[Item] Implement Eviolite Behavior (#2161)

* Add Eviolite with Unit Tests

* Localize for de, es, fr, it, ko, zh_CN, zh_TW

* Adjust German Localization

Co-authored-by: Jannik Tappert <38758606+CodeTappert@users.noreply.github.com>

* Adjust Italian Localization

* Change Multiplier Type

* Adjust Unit Test Import

* Change Constructor

* Make Unit Tests Localized

* Comment Out of Reward Pool

---------

Co-authored-by: Jannik Tappert <38758606+CodeTappert@users.noreply.github.com>

src/field/pokemon.ts

@@ -10,7 +10,7 @@ import * as Utils from "../utils";
 import { Type, TypeDamageMultiplier, getTypeDamageMultiplier, getTypeRgb } from "../data/type";
 import { getLevelTotalExp } from "../data/exp";
 import { Stat } from "../data/pokemon-stat";
-import { AttackTypeBoosterModifier, DamageMoneyRewardModifier, EnemyDamageBoosterModifier, EnemyDamageReducerModifier, EnemyEndureChanceModifier, EnemyFusionChanceModifier, HiddenAbilityRateBoosterModifier, PokemonBaseStatModifier, PokemonFriendshipBoosterModifier, PokemonHeldItemModifier, PokemonMultiHitModifier, PokemonNatureWeightModifier, ShinyRateBoosterModifier, SurviveDamageModifier, TempBattleStatBoosterModifier, TerastallizeModifier } from "../modifier/modifier";
+import { AttackTypeBoosterModifier, DamageMoneyRewardModifier, EnemyDamageBoosterModifier, EnemyDamageReducerModifier, EnemyEndureChanceModifier, EnemyFusionChanceModifier, HiddenAbilityRateBoosterModifier, PokemonBaseStatModifier, PokemonFriendshipBoosterModifier, PokemonHeldItemModifier, PokemonMultiHitModifier, PokemonNatureWeightModifier, ShinyRateBoosterModifier, SurviveDamageModifier, TempBattleStatBoosterModifier, EvolutionStatBoosterModifier, TerastallizeModifier } from "../modifier/modifier";
 import { PokeballType } from "../data/pokeball";
 import { Gender } from "../data/gender";
 import { initMoveAnim, loadMoveAnimAssets } from "../data/battle-anims";
@@ -657,6 +657,8 @@ export default abstract class Pokemon extends Phaser.GameObjects.Container {
       this.scene.applyModifiers(TempBattleStatBoosterModifier, this.isPlayer(), battleStat as integer as TempBattleStat, statLevel);
     }
     const statValue = new Utils.NumberHolder(this.getStat(stat));
+    this.scene.applyModifiers(EvolutionStatBoosterModifier, this.isPlayer(), this, stat, statValue);
+
     const fieldApplied = new Utils.BooleanHolder(false);
     for (const pokemon of this.scene.getField(true)) {
       applyFieldBattleStatMultiplierAbAttrs(FieldMultiplyBattleStatAbAttr, pokemon, stat, statValue, this, fieldApplied);

src/locales/de/modifier-type.ts

@@ -182,6 +182,8 @@ export const modifierType: ModifierTypeTranslationEntries = {
 
     "SOOTHE_BELL": { name: "Sanftglocke" },
 
+    "EVIOLITE": { name: "Evolith", description: "Ein mysteriöser Klumpen, der die Vert. u. Spez.-Vert. von Pokémon erhöht, die sich noch entwickeln können." },
+
     "SOUL_DEW": { name: "Seelentau", description: "Erhöht den Einfluss des Wesens eines Pokemon auf seine Werte um 10% (additiv)." },
 
     "NUGGET": { name: "Nugget" },

src/locales/en/modifier-type.ts

@@ -182,6 +182,8 @@ export const modifierType: ModifierTypeTranslationEntries = {
 
     "SOOTHE_BELL": { name: "Soothe Bell" },
 
+    "EVIOLITE": { name: "Eviolite", description: "This mysterious evolutionary lump boosts the Defense and Sp. Def stats when held by a Pokémon that can still evolve." },
+
     "SOUL_DEW": { name: "Soul Dew", description: "Increases the influence of a Pokémon's nature on its stats by 10% (additive)." },
 
     "NUGGET": { name: "Nugget" },

src/locales/es/modifier-type.ts

@@ -182,6 +182,8 @@ export const modifierType: ModifierTypeTranslationEntries = {
 
