[Test] Update test utils (#5848)

* [Test] Add/update test utils

- Add `FieldHelper` which has methods to mock a pokemon's ability
or force a pokemon to be Terastallized

- Add `MoveHelper#use` which can be used to remove the need
for setting pokemon move overrides by modifying the
moveset of the pokemon

- Add `MoveHelper#selectEnemyMove` to make an enemy pokemon
select a specific move

- Add `MoveHelper#forceEnemyMove` which modifies
the pokemon's moveset and then uses `selectEnemyMove`

- Fix `GameManager#toNextTurn` to work correctly in double battles

- Add `GameManager#toEndOfTurn` which advances to the end of the turn

* Update some tests

- Disable broken Good As Gold test
and add `.edgeCase` to Good As Gold

- Fix Powder test

- Update some tests to demonstrate new methods

src/data/abilities/ability.ts

@@ -7425,7 +7425,12 @@ export function initAbilities() {
       .uncopiable()
       .attr(NoTransformAbilityAbAttr),
     new Ability(Abilities.GOOD_AS_GOLD, 9)
-      .attr(MoveImmunityAbAttr, (pokemon, attacker, move) => pokemon !== attacker && move.category === MoveCategory.STATUS && ![ MoveTarget.ENEMY_SIDE, MoveTarget.BOTH_SIDES, MoveTarget.USER_SIDE ].includes(move.moveTarget))
+      .attr(MoveImmunityAbAttr, (pokemon, attacker, move) =>
+        pokemon !== attacker
+        && move.category === MoveCategory.STATUS
+        && ![ MoveTarget.ENEMY_SIDE, MoveTarget.BOTH_SIDES, MoveTarget.USER_SIDE ].includes(move.moveTarget)
+      )
+      .edgeCase() // Heal Bell should not cure the status of a Pokemon with Good As Gold
       .ignorable(),
     new Ability(Abilities.VESSEL_OF_RUIN, 9)
       .attr(FieldMultiplyStatAbAttr, Stat.SPATK, 0.75)

test/abilities/good_as_gold.test.ts

@@ -1,6 +1,6 @@
 import { BattlerIndex } from "#app/battle";
-import { allAbilities } from "#app/data/data-lists";
 import { ArenaTagSide } from "#app/data/arena-tag";
+import { allAbilities } from "#app/data/data-lists";
 import { ArenaTagType } from "#app/enums/arena-tag-type";
 import { BattlerTagType } from "#app/enums/battler-tag-type";
 import { Stat } from "#app/enums/stat";
@@ -107,35 +107,33 @@ describe("Abilities - Good As Gold", () => {
     expect(game.scene.getPlayerField()[1].getTag(BattlerTagType.HELPING_HAND)).toBeUndefined();
   });
 
-  it("should block the ally's heal bell, but only if the good as gold user is on the field", async () => {
-    game.override.battleStyle("double");
-    game.override.moveset([Moves.HEAL_BELL, Moves.SPLASH]);
-    game.override.statusEffect(StatusEffect.BURN);
-    await game.classicMode.startBattle([Species.MAGIKARP, Species.FEEBAS, Species.ABRA]);
-    const [good_as_gold, ball_fetch] = game.scene.getPlayerField();
-
-    // Force second pokemon to have ball fetch to isolate to a single mon.
-    vi.spyOn(ball_fetch, "getAbility").mockReturnValue(allAbilities[Abilities.BALL_FETCH]);
+  // TODO: re-enable when heal bell is fixed
+  it.todo("should block the ally's heal bell, but only if the good as gold user is on the field", async () => {
+    game.override.battleStyle("double").statusEffect(StatusEffect.BURN);
+    await game.classicMode.startBattle([Species.MILOTIC, Species.FEEBAS, Species.ABRA]);
+    const [milotic, feebas, abra] = game.scene.getPlayerParty();
+    game.field.mockAbility(milotic, Abilities.GOOD_AS_GOLD);
+    game.field.mockAbility(feebas, Abilities.BALL_FETCH);
+    game.field.mockAbility(abra, Abilities.BALL_FETCH);
 
