PkmnLib.NET/Plugins/PkmnLib.Plugin.Gen7.Tests/Scripts/Moves/MiracleEyeTests.cs

using PkmnLib.Dynamic.Models;
using PkmnLib.Dynamic.ScriptHandling;
using PkmnLib.Plugin.Gen7.Scripts.Moves;
using PkmnLib.Plugin.Gen7.Scripts.Pokemon;
using PkmnLib.Static;
using PkmnLib.Static.Utils;

namespace PkmnLib.Plugin.Gen7.Tests.Scripts.Moves;

/// <summary>
/// Tests for the <see cref="MiracleEye"/> move script.
/// Behavior is verified against the Bulbapedia page for Miracle Eye (Generation VII behavior: the
/// Generation IV base effect with the Generation V-to-VII changes applied).
/// The lasting part of the effect (removing the Dark type's immunity to Psychic moves and ignoring
/// evasion raises) is implemented by the <see cref="MiracleEyeEffect"/> volatile script, which the
/// move script is responsible for attaching to the target.
/// </summary>
public class MiracleEyeTests
{
    /// <summary>
    /// Creates a fully mocked test setup for Miracle Eye tests, with the target at the given evasion
    /// stat stage.
    /// </summary>
    private static (MiracleEye script, IExecutingMove move, IPokemon target, IScriptSet volatileSet, IHitData hitData)
        CreateTestSetup(sbyte evasionStage = 0)
    {
        var script = new MiracleEye();
        var move = Substitute.For<IExecutingMove>();
        var target = Substitute.For<IPokemon>();
        var hitData = Substitute.For<IHitData>();
        move.GetHitData(target, 0).Returns(hitData);

        var volatileSet = Substitute.For<IScriptSet>();
        target.Volatile.Returns(volatileSet);
        target.StatBoost.Returns(new StatBoostStatisticSet
        {
            Evasion = evasionStage,
        });

        return (script, move, target, volatileSet, hitData);
    }

    /// <summary>
    /// Helper to extract all stat boost changes requested on the target through
    /// <see cref="IPokemon.ChangeStatBoost"/>.
    /// </summary>
    private static IReadOnlyList<(Statistic stat, sbyte amount)> GetStatBoostChanges(IPokemon target) =>
        target.ReceivedCalls().Where(c => c.GetMethodInfo().Name == "ChangeStatBoost")
            .Select(c => ((Statistic)c.GetArguments()[0]!, (sbyte)c.GetArguments()[1]!)).ToList();

    /// <summary>
    /// Bulbapedia: "If Miracle Eye's target is a Dark-type Pokémon, it also removes the target's
    /// immunity to Psychic-type moves. Miracle Eye's effect ends when the target switches out."
    /// The lasting effect is implemented by attaching a <see cref="MiracleEyeEffect"/> volatile script
    /// to the target.
    /// </summary>
    [Test]
    public async Task OnSecondaryEffect_Always_AddsMiracleEyeEffectToTargetVolatile()
    {
        // Arrange
        var (script, move, target, volatileSet, _) = CreateTestSetup();

        // Act
        script.OnSecondaryEffect(move, target, 0);

        // Assert
        var addCall = volatileSet.ReceivedCalls().FirstOrDefault(c => c.GetMethodInfo().Name == "Add");
        await Assert.That(addCall).IsNotNull();
        await Assert.That(addCall!.GetArguments()[0] is MiracleEyeEffect).IsTrue();
    }

    /// <summary>
    /// Bulbapedia: "Miracle Eye causes accuracy checks against the target to ignore changes to the
    /// target's evasion stat stages if its evasion stat stage is greater than 0."
    /// The engine models this by resetting a raised evasion stat stage back to zero (and preventing
    /// further raises through <see cref="MiracleEyeEffect"/>).
    /// </summary>
    [Test, Arguments((sbyte)1, (sbyte)-1), Arguments((sbyte)3, (sbyte)-3), Arguments((sbyte)6, (sbyte)-6)]
    public async Task OnSecondaryEffect_PositiveEvasionStage_EvasionStageResetToZero(sbyte evasionStage,
        sbyte expectedChange)
    {
        // Arrange
        var (script, move, target, _, _) = CreateTestSetup(evasionStage);

        // Act
        script.OnSecondaryEffect(move, target, 0);

        // Assert
        var changes = GetStatBoostChanges(target);
        await Assert.That(changes.Count).IsEqualTo(1);
        await Assert.That(changes[0].stat).IsEqualTo(Statistic.Evasion);
        await Assert.That(changes[0].amount).IsEqualTo(expectedChange);
    }

    /// <summary>
    /// Bulbapedia: "Miracle Eye causes accuracy checks against the target to ignore changes to the
    /// target's evasion stat stages if its evasion stat stage is greater than 0."
    /// With a zero or lowered (negative) evasion stat stage the condition does not hold, so the stage
    /// must be left untouched: a lowered evasion stage remains in effect.
    /// </summary>
    [Test, Arguments((sbyte)0), Arguments((sbyte)-1), Arguments((sbyte)-6)]
    public async Task OnSecondaryEffect_NonPositiveEvasionStage_EvasionStageUnchanged(sbyte evasionStage)
    {
        // Arrange
        var (script, move, target, _, _) = CreateTestSetup(evasionStage);

        // Act
        script.OnSecondaryEffect(move, target, 0);

        // Assert
        await Assert.That(target.ReceivedCalls().Any(c => c.GetMethodInfo().Name == "ChangeStatBoost")).IsFalse();
    }

    /// <summary>
    /// Bulbapedia (Generations V to VII): "Miracle Eye will now fail if used against a Pokémon already
    /// under its effect."
    /// When the target already has the <see cref="MiracleEyeEffect"/> volatile script, the hit must fail.
    /// </summary>
    [Test]
    public async Task OnSecondaryEffect_TargetAlreadyUnderEffect_HitFails()
    {
        // Arrange
        var (script, move, target, volatileSet, hitData) = CreateTestSetup();
        volatileSet.Contains<MiracleEyeEffect>().Returns(true);
        volatileSet.Contains(Arg.Any<StringKey>()).Returns(true);

        // Act
        script.OnSecondaryEffect(move, target, 0);

        // Assert
        await Assert.That(hitData.ReceivedCalls().Any(c => c.GetMethodInfo().Name == "Fail")).IsTrue();
    }
}