Implement deterministic simulation spine

tests/SideScrollerGame.Sim.Tests/SimulationVerificationTests.cs

@@ -0,0 +1,27 @@
+using SideScrollerGame.Sim.Input;
+using SideScrollerGame.Sim.Verification;
+
+namespace SideScrollerGame.Sim.Tests;
+
+public sealed class SimulationVerificationTests
+{
+    [Fact]
+    public void RoundTripStateMode_AllowsStepping()
+    {
+        Simulation simulation = new(SimulationTestFactory.CreateGameDefinition(), SimulationTestFactory.CreateConfig(VerificationMode.RoundTripState), 22);
+
+        var result = simulation.Step(SimulationTestFactory.CreateTick(1, new MoveAxisChanged(new(1), 1, 0)));
+
+        Assert.Equal(1, result.CurrentSnapshot.Tick);
+    }
+
+    [Fact]
+    public void RoundTripAndStepCloneMode_AllowsStepping()
+    {
+        Simulation simulation = new(SimulationTestFactory.CreateGameDefinition(), SimulationTestFactory.CreateConfig(VerificationMode.RoundTripAndStepClone), 23);
+
+        var result = simulation.Step(SimulationTestFactory.CreateTick(1, new ButtonChanged(new(1), InputButton.Jump, true)));
+
+        Assert.Equal(1, result.CurrentSnapshot.Tick);
+    }
+}