；当日新计 {r2.TdPosiDividend} 挂 PosiDividendSum（不丢失）");
+        }
+    }
+}