     // turn 1
-    game.move.select(Moves.SPLASH, 0);
-    game.move.select(Moves.HEAL_BELL, 1);
+    game.move.use(Moves.SPLASH, 0);
+    game.move.use(Moves.HEAL_BELL, 1);
     await game.toNextTurn();
-    expect(good_as_gold.status?.effect).toBe(StatusEffect.BURN);
+    expect(milotic.status?.effect).toBe(StatusEffect.BURN);
 
     game.doSwitchPokemon(2);
-    game.move.select(Moves.HEAL_BELL, 0);
+    game.move.use(Moves.HEAL_BELL, 1);
     await game.toNextTurn();
-    expect(good_as_gold.status?.effect).toBeUndefined();
+    expect(milotic.status?.effect).toBeUndefined();
   });
 
   it("should not block field targeted effects like rain dance", async () => {
     game.override.battleStyle("single");
     game.override.enemyMoveset([Moves.RAIN_DANCE]);
-    game.override.weather(WeatherType.NONE);
     await game.classicMode.startBattle([Species.MAGIKARP]);
 
-    game.move.select(Moves.SPLASH, 0);
+    game.move.use(Moves.SPLASH, 0);
     await game.phaseInterceptor.to("BerryPhase");
 
     expect(game.scene.arena.weather?.weatherType).toBe(WeatherType.RAIN);

test/moves/alluring_voice.test.ts

@@ -29,20 +29,18 @@ describe("Moves - Alluring Voice", () => {
       .disableCrits()
       .enemySpecies(Species.MAGIKARP)
       .enemyAbility(Abilities.ICE_SCALES)
-      .enemyMoveset([Moves.HOWL])
+      .enemyMoveset(Moves.HOWL)
       .startingLevel(10)
       .enemyLevel(10)
-      .starterSpecies(Species.FEEBAS)
-      .ability(Abilities.BALL_FETCH)
-      .moveset([Moves.ALLURING_VOICE]);
+      .ability(Abilities.BALL_FETCH);
   });
 
   it("should confuse the opponent if their stat stages were raised", async () => {
-    await game.classicMode.startBattle();
+    await game.classicMode.startBattle([Species.FEEBAS]);
 
     const enemy = game.scene.getEnemyPokemon()!;
 
-    game.move.select(Moves.ALLURING_VOICE);
+    game.move.use(Moves.ALLURING_VOICE);
     await game.setTurnOrder([BattlerIndex.ENEMY, BattlerIndex.PLAYER]);
     await game.phaseInterceptor.to(BerryPhase);
 

test/moves/chloroblast.test.ts

@@ -1,3 +1,4 @@
+import { MoveResult } from "#app/field/pokemon";
 import { Abilities } from "#enums/abilities";
 import { Moves } from "#enums/moves";
 import { Species } from "#enums/species";
@@ -22,21 +23,23 @@ describe("Moves - Chloroblast", () => {
   beforeEach(() => {
     game = new GameManager(phaserGame);
     game.override
-      .moveset([Moves.CHLOROBLAST])
       .ability(Abilities.BALL_FETCH)
       .battleStyle("single")
       .disableCrits()
       .enemySpecies(Species.MAGIKARP)
-      .enemyAbility(Abilities.BALL_FETCH)
-      .enemyMoveset(Moves.PROTECT);
+      .enemyAbility(Abilities.BALL_FETCH);
   });
 
   it("should not deal recoil damage if the opponent uses protect", async () => {
     await game.classicMode.startBattle([Species.FEEBAS]);
 
-    game.move.select(Moves.CHLOROBLAST);
-    await game.phaseInterceptor.to("BerryPhase");
+    game.move.use(Moves.CHLOROBLAST);
+    await game.move.forceEnemyMove(Moves.PROTECT);
+    await game.toEndOfTurn();
 
