[Fix] Ability suppression effects not failing correctly (#2440)

* Make ability suppression fail if ability is already suppressed

* Document SuppressAbilitiesAttr

* Add gastro acid unit tests

src/data/move.ts

@@ -5290,7 +5290,16 @@ export class SwitchAbilitiesAttr extends MoveEffectAttr {
   }
 }
 
+/**
+ * Attribute used for moves that suppress abilities like {@linkcode Moves.GASTRO_ACID}.
+ * A suppressed ability cannot be activated.
+ *
+ * @extends MoveEffectAttr
+ * @see {@linkcode apply}
+ * @see {@linkcode getCondition}
+ */
 export class SuppressAbilitiesAttr extends MoveEffectAttr {
+  /** Sets ability suppression for the target pokemon and displays a message. */
   apply(user: Pokemon, target: Pokemon, move: Move, args: any[]): boolean {
     if (!super.apply(user, target, move, args)) {
       return false;
@@ -5303,8 +5312,9 @@ export class SuppressAbilitiesAttr extends MoveEffectAttr {
     return true;
   }
 
+  /** Causes the effect to fail when the target's ability is unsupressable or already suppressed. */
   getCondition(): MoveConditionFunc {
-    return (user, target, move) => !target.getAbility().hasAttr(UnsuppressableAbilityAbAttr);
+    return (user, target, move) => !target.getAbility().hasAttr(UnsuppressableAbilityAbAttr) && !target.summonData.abilitySuppressed;
   }
 }
 
@@ -5319,7 +5329,7 @@ export class SuppressAbilitiesIfActedAttr extends MoveEffectAttr {
    * abillity cannot be suppressed. This is a secondary effect and has no bearing on the success or failure of the move.
    *
    * @returns True if the move occurred, otherwise false. Note that true will be returned even if the target has not
-   * yet moved or if the target's abiilty is un-suppressable.
+   * yet moved or if the suppression failed to apply.
    */
   apply(user: Pokemon, target: Pokemon, move: Move, args: any[]): boolean {
     if (!super.apply(user, target, move, args)) {

src/test/moves/gastro_acid.test.ts

@@ -0,0 +1,91 @@
+import { afterEach, beforeAll, beforeEach, describe, expect, it, vi } from "vitest";
+import GameManager from "../utils/gameManager";
+import {
+  Moves
+} from "#app/enums/moves.js";
+import * as overrides from "#app/overrides";
+import { Abilities } from "#app/enums/abilities.js";
+import { BattlerIndex } from "#app/battle.js";
+import { getMovePosition } from "../utils/gameManagerUtils";
+import { MoveResult } from "#app/field/pokemon.js";
+import { Stat } from "#app/data/pokemon-stat.js";
+
+const TIMEOUT = 20 * 1000;
+
+describe("Moves - Gastro Acid", () => {
+  let phaserGame: Phaser.Game;
+  let game: GameManager;
+
+  beforeAll(() => {
+    phaserGame = new Phaser.Game({
+      type: Phaser.HEADLESS,
+    });
+  });
+
+  afterEach(() => {
+    game.phaseInterceptor.restoreOg();
+  });
+
+  beforeEach(() => {
+    game = new GameManager(phaserGame);
+    vi.spyOn(overrides, "DOUBLE_BATTLE_OVERRIDE", "get").mockReturnValue(true);
+    vi.spyOn(overrides, "STARTING_LEVEL_OVERRIDE", "get").mockReturnValue(1);
+    vi.spyOn(overrides, "OPP_LEVEL_OVERRIDE", "get").mockReturnValue(100);
+    vi.spyOn(overrides, "ABILITY_OVERRIDE", "get").mockReturnValue(Abilities.NONE);
+    vi.spyOn(overrides, "MOVESET_OVERRIDE", "get").mockReturnValue([Moves.GASTRO_ACID, Moves.WATER_GUN, Moves.SPLASH, Moves.CORE_ENFORCER]);
+    vi.spyOn(overrides, "OPP_MOVESET_OVERRIDE", "get").mockReturnValue([Moves.SPLASH, Moves.SPLASH, Moves.SPLASH, Moves.SPLASH]);
+    vi.spyOn(overrides, "OPP_ABILITY_OVERRIDE", "get").mockReturnValue(Abilities.WATER_ABSORB);
+  });
+
+  it("suppresses effect of ability", async () => {
+    /*
+     * Expected flow (enemies have WATER ABSORD, can only use SPLASH)
+     * - player mon 1 uses GASTRO ACID, player mon 2 uses SPLASH
+     * - both player mons use WATER GUN on their respective enemy mon
+     * - player mon 1 should have dealt damage, player mon 2 should have not
+     */
+
+    await game.startBattle();
+
+    game.doAttack(getMovePosition(game.scene, 0, Moves.GASTRO_ACID));
+    game.doSelectTarget(BattlerIndex.ENEMY);
+    game.doAttack(getMovePosition(game.scene, 0, Moves.SPLASH));
+    game.doSelectTarget(BattlerIndex.PLAYER_2);
+
+    await game.phaseInterceptor.to("TurnInitPhase");
+
+    const enemyField = game.scene.getEnemyField();
+    expect(enemyField[0].summonData.abilitySuppressed).toBe(true);
+    expect(enemyField[1].summonData.abilitySuppressed).toBe(false);
+
+    game.doAttack(getMovePosition(game.scene, 0, Moves.WATER_GUN));
+    game.doSelectTarget(BattlerIndex.ENEMY);
+    game.doAttack(getMovePosition(game.scene, 0, Moves.WATER_GUN));
+    game.doSelectTarget(BattlerIndex.ENEMY_2);
+
+    await game.phaseInterceptor.to("TurnEndPhase");
+
+    expect(enemyField[0].hp).toBeLessThan(enemyField[0].getMaxHp());
+    expect(enemyField[1].hp).toBe(enemyField[1].getMaxHp());
+  }, TIMEOUT);
+
+  it("fails if used on an enemy with an already-suppressed ability", async () => {
+    vi.spyOn(overrides, "DOUBLE_BATTLE_OVERRIDE", "get").mockReturnValue(false);
+
+    await game.startBattle();
+
+    // Force player to be slower to enable Core Enforcer to proc its suppression effect
+    game.scene.getPlayerPokemon().stats[Stat.SPD] = 1;
+    game.scene.getEnemyPokemon().stats[Stat.SPD] = 2;
+
+    game.doAttack(getMovePosition(game.scene, 0, Moves.CORE_ENFORCER));
+
+    await game.phaseInterceptor.to("TurnInitPhase");
+
+    game.doAttack(getMovePosition(game.scene, 0, Moves.GASTRO_ACID));
+
+    await game.phaseInterceptor.to("TurnInitPhase");
+
+    expect(game.scene.getPlayerPokemon().getLastXMoves()[0].result).toBe(MoveResult.FAIL);
+  }, TIMEOUT);
+});