Many more tests and fixes

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

@@ -0,0 +1,106 @@
+using PkmnLib.Dynamic.Models;
+using PkmnLib.Plugin.Gen7.Scripts.Moves;
+
+namespace PkmnLib.Plugin.Gen7.Tests.Scripts.Moves;
+
+/// <summary>
+/// Tests for the <see cref="Frustration"/> move script.
+/// Gen VII Bulbapedia behavior: "Frustration inflicts damage and has no secondary effect. The base power of
+/// Frustration is dependent on the user's friendship. The lower the user's friendship is, the greater the
+/// base power of Frustration." The power formula is Power = (255 − Friendship) × 2 / 5, and from Generation
+/// III to VII, "if calculations yielded zero, the move's power becomes 1 instead".
+/// </summary>
+public class FrustrationTests
+{
+    /// <summary>
+    /// Creates a fully mocked test setup with a user that has the given friendship value.
+    /// </summary>
+    private static (Frustration script, IExecutingMove move, IPokemon target) CreateTestSetup(byte friendship)
+    {
+        var script = new Frustration();
+        var move = Substitute.For<IExecutingMove>();
+        var target = Substitute.For<IPokemon>();
+        var user = Substitute.For<IPokemon>();
+        user.Happiness.Returns(friendship);
+        move.User.Returns(user);
+        return (script, move, target);
+    }
+
+    /// <summary>
+    /// Bulbapedia: "The base power of Frustration is dependent on the user's friendship. The lower the
+    /// user's friendship is, the greater the base power of Frustration." The power formula is
+    /// Power = (255 − Friendship) × 2 / 5, with integer truncation.
+    /// </summary>
+    [Test, Arguments((byte)0, (ushort)102), Arguments((byte)50, (ushort)82), Arguments((byte)100, (ushort)62),
+     Arguments((byte)128, (ushort)50), Arguments((byte)200, (ushort)22), Arguments((byte)250, (ushort)2)]
+    public async Task ChangeBasePower_FriendshipValue_MatchesFormula(byte friendship, ushort expectedPower)
+    {
+        // Arrange
+        var (script, move, target) = CreateTestSetup(friendship);
+        ushort basePower = 102;
+
+        // Act
+        script.ChangeBasePower(move, target, 0, ref basePower);
+
+        // Assert
+        await Assert.That(basePower).IsEqualTo(expectedPower);
+    }
+
+    /// <summary>
+    /// Bulbapedia (Generations III to VII): the formula was adjusted so "if calculations yielded zero, the
+    /// move's power becomes 1 instead". Friendship values of 253 and above yield 0 from the formula, so the
+    /// power becomes 1.
+    /// </summary>
+    [Test, Arguments((byte)253), Arguments((byte)254), Arguments((byte)255)]
+    public async Task ChangeBasePower_FriendshipNearMaximum_PowerIsMinimumOne(byte friendship)
+    {
+        // Arrange
+        var (script, move, target) = CreateTestSetup(friendship);
+        ushort basePower = 102;
+
+        // Act
+        script.ChangeBasePower(move, target, 0, ref basePower);
+
+        // Assert
+        await Assert.That(basePower).IsEqualTo((ushort)1);
+    }
+
+    /// <summary>
+    /// Bulbapedia: "The lower the user's friendship is, the greater the base power of Frustration." — at 0
+    /// friendship the move reaches its maximum power of 102.
+    /// </summary>
+    [Test]
+    public async Task ChangeBasePower_ZeroFriendship_PowerIsMaximum102()
+    {
+        // Arrange
+        var (script, move, target) = CreateTestSetup(0);
+        ushort basePower = 102;
+
+        // Act
+        script.ChangeBasePower(move, target, 0, ref basePower);
+
+        // Assert
+        await Assert.That(basePower).IsEqualTo((ushort)102);
+    }
+
+    /// <summary>
+    /// The power is derived purely from the user's friendship: the incoming base power value does not
+    /// influence the result.
+    /// </summary>
+    [Test]
+    public async Task ChangeBasePower_DifferentIncomingBasePower_ResultDependsOnlyOnFriendship()
+    {
+        // Arrange
+        var (script, move, target) = CreateTestSetup(100);
+        ushort basePowerLow = 1;
+        ushort basePowerHigh = 250;
+
+        // Act
+        script.ChangeBasePower(move, target, 0, ref basePowerLow);
+        script.ChangeBasePower(move, target, 0, ref basePowerHigh);
+
+        // Assert
+        await Assert.That(basePowerLow).IsEqualTo((ushort)62);
+        await Assert.That(basePowerHigh).IsEqualTo((ushort)62);
+    }
+}