-    expect(game.scene.getPlayerPokemon()!.isFullHp()).toBe(true);
+    const player = game.field.getPlayerPokemon();
+
+    expect(player.isFullHp()).toBe(true);
+    expect(player.getLastXMoves()[0]).toMatchObject({ result: MoveResult.MISS, move: Moves.CHLOROBLAST });
   });
 });

test/moves/powder.test.ts

@@ -1,15 +1,15 @@
-import { afterEach, beforeAll, beforeEach, describe, expect, it } from "vitest";
-import Phaser from "phaser";
-import GameManager from "#test/testUtils/gameManager";
+import { BattlerIndex } from "#app/battle";
+import { MoveResult, PokemonMove } from "#app/field/pokemon";
+import { BerryPhase } from "#app/phases/berry-phase";
+import { MoveEffectPhase } from "#app/phases/move-effect-phase";
 import { Abilities } from "#enums/abilities";
 import { Moves } from "#enums/moves";
-import { Species } from "#enums/species";
-import { BerryPhase } from "#app/phases/berry-phase";
-import { MoveResult, PokemonMove } from "#app/field/pokemon";
 import { PokemonType } from "#enums/pokemon-type";
-import { MoveEffectPhase } from "#app/phases/move-effect-phase";
+import { Species } from "#enums/species";
 import { StatusEffect } from "#enums/status-effect";
-import { BattlerIndex } from "#app/battle";
+import GameManager from "#test/testUtils/gameManager";
+import Phaser from "phaser";
+import { afterEach, beforeAll, beforeEach, describe, expect, it } from "vitest";
 
 describe("Moves - Powder", () => {
   let phaserGame: Phaser.Game;
@@ -161,7 +161,6 @@ describe("Moves - Powder", () => {
     game.move.select(Moves.ROAR, 0, BattlerIndex.ENEMY_2);
     game.move.select(Moves.SPLASH, 1);
     await game.toNextTurn();
-    await game.toNextTurn(); // Requires game.toNextTurn() twice due to double battle
 
     // Turn 2: Enemy should activate Powder twice: From using Ember, and from copying Fiery Dance via Dancer
     playerPokemon.hp = playerPokemon.getMaxHp();

