Adjusts move-phase to better track last move for copycat, writes and updates unit tests for assist/copycat

src/phases/move-phase.ts

@@ -246,11 +246,6 @@ export class MovePhase extends BattlePhase {
       this.scene.eventTarget.dispatchEvent(new MoveUsedEvent(this.pokemon?.id, this.move.getMove(), this.move.ppUsed));
     }
 
-    // Update the battle's "last move" pointer, unless we're currently mimicking a move.
-    if (!allMoves[this.move.moveId].hasAttr(CopyMoveAttr)) {
-      this.scene.currentBattle.lastMove = this.move.moveId;
-    }
-
     /**
      * Determine if the move is successful (meaning that its damage/effects can be attempted)
      * by checking that all of the following are true:
@@ -274,6 +269,14 @@ export class MovePhase extends BattlePhase {
 
     const success = passesConditions && !failedDueToWeather && !failedDueToTerrain;
 
+    // Update the battle's "last move" pointer, unless we're currently mimicking a move.
+    if (!allMoves[this.move.moveId].hasAttr(CopyMoveAttr)) {
+      // The last move used is unaffected by moves that fail
+      if (success) {
+        this.scene.currentBattle.lastMove = this.move.moveId;
+      }
+    }
+
     /**
      * If the move has not failed, trigger ability-based user type changes and then execute it.
      *

src/test/moves/assist.test.ts

@@ -30,6 +30,7 @@ describe("Moves - Assist", () => {
       .battleType("single")
       .disableCrits()
       .enemySpecies(Species.MAGIKARP)
+      .enemyLevel(100)
       .enemyAbility(Abilities.BALL_FETCH)
       .enemyMoveset(Moves.SPLASH);
   });
@@ -39,7 +40,6 @@ describe("Moves - Assist", () => {
       .battleType("double")
       .enemyMoveset(Moves.SWORDS_DANCE);
     await game.classicMode.startBattle([ Species.FEEBAS, Species.SHUCKLE ]);
-    const leftPlayer = game.scene.getPlayerPokemon()!;
 
     game.move.select(Moves.ASSIST, 0);
     game.move.select(Moves.SKETCH, 1);
@@ -47,7 +47,7 @@ describe("Moves - Assist", () => {
     // Player_2 uses Sketch, copies Swords Dance, Player_1 uses Assist, uses Player_2's Sketched Swords Dance
     await game.toNextTurn();
 
-    expect(leftPlayer.getStatStage(Stat.ATK)).toBe(2); // Stat raised from Assist -> Swords Dance
+    expect(game.scene.getPlayerPokemon()!.getStatStage(Stat.ATK)).toBe(2); // Stat raised from Assist -> Swords Dance
   });
 
   it("should fail if there are no usable moves", async () => {
@@ -57,4 +57,14 @@ describe("Moves - Assist", () => {
     await game.toNextTurn();
     expect(game.scene.getPlayerPokemon()!.getLastXMoves()[0].result).toBe(MoveResult.FAIL);
   });
+
+  it("should apply secondary effects of a move", async () => {
+    game.override.moveset([ Moves.ASSIST, Moves.WOOD_HAMMER, Moves.WOOD_HAMMER, Moves.WOOD_HAMMER ]);
+    await game.classicMode.startBattle([ Species.FEEBAS ]);
+
+    game.move.select(Moves.ASSIST, 0);
+    await game.toNextTurn();
+
+    expect(game.scene.getPlayerPokemon()!.isFullHp()).toBeFalsy(); // should receive recoil damage from Wood Hammer
+  });
 });

src/test/moves/copycat.test.ts

@@ -0,0 +1,88 @@
+import { BattlerIndex } from "#app/battle";
+import { Stat } from "#app/enums/stat";
+import { MoveResult } from "#app/field/pokemon";
+import { Abilities } from "#enums/abilities";
+import { Moves } from "#enums/moves";
+import { Species } from "#enums/species";
+import GameManager from "#test/utils/gameManager";
+import Phaser from "phaser";
+import { afterEach, beforeAll, beforeEach, describe, expect, it, vi } from "vitest";
+
+describe("Moves - Copycat", () => {
+  let phaserGame: Phaser.Game;
+  let game: GameManager;
+
+  beforeAll(() => {
+    phaserGame = new Phaser.Game({
+      type: Phaser.HEADLESS,
+    });
+  });
+
+  afterEach(() => {
+    game.phaseInterceptor.restoreOg();
+  });
+
+  beforeEach(() => {
+    game = new GameManager(phaserGame);
+    game.override
+      .moveset([ Moves.COPYCAT, Moves.SPIKY_SHIELD, Moves.SWORDS_DANCE, Moves.SPLASH ])
+      .ability(Abilities.BALL_FETCH)
+      .battleType("single")
+      .disableCrits()
+      .starterSpecies(Species.FEEBAS)
+      .enemySpecies(Species.MAGIKARP)
+      .enemyAbility(Abilities.BALL_FETCH)
+      .enemyMoveset(Moves.SPLASH);
+  });
+
+  it("should copy the last move successfully executed", async () => {
+    game.override.enemyMoveset(Moves.SUCKER_PUNCH);
+    await game.classicMode.startBattle();
+
+    game.move.select(Moves.SWORDS_DANCE);
+    await game.toNextTurn();
+
+    game.move.select(Moves.COPYCAT); // Last successful move should be Swords Dance
+    await game.toNextTurn();
+
+    expect(game.scene.getPlayerPokemon()!.getStatStage(Stat.ATK)).toBe(4);
+  });
+
+  it("should fail when the last move used is not a valid Copycat move", async () => {
+    game.override.enemyMoveset(Moves.PROTECT); // Protect is not a valid move for Copycat to copy
+    await game.classicMode.startBattle();
+
+    game.move.select(Moves.SPIKY_SHIELD); // Spiky Shield is not a valid move for Copycat to copy
+    await game.toNextTurn();
+
+    game.move.select(Moves.COPYCAT);
+    await game.toNextTurn();
+
+    expect(game.scene.getPlayerPokemon()!.getLastXMoves()[0].result).toBe(MoveResult.FAIL);
+  });
+
+  it("should copy the called move when the last move successfully calls another", async () => {
+    game.override
+      .moveset([ Moves.SPLASH, Moves.METRONOME ])
+      .enemyMoveset(Moves.COPYCAT);
+    await game.classicMode.startBattle();
+    vi.spyOn(game.scene.getPlayerPokemon()!, "randSeedInt").mockReturnValue(Moves.SWORDS_DANCE);
+
+    game.move.select(Moves.METRONOME);
+    await game.setTurnOrder([ BattlerIndex.PLAYER, BattlerIndex.ENEMY ]); // Player moves first, so enemy can copy Swords Dance
+    await game.toNextTurn();
+
+    expect(game.scene.getEnemyPokemon()!.getStatStage(Stat.ATK)).toBe(2);
+  });
+
+  it("should apply secondary effects of a move", async () => {
+    game.override.enemyMoveset(Moves.ACID_SPRAY); // Secondary effect lowers SpDef by 2 stages
+    await game.classicMode.startBattle();
+
+    game.move.select(Moves.COPYCAT);
+    await game.setTurnOrder([ BattlerIndex.ENEMY, BattlerIndex.PLAYER ]);
+    await game.toNextTurn();
+
+    expect(game.scene.getEnemyPokemon()!.getStatStage(Stat.SPDEF)).toBe(-2);
+  });
+});