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

using PkmnLib.Dynamic.Events;
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="Flatter"/> move script.
/// Gen VII Bulbapedia behavior: Flatter raises the target's Special Attack stat by one stage and confuses it.
/// </summary>
public class FlatterTests
{
    private static (Flatter script, IExecutingMove move, IPokemon target, IScriptSet targetVolatile) CreateTestSetup()
    {
        var script = new Flatter();
        var move = Substitute.For<IExecutingMove>();
        var user = Substitute.For<IPokemon>();
        move.User.Returns(user);

        var target = Substitute.For<IPokemon>();
        var targetVolatile = Substitute.For<IScriptSet>();
        target.Volatile.Returns(targetVolatile);

        return (script, move, target, targetVolatile);
    }

    /// <summary>
    /// Helper to extract the arguments of the received ChangeStatBoost call, or null when no stat boost
    /// was requested. Received-call inspection is used instead of NSubstitute argument matchers because
    /// the trailing <see cref="EventBatchId"/> parameter cannot be bound by <c>Arg.Any</c> (its
    /// parameterless constructor initializes a fresh id, so it never equals the matcher's default value).
    /// </summary>
    private static object?[]? GetStatBoostArgs(IPokemon pokemon)
    {
        var call = pokemon.ReceivedCalls().FirstOrDefault(c => c.GetMethodInfo().Name == "ChangeStatBoost");
        return call?.GetArguments();
    }

    /// <summary>
    /// Bulbapedia: Flatter "raises the target's Special Attack stat by one stage".
    /// The boost is caused by the opponent's move, so it is not self-inflicted.
    /// </summary>
    [Test]
    public async Task OnSecondaryEffect_Always_RaisesTargetSpecialAttackByOneStage()
    {
        // Arrange
        var (script, move, target, _) = CreateTestSetup();

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

        // Assert
        var args = GetStatBoostArgs(target);
        await Assert.That(args).IsNotNull();
        await Assert.That((Statistic)args![0]!).IsEqualTo(Statistic.SpecialAttack);
        await Assert.That((sbyte)args[1]!).IsEqualTo((sbyte)1);
        await Assert.That((bool)args[2]!).IsFalse(); // not self-inflicted
        await Assert.That((bool)args[3]!).IsFalse(); // not forced
    }

    /// <summary>
    /// Bulbapedia: Flatter raises the target's Special Attack "and confuses it". The confusion is applied
    /// through the target's <see cref="IPokemon.Volatile"/> script set.
    /// </summary>
    [Test]
    public async Task OnSecondaryEffect_Always_ConfusesTarget()
    {
        // Arrange
        var (script, move, target, targetVolatile) = CreateTestSetup();

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

        // Assert
        targetVolatile.Received(1).StackOrAdd(new StringKey("confusion"), Arg.Any<Func<Script?>>());
        await Assert.That(targetVolatile.ReceivedCalls().Any(c => c.GetMethodInfo().Name == "StackOrAdd")).IsTrue();
    }

    /// <summary>
    /// Bulbapedia: Flatter "confuses" the target. The instantiation function passed to the volatile script
    /// set creates a <see cref="Confusion"/> script.
    /// </summary>
    [Test]
    public async Task OnSecondaryEffect_ConfusionInstantiation_CreatesConfusionScript()
    {
        // Arrange
        var (script, move, target, targetVolatile) = CreateTestSetup();

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

        // Assert
        var call = targetVolatile.ReceivedCalls().First(c => c.GetMethodInfo().Name == "StackOrAdd");
        var instantiation = (Func<Script?>)call.GetArguments()[1]!;
        await Assert.That(instantiation() is Confusion).IsTrue();
    }

    /// <summary>
    /// Bulbapedia: "Even if the target's Special Attack is already at +6 stages, it will still become
    /// confused." A substitute's <see cref="IPokemon.ChangeStatBoost"/> returns false by default (the
    /// boost failed), yet the confusion is still applied.
    /// </summary>
    [Test]
    public async Task OnSecondaryEffect_StatBoostFails_TargetStillConfused()
    {
        // Arrange
        var (script, move, target, targetVolatile) = CreateTestSetup();

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

        // Assert - the unconfigured ChangeStatBoost returned false, but the target was still confused
        await Assert.That(GetStatBoostArgs(target)).IsNotNull();
        await Assert.That(targetVolatile.ReceivedCalls().Any(c => c.GetMethodInfo().Name == "StackOrAdd")).IsTrue();
    }

    /// <summary>
    /// Bulbapedia: "Even if the target is already confused, or cannot become confused due to Safeguard or
    /// Own Tempo, its Special Attack will still be raised." When the volatile set refuses to add the
    /// confusion script (returns null), the Special Attack boost still happens.
    /// </summary>
    [Test]
    public async Task OnSecondaryEffect_ConfusionNotAdded_SpecialAttackStillRaised()
    {
        // Arrange
        var (script, move, target, targetVolatile) = CreateTestSetup();
        targetVolatile.StackOrAdd(Arg.Any<StringKey>(), Arg.Any<Func<Script?>>()).Returns((ScriptContainer?)null);

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

        // Assert
        var args = GetStatBoostArgs(target);
        await Assert.That(args).IsNotNull();
        await Assert.That((Statistic)args![0]!).IsEqualTo(Statistic.SpecialAttack);
        await Assert.That((sbyte)args[1]!).IsEqualTo((sbyte)1);
    }
}