Add Several Unit Tests and Fixes

src/modifier/modifier.ts

@@ -2891,13 +2891,22 @@ export function overrideModifiers(scene: BattleScene, isPlayer: boolean = true):
 
   modifiersOverride.forEach(item => {
     const modifierFunc = modifierTypes[item.name];
-    const modifier = modifierFunc().withIdFromFunc(modifierFunc).newModifier() as PersistentModifier;
-    modifier.stackCount = item.count || 1;
+    let modifierType: ModifierType | null = modifierFunc();
 
-    if (isPlayer) {
-      scene.addModifier(modifier, true, false, false, true);
-    } else {
-      scene.addEnemyModifier(modifier, true, true);
+    if (modifierType instanceof ModifierTypes.ModifierTypeGenerator) {
+      const pregenArgs = ("type" in item) && (item.type !== null) ? [item.type] : undefined;
+      modifierType = modifierType.generateType([], pregenArgs);
+    }
+
+    const modifier = modifierType && modifierType.withIdFromFunc(modifierFunc).newModifier() as PersistentModifier;
+    if (modifier) {
+      modifier.stackCount = item.count || 1;
+
+      if (isPlayer) {
+        scene.addModifier(modifier, true, false, false, true);
+      } else {
+        scene.addEnemyModifier(modifier, true, true);
+      }
     }
   });
 }

src/test/abilities/beast_boost.test.ts

@@ -0,0 +1,97 @@
+import { Stat } from "#enums/stat";
+import GameManager from "#test/utils/gameManager";
+import { getMovePosition } from "#test/utils/gameManagerUtils";
+import { Abilities } from "#enums/abilities";
+import { Moves } from "#enums/moves";
+import { Species } from "#enums/species";
+import Phaser from "phaser";
+import { afterEach, beforeAll, beforeEach, describe, expect, it, vi } from "vitest";
+import { SPLASH_ONLY } from "../utils/testUtils";
+import { EnemyCommandPhase } from "#app/phases/enemy-command-phase.js";
+import { VictoryPhase } from "#app/phases/victory-phase";
+import { TurnStartPhase } from "#app/phases/turn-start-phase";
+import { BattlerIndex } from "#app/battle";
+
+describe("Abilities - Beast Boost", () => {
+  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.battleType("single");
+    game.override.enemySpecies(Species.BULBASAUR);
+    game.override.enemyAbility(Abilities.BEAST_BOOST);
+    game.override.ability(Abilities.BEAST_BOOST);
+    game.override.startingLevel(2000);
+    game.override.moveset([ Moves.FLAMETHROWER ]);
+    game.override.enemyMoveset(SPLASH_ONLY);
+  });
+
+  // Note that both MOXIE and BEAST_BOOST test for their current implementation and not the mainline behavior.
+  it("should prefer highest stat to boost its corresponding stat stage by 1 when winning a battle", async() => {
+    // SLOWBRO's highest stat is DEF, so it should be picked here
+    await game.startBattle([
+      Species.SLOWBRO
+    ]);
+
+    const playerPokemon = game.scene.getPlayerPokemon()!;
+
+    expect(playerPokemon.getStatStage(Stat.DEF)).toBe(0);
+
+    game.doAttack(getMovePosition(game.scene, 0, Moves.FLAMETHROWER));
+    await game.phaseInterceptor.runFrom(EnemyCommandPhase).to(VictoryPhase);
+
+    expect(playerPokemon.getStatStage(Stat.DEF)).toBe(1);
+  }, 20000);
+
+  it("should use in-battle overriden stats when determining the stat stage to raise by 1", async() => {
+    // If the opponent can GUARD_SPLIT, SLOWBRO's second highest stat should be SPATK
+    game.override.enemyMoveset(new Array(4).fill(Moves.GUARD_SPLIT));
+
+    await game.startBattle([
+      Species.SLOWBRO
+    ]);
+
+    const playerPokemon = game.scene.getPlayerPokemon()!;
+
+    expect(playerPokemon.getStatStage(Stat.SPATK)).toBe(0);
+
+    game.doAttack(getMovePosition(game.scene, 0, Moves.FLAMETHROWER));
+
+    await game.setTurnOrder([ BattlerIndex.ENEMY, BattlerIndex.PLAYER ]);
+
+    await game.phaseInterceptor.runFrom(TurnStartPhase).to(VictoryPhase);
+
+    expect(playerPokemon.getStatStage(Stat.SPATK)).toBe(1);
+  }, 20000);
+
+  it("should have order preference in case of stat ties", async() => {
+    // Order preference follows the order of EFFECTIVE_STAT
+    await game.startBattle([
+      Species.SLOWBRO
+    ]);
+
+    const playerPokemon = game.scene.getPlayerPokemon()!;
+
+    // Set up tie between SPATK, SPDEF, and SPD, where SPATK should win
+    vi.spyOn(playerPokemon, "stats", "get").mockReturnValue([ 10000, 1, 1, 100, 100, 100 ]);
+
+    expect(playerPokemon.getStatStage(Stat.SPATK)).toBe(0);
+
+    game.doAttack(getMovePosition(game.scene, 0, Moves.FLAMETHROWER));
+
+    await game.phaseInterceptor.runFrom(EnemyCommandPhase).to(VictoryPhase);
+
+    expect(playerPokemon.getStatStage(Stat.SPATK)).toBe(1);
+  }, 20000);
+});