test/testUtils/gameManager.ts

@@ -5,6 +5,7 @@ import { getMoveTargets } from "#app/data/moves/move";
 import type { EnemyPokemon, PlayerPokemon } from "#app/field/pokemon";
 import Trainer from "#app/field/trainer";
 import { GameModes, getGameMode } from "#app/game-mode";
+import { globalScene } from "#app/global-scene";
 import { ModifierTypeOption, modifierTypes } from "#app/modifier/modifier-type";
 import overrides from "#app/overrides";
 import { CheckSwitchPhase } from "#app/phases/check-switch-phase";
@@ -22,15 +23,13 @@ import { TitlePhase } from "#app/phases/title-phase";
 import { TurnEndPhase } from "#app/phases/turn-end-phase";
 import { TurnInitPhase } from "#app/phases/turn-init-phase";
 import { TurnStartPhase } from "#app/phases/turn-start-phase";
-import ErrorInterceptor from "#test/testUtils/errorInterceptor";
-import type InputsHandler from "#test/testUtils/inputsHandler";
 import type BallUiHandler from "#app/ui/ball-ui-handler";
 import type BattleMessageUiHandler from "#app/ui/battle-message-ui-handler";
 import type CommandUiHandler from "#app/ui/command-ui-handler";
 import type ModifierSelectUiHandler from "#app/ui/modifier-select-ui-handler";
 import type PartyUiHandler from "#app/ui/party-ui-handler";
+import type StarterSelectUiHandler from "#app/ui/starter-select-ui-handler";
 import type TargetSelectUiHandler from "#app/ui/target-select-ui-handler";
-import { UiMode } from "#enums/ui-mode";
 import { isNullOrUndefined } from "#app/utils/common";
 import { BattleStyle } from "#enums/battle-style";
 import { Button } from "#enums/buttons";
@@ -40,24 +39,26 @@ import type { Moves } from "#enums/moves";
 import type { MysteryEncounterType } from "#enums/mystery-encounter-type";
 import { PlayerGender } from "#enums/player-gender";
 import type { Species } from "#enums/species";
+import { UiMode } from "#enums/ui-mode";
+import ErrorInterceptor from "#test/testUtils/errorInterceptor";
 import { generateStarter, waitUntil } from "#test/testUtils/gameManagerUtils";
 import GameWrapper from "#test/testUtils/gameWrapper";
 import { ChallengeModeHelper } from "#test/testUtils/helpers/challengeModeHelper";
 import { ClassicModeHelper } from "#test/testUtils/helpers/classicModeHelper";
 import { DailyModeHelper } from "#test/testUtils/helpers/dailyModeHelper";
+import { FieldHelper } from "#test/testUtils/helpers/field-helper";
 import { ModifierHelper } from "#test/testUtils/helpers/modifiersHelper";
 import { MoveHelper } from "#test/testUtils/helpers/moveHelper";
 import { OverridesHelper } from "#test/testUtils/helpers/overridesHelper";
 import { ReloadHelper } from "#test/testUtils/helpers/reloadHelper";
 import { SettingsHelper } from "#test/testUtils/helpers/settingsHelper";
+import type InputsHandler from "#test/testUtils/inputsHandler";
+import { MockFetch } from "#test/testUtils/mocks/mockFetch";
 import PhaseInterceptor from "#test/testUtils/phaseInterceptor";
 import TextInterceptor from "#test/testUtils/TextInterceptor";
 import { AES, enc } from "crypto-js";
 import fs from "node:fs";
 import { expect, vi } from "vitest";
-import { globalScene } from "#app/global-scene";
-import type StarterSelectUiHandler from "#app/ui/starter-select-ui-handler";
-import { MockFetch } from "#test/testUtils/mocks/mockFetch";
 
 /**
  * Class to manage the game state and transitions between phases.
@@ -76,6 +77,7 @@ export default class GameManager {
   public readonly settings: SettingsHelper;
   public readonly reload: ReloadHelper;
   public readonly modifiers: ModifierHelper;
+  public readonly field: FieldHelper;
 
   /**
    * Creates an instance of GameManager.
@@ -123,6 +125,7 @@ export default class GameManager {
     this.settings = new SettingsHelper(this);
     this.reload = new ReloadHelper(this);
     this.modifiers = new ModifierHelper(this);
+    this.field = new FieldHelper(this);
     this.override.sanitizeOverrides();
 
     // Disables Mystery Encounters on all tests (can be overridden at test level)
@@ -383,6 +386,7 @@ export default class GameManager {
    * @param moveId - The {@linkcode Moves | move} the enemy will use
    * @param target - The {@linkcode BattlerIndex} of the target against which the enemy will use the given move;
    * will use normal target selection priorities if omitted.
+   * @deprecated Use {@linkcode MoveHelper.forceEnemyMove} or {@linkcode MoveHelper.selectEnemyMove}
    */
   async forceEnemyMove(moveId: Moves, target?: BattlerIndex) {
     // Wait for the next EnemyCommandPhase to start
@@ -417,9 +421,15 @@ export default class GameManager {
     };
   }
 
-  /** Transition to the next upcoming {@linkcode CommandPhase} */
+  /** Transition to the first {@linkcode CommandPhase} of the next turn. */
   async toNextTurn() {
-    await this.phaseInterceptor.to(CommandPhase);
+    await this.phaseInterceptor.to("TurnInitPhase");
+    await this.phaseInterceptor.to("CommandPhase");
+  }
+
+  /** Transition to the {@linkcode TurnEndPhase | end of the current turn}. */
+  async toEndOfTurn() {
+    await this.phaseInterceptor.to("TurnEndPhase");
   }
 
