第十阶段 stage 1（二）：永续合约单仓位、保证金金额一行、名义价值

tests/Decentralized.Domain.Tests/Program.cs

@@ -949,6 +949,7 @@ internal static class Program
             double fee = 5000 * Tuning.PerpFee;
             Check(Math.Abs(pos.Size - 50) < 1e-9 && Math.Abs(a.Get(Assets.CRC) - (1000 - fee)) < 1e-9 && Math.Abs(pos.Taint - 500) < 1e-9, $"名义 5000，手续费 {fee}，污点 500 随保证金进仓位");
             Check(b.Open(a, "PSC", false, 100, 2, 100, 1, pr) == PerpResult.Opposite, "不能同时多空");
+            Check(b.Open(a, "PSC", true, 100, 2, 100, 1, pr) == PerpResult.Single && b.Open(a, "SPARK", true, 100, 1, 10, 1, pr) == PerpResult.Single && b.Positions.Count == 1, "只有一个仓位：加仓、开别的标的都被拒，只能追加保证金");
             Check(Math.Abs(pos.LiqPrice - (50 * 100 - 1000) / (50 * (1 - Tuning.PerpMaint))) < 1e-9 && pos.LiqPrice > 85 && pos.LiqPrice < 90, $"强平价 {pos.LiqPrice:0.0}（约 −11%）");
             // 平仓盈利：干净的新币，污点原额退回
             double paid = b.Close(a, "PSC", 110, 2, out double d0);