src/test/abilities/imposter.test.ts

@@ -0,0 +1,99 @@
+import { afterEach, beforeAll, beforeEach, describe, expect, it } from "vitest";
+import Phaser from "phaser";
+import GameManager from "#app/test/utils/gameManager";
+import { Species } from "#enums/species";
+import { TurnEndPhase } from "#app/phases/turn-end-phase";
+import { Moves } from "#enums/moves";
+import { Stat, BATTLE_STATS, EFFECTIVE_STATS } from "#enums/stat";
+import { getMovePosition } from "#app/test/utils/gameManagerUtils";
+import { Abilities } from "#enums/abilities";
+import { SPLASH_ONLY } from "../utils/testUtils";
+
+describe("Abilities - Imposter", () => {
+  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.battleType("single");
+    game.override.enemySpecies(Species.MEW);
+    game.override.enemyLevel(200);
+    game.override.enemyAbility(Abilities.BEAST_BOOST);
+    game.override.enemyMoveset(SPLASH_ONLY);
+    game.override.ability(Abilities.IMPOSTER);
+    game.override.moveset([ Moves.TACKLE ]);
+  });
+
+  it("should copy species, ability, gender, all stats except HP, all stat stages, moveset, and types of target", async () => {
+    await game.startBattle([
+      Species.DITTO
+    ]);
+
+    game.doAttack(getMovePosition(game.scene, 0, Moves.TACKLE));
+    await game.phaseInterceptor.to(TurnEndPhase);
+
+    const player = game.scene.getPlayerPokemon()!;
+    const enemy = game.scene.getEnemyPokemon()!;
+
+    expect(player.getSpeciesForm().speciesId).toBe(enemy.getSpeciesForm().speciesId);
+    expect(player.getAbility()).toBe(enemy.getAbility());
+    expect(player.getGender()).toBe(enemy.getGender());
+
+    expect(player.getStat(Stat.HP, false)).not.toBe(enemy.getStat(Stat.HP));
+    for (const s of EFFECTIVE_STATS) {
+      expect(player.getStat(s, false)).toBe(enemy.getStat(s, false));
+    }
+
+    for (const s of BATTLE_STATS) {
+      expect(player.getStatStage(s)).toBe(enemy.getStatStage(s));
+    }
+
+    const playerMoveset = player.getMoveset();
+    const enemyMoveset = player.getMoveset();
+
+    for (let i = 0; i < playerMoveset.length && i < enemyMoveset.length; i++) {
+      // TODO: Checks for 5 PP should be done here when that gets addressed
+      expect(playerMoveset[i]?.moveId).toBe(enemyMoveset[i]?.moveId);
+    }
+
+    const playerTypes = player.getTypes();
+    const enemyTypes = enemy.getTypes();
+
+    for (let i = 0; i < playerTypes.length && i < enemyTypes.length; i++) {
+      expect(playerTypes[i]).toBe(enemyTypes[i]);
+    }
+  }, 20000);
+
+  it("should copy in-battle overridden stats", async () => {
+    game.override.enemyMoveset(new Array(4).fill(Moves.POWER_SPLIT));
+
+    await game.startBattle([
+      Species.DITTO
+    ]);
+
+    const player = game.scene.getPlayerPokemon()!;
+    const enemy = game.scene.getEnemyPokemon()!;
+
+    const avgAtk = Math.floor((player.getStat(Stat.ATK, false) + enemy.getStat(Stat.ATK, false)) / 2);
+    const avgSpAtk = Math.floor((player.getStat(Stat.SPATK, false) + enemy.getStat(Stat.SPATK, false)) / 2);
+
+    game.doAttack(getMovePosition(game.scene, 0, Moves.TACKLE));
+    await game.phaseInterceptor.to(TurnEndPhase);
+
+    expect(player.getStat(Stat.ATK, false)).toBe(avgAtk);
+    expect(enemy.getStat(Stat.ATK, false)).toBe(avgAtk);
+
+    expect(player.getStat(Stat.SPATK, false)).toBe(avgSpAtk);
+    expect(enemy.getStat(Stat.SPATK, false)).toBe(avgSpAtk);
+  });
+});