   /**
@@ -541,8 +551,8 @@ export default class GameManager {
   }
 
   /**
-   * Select a pokemon from the party menu during the given phase. 
-   * Only really handles the basic case of "navigate to party slot and press Action twice" - 
+   * Select a pokemon from the party menu during the given phase.
+   * Only really handles the basic case of "navigate to party slot and press Action twice" -
    * any menus that come up afterwards are ignored and must be handled separately by the caller.
    * @param slot - The 0-indexed position of the pokemon in your party to switch to
    * @param inPhase - Which phase to expect the selection to occur in. Defaults to `SwitchPhase`

test/testUtils/helpers/field-helper.ts

@@ -0,0 +1,87 @@
+// -- start tsdoc imports --
+// biome-ignore lint/correctness/noUnusedImports: TSDoc import
+import type { globalScene } from "#app/global-scene";
+// -- end tsdoc imports --
+
+import type { BattlerIndex } from "#app/battle";
+import type { Ability } from "#app/data/abilities/ability-class";
+import { allAbilities } from "#app/data/data-lists";
+import type Pokemon from "#app/field/pokemon";
+import type { EnemyPokemon, PlayerPokemon } from "#app/field/pokemon";
+import type { Abilities } from "#enums/abilities";
+import type { PokemonType } from "#enums/pokemon-type";
+import { Stat } from "#enums/stat";
+import { GameManagerHelper } from "#test/testUtils/helpers/gameManagerHelper";
+import { expect, type MockInstance, vi } from "vitest";
+
+/** Helper to manage pokemon */
+export class FieldHelper extends GameManagerHelper {
+  /**
+   * Passthrough for {@linkcode globalScene.getPlayerPokemon} that adds an `undefined` check for
+   * the Pokemon so that the return type for the function doesn't have `undefined`.
+   * This removes the need to add a `!` like when calling `game.scene.getPlayerPokemon()!`.
+   * @param includeSwitching Whether a pokemon that is currently switching out is valid, default `true`
+   * @returns The first {@linkcode PlayerPokemon} that is {@linkcode globalScene.getPlayerField on the field}
+   * and {@linkcode PlayerPokemon.isActive is active}
+   * (aka {@linkcode PlayerPokemon.isAllowedInBattle is allowed in battle}).
+   */
+  public getPlayerPokemon(includeSwitching = true): PlayerPokemon {
+    const pokemon = this.game.scene.getPlayerPokemon(includeSwitching);
+    expect(pokemon).toBeDefined();
+    return pokemon!;
+  }
+
+  /**
+   * Passthrough for {@linkcode globalScene.getEnemyPokemon} that adds an `undefined` check for
+   * the Pokemon so that the return type for the function doesn't have `undefined`.
+   * This removes the need to add a `!` like when calling `game.scene.getEnemyPokemon()!`.
+   * @param includeSwitching Whether a pokemon that is currently switching out is valid, default `true`
+   * @returns The first {@linkcode EnemyPokemon} that is {@linkcode globalScene.getEnemyField on the field}
+   * and {@linkcode EnemyPokemon.isActive is active}
+   * (aka {@linkcode EnemyPokemon.isAllowedInBattle is allowed in battle}).
+   */
+  public getEnemyPokemon(includeSwitching = true): EnemyPokemon {
+    const pokemon = this.game.scene.getEnemyPokemon(includeSwitching);
+    expect(pokemon).toBeDefined();
+    return pokemon!;
+  }
+
+  /**
+   * @returns The {@linkcode BattlerIndex | indexes} of Pokemon on the field in order of decreasing Speed.
+   * Speed ties are returned in increasing order of index.
+   *
+   * Note: Trick Room does not modify the speed of Pokemon on the field.
+   */
+  public getSpeedOrder(): BattlerIndex[] {
+    return this.game.scene
+      .getField(true)
+      .sort((pA, pB) => pB.getEffectiveStat(Stat.SPD) - pA.getEffectiveStat(Stat.SPD))
+      .map(p => p.getBattlerIndex());
+  }
+
+  /**
+   * Mocks a pokemon's ability, overriding its existing ability (takes precedence over global overrides)
+   * @param pokemon - The pokemon to mock the ability of
+   * @param ability - The ability to be mocked
+   * @returns A {@linkcode MockInstance} object
+   * @see {@linkcode vi.spyOn}
+   * @see https://vitest.dev/api/mock#mockreturnvalue
+   */
+  public mockAbility(pokemon: Pokemon, ability: Abilities): MockInstance<(baseOnly?: boolean) => Ability> {
+    return vi.spyOn(pokemon, "getAbility").mockReturnValue(allAbilities[ability]);
+  }
+
+  /**
+   * Forces a pokemon to be terastallized. Defaults to the pokemon's primary type if not specified.
+   *
+   * This function only mocks the Pokemon's tera-related variables; it does NOT activate any tera-related abilities.
+   *
+   * @param pokemon - The pokemon to terastallize.
+   * @param teraType - (optional) The {@linkcode PokemonType} to terastallize it as.
+   */
+  public forceTera(pokemon: Pokemon, teraType?: PokemonType): void {
+    vi.spyOn(pokemon, "isTerastallized", "get").mockReturnValue(true);
+    teraType ??= pokemon.getSpeciesForm(true).type1;
+    vi.spyOn(pokemon, "teraType", "get").mockReturnValue(teraType);
+  }
+}

