zfxaction26_1/tests/SideScrollerGame.Sim.Tests/SimulationSerializationTests.cs

using SideScrollerGame.Sim.Input;

namespace SideScrollerGame.Sim.Tests;

public sealed class SimulationSerializationTests
{
    [Fact]
    public void SaveStateLoadState_PreservesStateAndNextStepHash()
    {
        var definition = SimulationTestFactory.CreateGameDefinition();
        var config = SimulationTestFactory.CreateConfig();

        Simulation original = new(definition, config, 17);
        original.Step(SimulationTestFactory.CreateTick(1, new MoveAxisChanged(new(1), 1, 1)));

        var bytes = original.SaveState();
        var loaded = Simulation.LoadState(bytes, definition, config);

        Assert.Equal(original.CurrentTick, loaded.CurrentTick);
        Assert.Equal(original.CurrentSnapshot.StateHash, loaded.CurrentSnapshot.StateHash);

        var nextBatch = SimulationTestFactory.CreateTick(2, new ButtonChanged(new(1), InputButton.FirePrimary, true));
        var originalHash = original.Step(nextBatch).StateHash;
        var loadedHash = loaded.Step(nextBatch).StateHash;

        Assert.Equal(originalHash, loadedHash);
    }

    [Fact]
    public void Constructor_NormalizesZeroSeed()
    {
        Simulation simulation = new(SimulationTestFactory.CreateGameDefinition(), SimulationTestFactory.CreateConfig(), 0);

        simulation.Step(TickActionBatch.Empty(1));

        Assert.NotEqual(0UL, simulation.CurrentState.RandomState);
    }
}