src/test/abilities/moxie.test.ts

@@ -38,7 +38,7 @@ describe("Abilities - Moxie", () => {
     game.override.enemyMoveset(SPLASH_ONLY);
   });
 
-  it("should raise ATK stat stage by 1 when defeating an enemy Pokemon", async() => {
+  it("should raise ATK stat stage by 1 when winning a battle", async() => {
     const moveToUse = Moves.AERIAL_ACE;
     await game.startBattle([
       Species.MIGHTYENA,

src/test/items/temp_stat_stage_booster.test.ts

@@ -0,0 +1,136 @@
+import { Stat } from "#enums/stat";
+import GameManager from "#test/utils/gameManager";
+import { Species } from "#enums/species";
+import Phase from "phaser";
+import { afterEach, beforeAll, beforeEach, describe, expect, it, vi } from "vitest";
+import { Moves } from "#app/enums/moves.js";
+import { getMovePosition } from "../utils/gameManagerUtils";
+import { TurnEndPhase } from "#app/phases/turn-end-phase.js";
+import { SPLASH_ONLY } from "../utils/testUtils";
+import { Abilities } from "#app/enums/abilities.js";
+import Overrides from "#app/overrides";
+import { TempStatStageBoosterModifier } from "#app/modifier/modifier.js";
+import { Mode } from "#app/ui/ui.js";
+import { Button } from "#app/enums/buttons.js";
+import { CommandPhase } from "#app/phases/command-phase.js";
+import { NewBattlePhase } from "#app/phases/new-battle-phase.js";
+import ModifierSelectUiHandler from "#app/ui/modifier-select-ui-handler.js";
+import { TurnInitPhase } from "#app/phases/turn-init-phase.js";
+import { BattleEndPhase } from "#app/phases/battle-end-phase.js";
+import { EnemyCommandPhase } from "#app/phases/enemy-command-phase.js";
+
+
+describe("Items - Temporary Stat Stage Boosters", () => {
+  let phaserGame: Phaser.Game;
+  let game: GameManager;
+
+  beforeAll(() => {
+    phaserGame = new Phase.Game({
+      type: Phaser.HEADLESS,
+    });
+  });
+
+  afterEach(() => {
+    game.phaseInterceptor.restoreOg();
+  });
+
+  beforeEach(() => {
+    game = new GameManager(phaserGame);
+
+    game.override.battleType("single");
+    game.override.enemySpecies(Species.MEW);
+    game.override.enemyMoveset(SPLASH_ONLY);
+    game.override.enemyAbility(Abilities.PICKUP);
+    game.override.moveset([ Moves.TACKLE, Moves.HONE_CLAWS, Moves.BELLY_DRUM ]);
+    game.override.startingModifier([{ name: "TEMP_STAT_STAGE_BOOSTER", type: Stat.ATK }]);
+  });
+
+  it("should provide a x1.3 stat stage multiplier alone", async() => {
+    await game.startBattle([
+      Species.PIKACHU
+    ]);
+
+    const partyMember = game.scene.getPlayerPokemon()!;
+
+    vi.spyOn(partyMember, "getStatStageMultiplier");
+
+    game.doAttack(getMovePosition(game.scene, 0, Moves.TACKLE));
+
+    await game.phaseInterceptor.runFrom(EnemyCommandPhase).to(TurnEndPhase);
