Finish rewrite task list

tests/ReactorMaintenance.Simulation.Tests/SimulationEngineTests.cs

@@ -121,6 +121,18 @@ public sealed class SimulationEngineTests
         Assert.Contains(report.Errors, error => error.Message.Contains("Ambiguous junction flow", StringComparison.Ordinal));
     }
 
+    [Fact]
+    public void ValidatorRejectsJunctionWithoutTwoOrThreeOutflows()
+    {
+        var level = BuildJunctionLevel(2);
+        level = level.SetUnderground(new(3, 3), ECarrierType.Fuel, new());
+
+        var report = new LevelValidator().Validate(level);
+
+        Assert.False(report.IsValid);
+        Assert.Contains(report.Errors, error => error.Message.Contains("one incoming branch and two or three outgoing branches", StringComparison.Ordinal));
+    }
+
     [Fact]
     public void NonJunctionCellsAcceptBestFlowFromMultipleSourcePaths()
     {
@@ -336,6 +348,33 @@ public sealed class SimulationEngineTests
         Assert.Equal(EPropType.Flow, loaded.GetProp(new(2, 2)).Type);
     }
 
+    [Fact]
+    public void LevelSerializationRoundTripsRuleEventsDoorsAndElectricityLeakFaces()
+    {
+        var level = BuildReadyLevel();
+        level = level.SetTerrain(new(6, 4), ECellTerrain.Wall);
+        level = level.SetUnderground(new(6, 4), ECarrierType.Electricity, new() { State = EUndergroundState.Leaking }) with {
+            Doors = [new() { A = new(5, 3), B = new(5, 4), State = EDoorState.Closed }],
+            Leaks = [new() { Carrier = ECarrierType.Electricity, UndergroundPosition = new(6, 4), AccessPosition = new(6, 3) }],
+            RuleEvents = [
+                new() {
+                    Id = "authored",
+                    Phase = ERuleEventPhase.EndOfTurn,
+                    Predicates = [new() { Kind = ERulePredicateKind.TurnAtLeast, Turn = 2 }],
+                    Effects = [new() { Kind = ERuleEffectKind.EmitWarning, Message = "serialized" }]
+                }
+            ]
+        };
+
+        var loaded = LevelSerializer.Deserialize(LevelSerializer.Serialize(level));
+
+        Assert.Single(loaded.Doors);
+        Assert.Single(loaded.Leaks);
+        Assert.Single(loaded.RuleEvents);
+        Assert.Equal(new(6, 3), loaded.Leaks[0].AccessPosition);
+        Assert.Equal("authored", loaded.RuleEvents[0].Id);
+    }
+
     [Fact]
     public void LevelSerializationRejectsOldSchema()
     {