test/testUtils/helpers/moveHelper.ts

@@ -1,14 +1,16 @@
 import type { BattlerIndex } from "#app/battle";
+import { getMoveTargets } from "#app/data/moves/move";
 import { Button } from "#app/enums/buttons";
 import type Pokemon from "#app/field/pokemon";
 import { PokemonMove } from "#app/field/pokemon";
 import Overrides from "#app/overrides";
 import type { CommandPhase } from "#app/phases/command-phase";
+import type { EnemyCommandPhase } from "#app/phases/enemy-command-phase";
 import { LearnMovePhase } from "#app/phases/learn-move-phase";
 import { MoveEffectPhase } from "#app/phases/move-effect-phase";
 import { Command } from "#app/ui/command-ui-handler";
-import { UiMode } from "#enums/ui-mode";
 import { Moves } from "#enums/moves";
+import { UiMode } from "#enums/ui-mode";
 import { getMovePosition } from "#test/testUtils/gameManagerUtils";
 import { GameManagerHelper } from "#test/testUtils/helpers/gameManagerHelper";
 import { vi } from "vitest";
@@ -92,6 +94,35 @@ export class MoveHelper extends GameManagerHelper {
     }
   }
 
+  /**
+   * Modifies a player pokemon's moveset to contain only the selected move and then
+   * selects it to be used during the next {@linkcode CommandPhase}.
+   *
+   * Warning: Will disable the player moveset override if it is enabled!
+   *
+   * Note: If you need to check for changes in the player's moveset as part of the test, it may be
+   * best to use {@linkcode changeMoveset} and {@linkcode select} instead.
+   * @param moveId - the move to use
+   * @param pkmIndex - the pokemon index. Relevant for double-battles only (defaults to 0)
+   * @param targetIndex - (optional) The {@linkcode BattlerIndex} of the Pokemon to target for single-target moves, or `null` if a manual call to `selectTarget()` is required
+   * @param useTera - If `true`, the Pokemon also chooses to Terastallize. This does not require a Tera Orb. Default: `false`.
+   */
+  public use(moveId: Moves, pkmIndex: 0 | 1 = 0, targetIndex?: BattlerIndex | null, useTera = false): void {
+    if ([Overrides.MOVESET_OVERRIDE].flat().length > 0) {
+      vi.spyOn(Overrides, "MOVESET_OVERRIDE", "get").mockReturnValue([]);
+      console.warn("Warning: `use` overwrites the Pokemon's moveset and disables the player moveset override!");
+    }
+
+    const pokemon = this.game.scene.getPlayerField()[pkmIndex];
+    pokemon.moveset = [new PokemonMove(moveId)];
+
+    if (useTera) {
+      this.selectWithTera(moveId, pkmIndex, targetIndex);
+      return;
+    }
+    this.select(moveId, pkmIndex, targetIndex);
+  }
+
   /**
    * Forces the Paralysis or Freeze status to activate on the next move by temporarily mocking {@linkcode Overrides.STATUS_ACTIVATION_OVERRIDE},
    * advancing to the next `MovePhase`, and then resetting the override to `null`
@@ -132,6 +163,77 @@ export class MoveHelper extends GameManagerHelper {
     console.log(`Pokemon ${pokemon.species.name}'s moveset manually set to ${movesetStr} (=[${moveset.join(", ")}])!`);
   }
 