+
+    expect(partyMember.getStatStageMultiplier).toHaveReturnedWith(1.3);
+  }, 20000);
+
+  it("should only increase existing stat stage multiplier by 0.3", async() => {
+    await game.startBattle([
+      Species.PIKACHU
+    ]);
+
+    const partyMember = game.scene.getPlayerPokemon()!;
+
+    vi.spyOn(partyMember, "getStatStageMultiplier");
+
+    game.doAttack(getMovePosition(game.scene, 0, Moves.HONE_CLAWS));
+
+    await game.phaseInterceptor.to(TurnEndPhase);
+
+    game.doAttack(getMovePosition(game.scene, 0, Moves.TACKLE));
+
+    await game.phaseInterceptor.to(TurnEndPhase);
+
+    expect(partyMember.getStatStageMultiplier).toHaveReturnedWith(1.8);
+  }, 20000);
+
+  it("should not increase past x4 maximum stat stage multiplier", async() => {
+    await game.startBattle([
+      Species.PIKACHU
+    ]);
+
+    const partyMember = game.scene.getPlayerPokemon()!;
+
+    vi.spyOn(partyMember, "getStatStageMultiplier");
+
+    game.doAttack(getMovePosition(game.scene, 0, Moves.BELLY_DRUM));
+
+    await game.phaseInterceptor.to(TurnEndPhase);
+
+    game.doAttack(getMovePosition(game.scene, 0, Moves.TACKLE));
+
+    await game.phaseInterceptor.to(TurnEndPhase);
+
+    expect(partyMember.getStatStageMultiplier).toHaveReturnedWith(4);
+  }, 20000);
+
+  it("should renew how many battles are left of existing booster when picking up new booster of same type", async() => {
+    game.override.startingLevel(200);
+    vi.spyOn(Overrides, "ITEM_REWARD_OVERRIDE", "get").mockReturnValue([{ name: "TEMP_STAT_STAGE_BOOSTER", type: Stat.ATK }]);
+    await game.startBattle([
+      Species.PIKACHU
+    ]);
+
+    game.doAttack(getMovePosition(game.scene, 0, Moves.TACKLE));
+
+    await game.phaseInterceptor.to(BattleEndPhase);
+
+    const modifier = game.scene.findModifier(m => m instanceof TempStatStageBoosterModifier) as TempStatStageBoosterModifier;
+    expect(modifier.getBattlesLeft()).toBe(4);
+
+    // Forced X Attack to spawn in the first slot with override
+    game.onNextPrompt("SelectModifierPhase", Mode.MODIFIER_SELECT, () => {
+      const handler = game.scene.ui.getHandler() as ModifierSelectUiHandler;
+      handler.processInput(Button.ACTION);
+    }, () => game.isCurrentPhase(CommandPhase) || game.isCurrentPhase(NewBattlePhase), true);
+
+    await game.phaseInterceptor.to(TurnInitPhase);
+
+    // Making sure only one booster is in the modifier list even after picking up another
+    let count = 0;
+    for (const m of game.scene.modifiers) {
+      if (m instanceof TempStatStageBoosterModifier) {
+        count++;
+        expect((m as TempStatStageBoosterModifier).getBattlesLeft()).toBe(5);
+      }
+    }
+    expect(count).toBe(1);
+  }, 20000);
+});

