Many more tests and fixes

Plugins/PkmnLib.Plugin.Gen7.Tests/Scripts/Moves/KnockOffTests.cs

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+using PkmnLib.Dynamic.Models;
+using PkmnLib.Dynamic.ScriptHandling;
+using PkmnLib.Plugin.Gen7.Scripts.Moves;
+using PkmnLib.Static;
+
+namespace PkmnLib.Plugin.Gen7.Tests.Scripts.Moves;
+
+/// <summary>
+/// Tests for the <see cref="KnockOff"/> move script.
+/// Behavior is verified against the Bulbapedia page for Knock Off (Generation VII).
+/// </summary>
+public class KnockOffTests
+{
+    /// <summary>
+    /// Creates a fully mocked test setup for Knock Off tests. When <paramref name="targetHasItem"/> is true,
+    /// <see cref="IPokemon.TryStealHeldItem"/> succeeds and yields a mocked item.
+    /// </summary>
+    private static (KnockOff script, IExecutingMove move, IPokemon target, IPokemon user, IHitData hitData)
+        CreateTestSetup(bool targetHasItem)
+    {
+        var script = new KnockOff();
+        var move = Substitute.For<IExecutingMove>();
+        var target = Substitute.For<IPokemon>();
+        var hitData = Substitute.For<IHitData>();
+        move.GetHitData(target, 0).Returns(hitData);
+
+        target.TryStealHeldItem(out Arg.Any<IItem?>()).Returns(callInfo =>
+        {
+            callInfo[0] = targetHasItem ? Substitute.For<IItem>() : null;
+            return targetHasItem;
+        });
+
+        var user = Substitute.For<IPokemon>();
+        move.User.Returns(user);
+
+        return (script, move, target, user, hitData);
+    }
+
+    /// <summary>
+    /// Bulbapedia: "Knock Off inflicts damage and knocks off the target's held item if it has one."
+    /// (Generation V onwards: "Knock Off now removes the held item rather than rendering it unusable".)
+    /// </summary>
+    [Test]
+    public async Task OnSecondaryEffect_TargetHoldsItem_ItemIsRemoved()
+    {
+        // Arrange
+        var (script, move, target, _, hitData) = CreateTestSetup(true);
+
+        // Act
+        script.OnSecondaryEffect(move, target, 0);
+
+        // Assert
+        target.Received(1).TryStealHeldItem(out Arg.Any<IItem?>());
+        hitData.DidNotReceive().Fail();
+        await Assert.That(target.ReceivedCalls().Any(c => c.GetMethodInfo().Name == "TryStealHeldItem")).IsTrue();
+    }
+
+    /// <summary>
+    /// Bulbapedia: "Knock Off inflicts damage and knocks off the target's held item if it has one."
+    /// Against a target without a held item the move simply deals its damage without any further effect; it
+    /// does not fail.
+    /// </summary>
+    [Test]
+    public async Task OnSecondaryEffect_TargetHoldsNoItem_HitIsNotMarkedAsFailed()
+    {
+        // Arrange
+        var (script, move, target, _, hitData) = CreateTestSetup(false);
+
+        // Act
+        script.OnSecondaryEffect(move, target, 0);
+
+        // Assert
+        hitData.DidNotReceive().Fail();
+        await Assert.That(hitData.ReceivedCalls().Any(c => c.GetMethodInfo().Name == "Fail")).IsFalse();
+    }
+
+    /// <summary>
+    /// Bulbapedia (Generation V onwards): "If the user faints due to the target's Ability (Rough Skin or
+    /// Iron Barbs) or held Rocky Helmet, it cannot remove the target's held item."
+    /// Those effects damage the user before the secondary effect runs, so a user that has fainted by then must
+    /// not remove the item.
+    /// </summary>
+    [Test]
+    public async Task OnSecondaryEffect_UserIsFainted_ItemIsNotRemoved()
+    {
+        // Arrange
+        var (script, move, target, user, _) = CreateTestSetup(true);
+        user.IsFainted.Returns(true);
+
+        // Act
+        script.OnSecondaryEffect(move, target, 0);
+
+        // Assert
+        await Assert.That(target.ReceivedCalls().Any(c => c.GetMethodInfo().Name == "TryStealHeldItem")).IsFalse();
+    }
+
+    /// <summary>
+    /// Bulbapedia (Generation VI onwards): "If Knock Off is used on a Pokémon that is holding an item that can
+    /// be knocked off, its base power will be boosted by 50%."
+    /// With Knock Off's base power of 65 the boosted power is 97 (65 × 1.5, fractions dropped).
+    /// </summary>
+    [Test]
+    public async Task ChangeBasePower_TargetHoldsRemovableItem_BasePowerBoostedByFiftyPercent()
+    {
+        // Arrange
+        var (script, move, target, _, _) = CreateTestSetup(true);
+        target.HeldItem.Returns(Substitute.For<IItem>());
+        ushort basePower = 65;
+
+        // Act
+        ((IScriptChangeBasePower)script).ChangeBasePower(move, target, 0, ref basePower);
+
+        // Assert
+        await Assert.That(basePower).IsEqualTo((ushort)97);
+    }
+
+    /// <summary>
+    /// Bulbapedia (Generation VI onwards): "If Knock Off is used on a Pokémon that is holding an item that can
+    /// be knocked off, its base power will be boosted by 50%."
+    /// A target without a held item does not grant the boost, so the base power stays unchanged.
+    /// </summary>
+    [Test]
+    public async Task ChangeBasePower_TargetHoldsNoItem_BasePowerUnchanged()
+    {
+        // Arrange
+        var (script, move, target, _, _) = CreateTestSetup(false);
+        target.HeldItem.Returns((IItem?)null);
+        ushort basePower = 65;
+
+        // Act
+        ((IScriptChangeBasePower)script).ChangeBasePower(move, target, 0, ref basePower);
+
+        // Assert
+        await Assert.That(basePower).IsEqualTo((ushort)65);
+    }
+}