+  /**
+   * Forces the next enemy selecting a move to use the given move in its moveset
+   * against the given target (if applicable).
+   * @param moveId The {@linkcode MoveId | move} the enemy will use
+   * @param target (Optional) the {@linkcode BattlerIndex | target} which the enemy will use the given move against
+   */
+  public async selectEnemyMove(moveId: Moves, target?: BattlerIndex) {
+    // Wait for the next EnemyCommandPhase to start
+    await this.game.phaseInterceptor.to("EnemyCommandPhase", false);
+    const enemy =
+      this.game.scene.getEnemyField()[(this.game.scene.getCurrentPhase() as EnemyCommandPhase).getFieldIndex()];
+    const legalTargets = getMoveTargets(enemy, moveId);
+
+    vi.spyOn(enemy, "getNextMove").mockReturnValueOnce({
+      move: moveId,
+      targets:
+        target !== undefined && !legalTargets.multiple && legalTargets.targets.includes(target)
+          ? [target]
+          : enemy.getNextTargets(moveId),
+    });
+
+    /**
+     * Run the EnemyCommandPhase to completion.
+     * This allows this function to be called consecutively to
+     * force a move for each enemy in a double battle.
+     */
+    await this.game.phaseInterceptor.to("EnemyCommandPhase");
+  }
+
+  /**
+   * Forces the next enemy selecting a move to use the given move against the given target (if applicable).
+   *
+   * Warning: Overwrites the pokemon's moveset and disables the moveset override!
+   *
+   * Note: If you need to check for changes in the enemy's moveset as part of the test, it may be
+   * best to use {@linkcode changeMoveset} and {@linkcode selectEnemyMove} instead.
+   * @param moveId The {@linkcode MoveId | move} the enemy will use
+   * @param target (Optional) the {@linkcode BattlerIndex | target} which the enemy will use the given move against
+   */
+  public async forceEnemyMove(moveId: Moves, target?: BattlerIndex) {
+    // Wait for the next EnemyCommandPhase to start
+    await this.game.phaseInterceptor.to("EnemyCommandPhase", false);
+
+    const enemy =
+      this.game.scene.getEnemyField()[(this.game.scene.getCurrentPhase() as EnemyCommandPhase).getFieldIndex()];
+
+    if ([Overrides.OPP_MOVESET_OVERRIDE].flat().length > 0) {
+      vi.spyOn(Overrides, "OPP_MOVESET_OVERRIDE", "get").mockReturnValue([]);
+      console.warn(
+        "Warning: `forceEnemyMove` overwrites the Pokemon's moveset and disables the enemy moveset override!",
+      );
+    }
+    enemy.moveset = [new PokemonMove(moveId)];
+    const legalTargets = getMoveTargets(enemy, moveId);
+
+    vi.spyOn(enemy, "getNextMove").mockReturnValueOnce({
+      move: moveId,
+      targets:
+        target !== undefined && !legalTargets.multiple && legalTargets.targets.includes(target)
+          ? [target]
+          : enemy.getNextTargets(moveId),
+    });
+
+    /**
+     * Run the EnemyCommandPhase to completion.
+     * This allows this function to be called consecutively to
+     * force a move for each enemy in a double battle.
+     */
+    await this.game.phaseInterceptor.to("EnemyCommandPhase");
+  }
+
   /**
    * Simulates learning a move for a player pokemon.
    * @param move The {@linkcode Moves} being learnt