src/test/moves/guard_split.test.ts

@@ -0,0 +1,83 @@
+import { afterEach, beforeAll, beforeEach, describe, expect, it, vi } from "vitest";
+import Phaser from "phaser";
+import GameManager from "#app/test/utils/gameManager";
+import Overrides from "#app/overrides";
+import { Species } from "#enums/species";
+import { TurnEndPhase } from "#app/phases/turn-end-phase";
+import { Moves } from "#enums/moves";
+import { Stat } from "#enums/stat";
+import { getMovePosition } from "#app/test/utils/gameManagerUtils";
+import { Abilities } from "#enums/abilities";
+import { SPLASH_ONLY } from "../utils/testUtils";
+
+describe("Moves - Guard Split", () => {
+  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.battleType("single");
+    game.override.enemyAbility(Abilities.NONE);
+    game.override.enemySpecies(Species.MEW);
+    game.override.enemyLevel(200);
+    game.override.moveset([ Moves.GUARD_SPLIT ]);
+    game.override.ability(Abilities.NONE);
+  });
+
+  it("should average the user's Defense and Special Defense stats with those of the target", async () => {
+    vi.spyOn(Overrides, "OPP_MOVESET_OVERRIDE", "get").mockReturnValue(SPLASH_ONLY);
+    await game.startBattle([
+      Species.INDEEDEE
+    ]);
+
+    const player = game.scene.getPlayerPokemon()!;
+    const enemy = game.scene.getEnemyPokemon()!;
+
+    const avgDef = Math.floor((player.getStat(Stat.DEF, false) + enemy.getStat(Stat.DEF, false)) / 2);
+    const avgSpDef = Math.floor((player.getStat(Stat.SPDEF, false) + enemy.getStat(Stat.SPDEF, false)) / 2);
+
+    game.doAttack(getMovePosition(game.scene, 0, Moves.GUARD_SPLIT));
+    await game.phaseInterceptor.to(TurnEndPhase);
+
+    expect(player.getStat(Stat.DEF, false)).toBe(avgDef);
+    expect(enemy.getStat(Stat.DEF, false)).toBe(avgDef);
+
+    expect(player.getStat(Stat.SPDEF, false)).toBe(avgSpDef);
+    expect(enemy.getStat(Stat.SPDEF, false)).toBe(avgSpDef);
+  }, 20000);
+
+  it("should be idempotent", async () => {
+    vi.spyOn(Overrides, "OPP_MOVESET_OVERRIDE", "get").mockReturnValue([ Moves.GUARD_SPLIT, Moves.GUARD_SPLIT, Moves.GUARD_SPLIT, Moves.GUARD_SPLIT ]);
+    await game.startBattle([
+      Species.INDEEDEE
+    ]);
+
+    const player = game.scene.getPlayerPokemon()!;
+    const enemy = game.scene.getEnemyPokemon()!;
+
+    const avgDef = Math.floor((player.getStat(Stat.DEF, false) + enemy.getStat(Stat.DEF, false)) / 2);
+    const avgSpDef = Math.floor((player.getStat(Stat.SPDEF, false) + enemy.getStat(Stat.SPDEF, false)) / 2);
+
+    game.doAttack(getMovePosition(game.scene, 0, Moves.GUARD_SPLIT));
+    await game.phaseInterceptor.to(TurnEndPhase);
+
+    game.doAttack(getMovePosition(game.scene, 0, Moves.GUARD_SPLIT));
+    await game.phaseInterceptor.to(TurnEndPhase);
+
+    expect(player.getStat(Stat.DEF, false)).toBe(avgDef);
+    expect(enemy.getStat(Stat.DEF, false)).toBe(avgDef);
+
+    expect(player.getStat(Stat.SPDEF, false)).toBe(avgSpDef);
+    expect(enemy.getStat(Stat.SPDEF, false)).toBe(avgSpDef);
+  }, 20000);
+});

