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

using PkmnLib.Dynamic.Models;
using PkmnLib.Dynamic.ScriptHandling;
using PkmnLib.Dynamic.ScriptHandling.Registry;
using PkmnLib.Plugin.Gen7.Scripts.Moves;
using PkmnLib.Plugin.Gen7.Scripts.Side;
using PkmnLib.Static;

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

/// <summary>
/// Tests for the <see cref="Mist"/> move script and the <see cref="MistEffect"/> side script it places.
/// Gen VII Bulbapedia behavior (Generation III onwards): "Mist now creates a Mist effect on the user's side
/// of the field that lasts for five turns. All Pokémon on the user's side of the field are protected while
/// Mist is active, including Pokémon switched in after it was created." "While Mist is in effect, other
/// Pokémon (including allies) cannot lower the stats of Pokémon protected by Mist using either moves or
/// Abilities (e.g. Intimidate)", though it does not prevent self-inflicted stat reductions.
/// </summary>
public class MistTests
{
    /// <summary>
    /// Creates a fully mocked test setup where the user's battle side has a real <see cref="ScriptSet"/> as
    /// its volatile scripts, so the Mist side effect can actually be attached and inspected.
    /// </summary>
    private static (Mist script, IExecutingMove move, IBattleSide side, IScriptSet sideScripts) CreateTestSetup()
    {
        var script = new Mist();
        var move = Substitute.For<IExecutingMove>();

        var side = Substitute.For<IBattleSide>();
        side.GetScripts().Returns(_ => new ScriptIterator(Array.Empty<IEnumerable<ScriptContainer>>()));
        IScriptSet sideScripts = new ScriptSet(side);
        side.VolatileScripts.Returns(sideScripts);

        var user = Substitute.For<IBattlePokemon>();
        move.User.Returns(user);
        user.BattleSide.Returns(side);

        return (script, move, side, sideScripts);
    }

    /// <summary>
    /// Bulbapedia: "Mist now creates a Mist effect on the user's side of the field that lasts for five
    /// turns." — using the move attaches the <see cref="MistEffect"/> side script to the user's side.
    /// </summary>
    [Test]
    public async Task OnSecondaryEffect_UserInBattle_AddsMistEffectToUsersSide()
    {
        // Arrange
        var (script, move, _, sideScripts) = CreateTestSetup();

        // Act
        script.OnSecondaryEffect(move, Substitute.For<IBattlePokemon>(), 0);

        // Assert
        await Assert.That(sideScripts.Contains(ScriptUtils.ResolveName<MistEffect>())).IsTrue();
    }

    /// <summary>
    /// Bulbapedia: "While Mist is in effect, other Pokémon (including allies) cannot lower the stats of
    /// Pokémon protected by Mist using either moves or Abilities (e.g. Intimidate)." — a stat reduction
    /// inflicted by another Pokémon is prevented by the <see cref="MistEffect"/> side script.
    /// </summary>
    [Test, Arguments(Statistic.Attack, (sbyte)-1), Arguments(Statistic.Defense, (sbyte)-2),
     Arguments(Statistic.Speed, (sbyte)-6), Arguments(Statistic.Accuracy, (sbyte)-1)]
    public async Task PreventStatBoostChange_StatLoweredByOpponent_Prevented(Statistic stat, sbyte amount)
    {
        // Arrange
        var effect = new MistEffect();
        var target = Substitute.For<IBattlePokemon>();
        var prevent = false;

        // Act
        effect.PreventStatBoostChange(target, stat, amount, false, ref prevent);

        // Assert
        await Assert.That(prevent).IsTrue();
    }

    /// <summary>
    /// Bulbapedia: Mist only stops other Pokémon from being able to "lower the stats of Pokémon protected by
    /// Mist" — stat increases are not affected by Mist.
    /// </summary>
    [Test, Arguments((sbyte)1), Arguments((sbyte)2), Arguments((sbyte)6)]
    public async Task PreventStatBoostChange_StatIncrease_NotPrevented(sbyte amount)
    {
        // Arrange
        var effect = new MistEffect();
        var target = Substitute.For<IBattlePokemon>();
        var prevent = false;

        // Act
        effect.PreventStatBoostChange(target, Statistic.Attack, amount, false, ref prevent);

        // Assert
        await Assert.That(prevent).IsFalse();
    }

    /// <summary>
    /// Technical test: a stat change of zero stages is not a stat reduction, so Mist does not prevent it.
    /// </summary>
    [Test]
    public async Task PreventStatBoostChange_ZeroChange_NotPrevented()
    {
        // Arrange
        var effect = new MistEffect();
        var target = Substitute.For<IBattlePokemon>();
        var prevent = false;

        // Act
        effect.PreventStatBoostChange(target, Statistic.Attack, 0, false, ref prevent);

        // Assert
        await Assert.That(prevent).IsFalse();
    }

    /// <summary>
    /// Bulbapedia: "While Mist is in effect, other Pokémon (including allies) cannot lower the stats of
    /// Pokémon protected by Mist" — Mist does not prevent self-inflicted stat reductions (such as the
    /// Defense/Special Defense drops from the protected Pokémon's own Superpower or Close Combat).
    /// </summary>
    [Test]
    public async Task PreventStatBoostChange_SelfInflictedReduction_NotPrevented()
    {
        // Arrange
        var effect = new MistEffect();
        var target = Substitute.For<IBattlePokemon>();
        var prevent = false;

        // Act
        effect.PreventStatBoostChange(target, Statistic.Defense, -1, true, ref prevent);

        // Assert
        await Assert.That(prevent).IsFalse();
    }

    /// <summary>
    /// Bulbapedia: "Mist now creates a Mist effect on the user's side of the field that lasts for five
    /// turns." — after five end-of-turn ticks the <see cref="MistEffect"/> removes itself from the side.
    /// </summary>
    [Test]
    public async Task MistEffect_AfterFiveEndOfTurns_EffectExpires()
    {
        // Arrange
        var (script, move, side, sideScripts) = CreateTestSetup();
        script.OnSecondaryEffect(move, Substitute.For<IBattlePokemon>(), 0);
        var effect = sideScripts.Get<MistEffect>();
        await Assert.That(effect).IsNotNull();

        // Act - five turns pass
        var battle = Substitute.For<IBattle>();
        if (effect is IScriptOnEndTurn endTurn)
        {
            for (var i = 0; i < 5; i++)
                endTurn.OnEndTurn(side, battle);
        }

        // Assert
        await Assert.That(sideScripts.Contains(ScriptUtils.ResolveName<MistEffect>())).IsFalse();
    }
}