przygody-pana-cegly/progression.tests/JsonPlaythroughStoreTests.cs

using Mr.BrickAdventures.Progression.Adapters;

namespace Mr.BrickAdventures.Progression.Tests;

/// <summary>
/// These run against a real directory on disk. The store takes a path rather than using Godot's
/// FileAccess, which is the whole reason this is testable at all.
/// </summary>
public sealed class JsonPlaythroughStoreTests : IDisposable
{
    private readonly string _directory =
        Path.Combine(Path.GetTempPath(), "ppc-progression-" + Guid.NewGuid().ToString("N"));

    private static readonly LevelId First = LevelId.Of("village_1");
    private static readonly LevelId Second = LevelId.Of("village_2");

    private static readonly PlaythroughId Id =
        PlaythroughId.Of(new Guid("55555555-5555-5555-5555-555555555555"));

    private static Campaign TwoLevels() => Campaign.Of(new[] { First, Second });

    public void Dispose()
    {
        if (Directory.Exists(_directory)) Directory.Delete(_directory, recursive: true);
    }

    [Fact]
    public void A_playthrough_survives_a_round_trip_through_a_real_file()
    {
        var store = new JsonPlaythroughStore(_directory);
        var campaign = TwoLevels();
        var playthrough = Playthrough.StartNew(Id, campaign, Lives.Of(3));
        var attempt = new Attempt(First);
        attempt.RecordCoinsFound(Coins.Of(50));
        attempt.TryRecordPurchase(SkillId.Of("brick_throw"), SkillLevel.Of(2), Coins.Of(30));
        playthrough.SettleCompletion(attempt, campaign);

        store.Save(playthrough);
        var result = store.Load(Id);

        Assert.Equal(LoadOutcome.Loaded, result.Outcome);
        Assert.Equal(Coins.Of(20), result.Value!.Bank);
        Assert.Equal(Second, result.Value.CurrentLevel);
        Assert.Equal(SkillLevel.Of(2), result.Value.OwnedSkills[SkillId.Of("brick_throw")]);
        Assert.True(result.Value.HasCleared(First));
    }

    [Fact]
    public void No_file_means_absent()
    {
        Assert.Equal(LoadOutcome.Absent, new JsonPlaythroughStore(_directory).Load(Id).Outcome);
    }

    [Fact]
    public void Unreadable_json_is_corrupt_not_absent()
    {
        var store = new JsonPlaythroughStore(_directory);
        store.Save(Playthrough.StartNew(Id, TwoLevels(), Lives.Of(3)));
        File.WriteAllText(Directory.GetFiles(_directory, "*.json").Single(), "{ this is not json");

        var result = store.Load(Id);

        Assert.Equal(LoadOutcome.Corrupt, result.Outcome);
        Assert.NotNull(result.Problem);
    }

    [Fact]
    public void A_save_from_a_newer_build_is_corrupt_rather_than_treated_as_no_save()
    {
        // The bug this replaces, exactly: SaveSystem compared versions with != and returned false,
        // ContinueGame read false as "no save", called StartNewGame, and overwrote the file. Here the
        // caller can tell the difference and say so instead.
        var store = new JsonPlaythroughStore(_directory);
        store.Save(Playthrough.StartNew(Id, TwoLevels(), Lives.Of(3)));
        var file = Directory.GetFiles(_directory, "*.json").Single();
        File.WriteAllText(file, File.ReadAllText(file).Replace("\"version\": 1", "\"version\": 99"));

        var result = store.Load(Id);

        Assert.Equal(LoadOutcome.Corrupt, result.Outcome);
        Assert.Contains("newer build", result.Problem);
    }

    [Fact]
    public void A_snapshot_the_domain_rejects_is_corrupt()
    {
        var store = new JsonPlaythroughStore(_directory);
        store.Save(Playthrough.StartNew(Id, TwoLevels(), Lives.Of(3)));
        var file = Directory.GetFiles(_directory, "*.json").Single();
        File.WriteAllText(file, File.ReadAllText(file).Replace("\"lives\": 3", "\"lives\": -1"));

        Assert.Equal(LoadOutcome.Corrupt, store.Load(Id).Outcome);
    }

    [Fact]
    public void Saving_leaves_no_temporary_file_behind()
    {
        var store = new JsonPlaythroughStore(_directory);
        store.Save(Playthrough.StartNew(Id, TwoLevels(), Lives.Of(3)));
        store.Save(Playthrough.StartNew(Id, TwoLevels(), Lives.Of(2)));

        Assert.Empty(Directory.GetFiles(_directory, "*.tmp"));
        Assert.Single(Directory.GetFiles(_directory, "*.json"));
        Assert.Equal(2, store.Load(Id).Value!.Lives.Value);
    }

    [Fact]
    public void Each_playthrough_gets_its_own_file_so_slots_do_not_disturb_each_other()
    {
        // The reason for a flat record per aggregate rather than one combined document.
        var other = PlaythroughId.Of(new Guid("66666666-6666-6666-6666-666666666666"));
        var store = new JsonPlaythroughStore(_directory);

        store.Save(Playthrough.StartNew(Id, TwoLevels(), Lives.Of(3)));
        store.Save(Playthrough.StartNew(other, TwoLevels(), Lives.Of(1)));

        Assert.Equal(2, Directory.GetFiles(_directory, "*.json").Length);
        Assert.Equal(3, store.Load(Id).Value!.Lives.Value);
        Assert.Equal(1, store.Load(other).Value!.Lives.Value);
    }
}