src/test/moves/power_split.test.ts

@@ -0,0 +1,83 @@
+import { afterEach, beforeAll, beforeEach, describe, expect, it, vi } from "vitest";
+import Phaser from "phaser";
+import GameManager from "#app/test/utils/gameManager";
+import Overrides from "#app/overrides";
+import { Species } from "#enums/species";
+import { TurnEndPhase } from "#app/phases/turn-end-phase";
+import { Moves } from "#enums/moves";
+import { Stat } from "#enums/stat";
+import { getMovePosition } from "#app/test/utils/gameManagerUtils";
+import { Abilities } from "#enums/abilities";
+import { SPLASH_ONLY } from "../utils/testUtils";
+
+describe("Moves - Power Split", () => {
+  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.battleType("single");
+    game.override.enemyAbility(Abilities.NONE);
+    game.override.enemySpecies(Species.MEW);
+    game.override.enemyLevel(200);
+    game.override.moveset([ Moves.POWER_SPLIT ]);
+    game.override.ability(Abilities.NONE);
+  });
+
+  it("should average the user's Attack and Special Attack stats with those of the target", async () => {
+    vi.spyOn(Overrides, "OPP_MOVESET_OVERRIDE", "get").mockReturnValue(SPLASH_ONLY);
+    await game.startBattle([
+      Species.INDEEDEE
+    ]);
+
+    const player = game.scene.getPlayerPokemon()!;
+    const enemy = game.scene.getEnemyPokemon()!;
+
+    const avgAtk = Math.floor((player.getStat(Stat.ATK, false) + enemy.getStat(Stat.ATK, false)) / 2);
+    const avgSpAtk = Math.floor((player.getStat(Stat.SPATK, false) + enemy.getStat(Stat.SPATK, false)) / 2);
+
+    game.doAttack(getMovePosition(game.scene, 0, Moves.POWER_SPLIT));
+    await game.phaseInterceptor.to(TurnEndPhase);
+
+    expect(player.getStat(Stat.ATK, false)).toBe(avgAtk);
+    expect(enemy.getStat(Stat.ATK, false)).toBe(avgAtk);
+
+    expect(player.getStat(Stat.SPATK, false)).toBe(avgSpAtk);
+    expect(enemy.getStat(Stat.SPATK, false)).toBe(avgSpAtk);
+  }, 20000);
+
+  it("should be idempotent", async () => {
+    vi.spyOn(Overrides, "OPP_MOVESET_OVERRIDE", "get").mockReturnValue([ Moves.POWER_SPLIT, Moves.POWER_SPLIT, Moves.POWER_SPLIT, Moves.POWER_SPLIT ]);
+    await game.startBattle([
+      Species.INDEEDEE
+    ]);
+
+    const player = game.scene.getPlayerPokemon()!;
+    const enemy = game.scene.getEnemyPokemon()!;
+
+    const avgAtk = Math.floor((player.getStat(Stat.ATK, false) + enemy.getStat(Stat.ATK, false)) / 2);
+    const avgSpAtk = Math.floor((player.getStat(Stat.SPATK, false) + enemy.getStat(Stat.SPATK, false)) / 2);
+
+    game.doAttack(getMovePosition(game.scene, 0, Moves.POWER_SPLIT));
+    await game.phaseInterceptor.to(TurnEndPhase);
+
+    game.doAttack(getMovePosition(game.scene, 0, Moves.POWER_SPLIT));
+    await game.phaseInterceptor.to(TurnEndPhase);
+
+    expect(player.getStat(Stat.ATK, false)).toBe(avgAtk);
+    expect(enemy.getStat(Stat.ATK, false)).toBe(avgAtk);
+
+    expect(player.getStat(Stat.SPATK, false)).toBe(avgSpAtk);
+    expect(enemy.getStat(Stat.SPATK, false)).toBe(avgSpAtk);
+  }, 20000);
+});

src/test/moves/transform.test.ts

@@ -0,0 +1,99 @@
+import { afterEach, beforeAll, beforeEach, describe, expect, it } from "vitest";
+import Phaser from "phaser";
+import GameManager from "#app/test/utils/gameManager";
+import { Species } from "#enums/species";
+import { TurnEndPhase } from "#app/phases/turn-end-phase";
+import { Moves } from "#enums/moves";
+import { Stat, BATTLE_STATS, EFFECTIVE_STATS } from "#enums/stat";
+import { getMovePosition } from "#app/test/utils/gameManagerUtils";
+import { Abilities } from "#enums/abilities";
+import { SPLASH_ONLY } from "../utils/testUtils";
+
+describe("Moves - Transform", () => {
+  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.battleType("single");
+    game.override.enemySpecies(Species.MEW);
+    game.override.enemyLevel(200);
+    game.override.enemyAbility(Abilities.BEAST_BOOST);
+    game.override.enemyMoveset(SPLASH_ONLY);
+    game.override.ability(Abilities.INTIMIDATE);
+    game.override.moveset([ Moves.TRANSFORM ]);
+  });
+
+  it("should copy species, ability, gender, all stats except HP, all stat stages, moveset, and types of target", async () => {
+    await game.startBattle([
+      Species.DITTO
+    ]);
+
+    game.doAttack(getMovePosition(game.scene, 0, Moves.TRANSFORM));
+    await game.phaseInterceptor.to(TurnEndPhase);
+
+    const player = game.scene.getPlayerPokemon()!;
+    const enemy = game.scene.getEnemyPokemon()!;
+
+    expect(player.getSpeciesForm().speciesId).toBe(enemy.getSpeciesForm().speciesId);
+    expect(player.getAbility()).toBe(enemy.getAbility());
+    expect(player.getGender()).toBe(enemy.getGender());
+
+    expect(player.getStat(Stat.HP, false)).not.toBe(enemy.getStat(Stat.HP));
+    for (const s of EFFECTIVE_STATS) {
+      expect(player.getStat(s, false)).toBe(enemy.getStat(s, false));
+    }
+
+    for (const s of BATTLE_STATS) {
+      expect(player.getStatStage(s)).toBe(enemy.getStatStage(s));
+    }
+
+    const playerMoveset = player.getMoveset();
+    const enemyMoveset = player.getMoveset();
+
+    for (let i = 0; i < playerMoveset.length && i < enemyMoveset.length; i++) {
+      // TODO: Checks for 5 PP should be done here when that gets addressed
+      expect(playerMoveset[i]?.moveId).toBe(enemyMoveset[i]?.moveId);
+    }
+
+    const playerTypes = player.getTypes();
+    const enemyTypes = enemy.getTypes();
+
+    for (let i = 0; i < playerTypes.length && i < enemyTypes.length; i++) {
+      expect(playerTypes[i]).toBe(enemyTypes[i]);
+    }
+  }, 20000);
+
+  it("should copy in-battle overridden stats", async () => {
+    game.override.enemyMoveset(new Array(4).fill(Moves.POWER_SPLIT));
+
+    await game.startBattle([
+      Species.DITTO
+    ]);
+
+    const player = game.scene.getPlayerPokemon()!;
+    const enemy = game.scene.getEnemyPokemon()!;
+
+    const avgAtk = Math.floor((player.getStat(Stat.ATK, false) + enemy.getStat(Stat.ATK, false)) / 2);
+    const avgSpAtk = Math.floor((player.getStat(Stat.SPATK, false) + enemy.getStat(Stat.SPATK, false)) / 2);
+
+    game.doAttack(getMovePosition(game.scene, 0, Moves.TRANSFORM));
+    await game.phaseInterceptor.to(TurnEndPhase);
+
+    expect(player.getStat(Stat.ATK, false)).toBe(avgAtk);
+    expect(enemy.getStat(Stat.ATK, false)).toBe(avgAtk);
+
+    expect(player.getStat(Stat.SPATK, false)).toBe(avgSpAtk);
+    expect(enemy.getStat(Stat.SPATK, false)).toBe(avgSpAtk);
+  });
+});