     "SOOTHE_BELL": { name: "Camp. Alivio" },
 
+    "EVIOLITE": { name: "Mineral Evolutivo", description: "Roca misteriosa. El Pokémon portador aumentará su Defensa y su Defensa Especial si aún puede evolucionar." },
+
     "SOUL_DEW": { name: "Rocío bondad", description: "Aumenta la influencia de la naturaleza de un Pokémon en sus estadísticas en un 10% (aditivo)." },
 
     "NUGGET": { name: "Pepita" },

src/locales/fr/modifier-type.ts

@@ -182,6 +182,8 @@ export const modifierType: ModifierTypeTranslationEntries = {
 
     "SOOTHE_BELL": { name: "Grelot Zen" },
 
+    "EVIOLITE": { name: "Évoluroc", description: "Un étrange concentré d’évolution qui augmente la Défense et la Défense Spéciale d’un Pokémon pouvant évoluer." },
+
     "SOUL_DEW": { name: "Rosée Âme", description: "Augmente de 10% l’influence de la nature d’un Pokémon sur ses statistiques (cumulatif)." },
 
     "NUGGET": { name: "Pépite" },

src/locales/it/modifier-type.ts

@@ -182,6 +182,8 @@ export const modifierType: ModifierTypeTranslationEntries = {
 
     "SOOTHE_BELL": { name: "Calmanella" },
 
+    "EVIOLITE": { name: "Evolcondensa", description: "Misteriosa materia evolutiva. Aumenta la Difesa e la Difesa Speciale di un Pokémon che può ancora evolversi." },
+
     "SOUL_DEW": { name: "Cuorugiada", description: "Aumenta del 10% l'influenza della natura di un Pokémon sulle sue statistiche (Aggiuntivo)." },
 
     "NUGGET": { name: "Pepita" },

src/locales/ko/modifier-type.ts

@@ -182,6 +182,8 @@ export const modifierType: ModifierTypeTranslationEntries = {
 
     "SOOTHE_BELL": { name: "평온의방울" },
 
+    "EVIOLITE": { name: "진화의휘석", description: "진화의 이상한 덩어리. 지니게 하면 진화 전 포켓몬의 방어와 특수방어가 올라간다." },
+
     "SOUL_DEW": { name: "마음의물방울", description: "지닌 포켓몬의 성격의 효과가 10% 증가한다 (합연산)." },
 
     "NUGGET": { name: "금구슬" },

src/locales/zh_CN/modifier-type.ts

@@ -182,6 +182,8 @@ export const modifierType: ModifierTypeTranslationEntries = {
 
     "SOOTHE_BELL": { name: "安抚之铃" },
 
+    "EVIOLITE": { name: "进化奇石", description: "进化的神奇石块。携带后，还能进化的宝可梦的 防御和特防就会提高。" },
+
     "SOUL_DEW": { name: "心之水滴", description: "增加宝可梦性格影响10% (加算)。" },
 
     "NUGGET": { name: "金珠" },

src/locales/zh_TW/modifier-type.ts

@@ -187,6 +187,10 @@ export const modifierType: ModifierTypeTranslationEntries = {
     LUCKY_EGG: { name: "幸運蛋" },
     GOLDEN_EGG: { name: "金蛋" },
     SOOTHE_BELL: { name: "安撫之鈴" },
+    EVIOLITE: {
+      name: "進化奇石",
+      description: "進化的神奇石塊。攜帶後，還能進化的寶可夢的 防禦和特防就會提高。"
+    },
     SOUL_DEW: {
       name: "心之水滴",
       description: "增加寶可夢性格影響10% (加算)。",

src/modifier/modifier-type.ts

@@ -1193,6 +1193,8 @@ export const modifierTypes = {
 
   SOOTHE_BELL: () => new PokemonFriendshipBoosterModifierType("modifierType:ModifierType.SOOTHE_BELL", "soothe_bell"),
 
+  EVIOLITE: () => new PokemonHeldItemModifierType("modifierType:ModifierType.EVIOLITE", "eviolite", (type, args) => new Modifiers.EvolutionStatBoosterModifier(type, (args[0] as Pokemon).id, [Stat.DEF, Stat.SPDEF], 1.5)),
+
   SOUL_DEW: () => new PokemonHeldItemModifierType("modifierType:ModifierType.SOUL_DEW", "soul_dew", (type, args) => new Modifiers.PokemonNatureWeightModifier(type, (args[0] as Pokemon).id)),
 
   NUGGET: () => new MoneyRewardModifierType("modifierType:ModifierType.NUGGET", "nugget", 1, "modifierType:ModifierType.MoneyRewardModifierType.extra.small"),
@@ -1366,6 +1368,7 @@ const modifierPool: ModifierPool = {
     new WeightedModifierType(modifierTypes.MINT, 4),
     new WeightedModifierType(modifierTypes.RARE_EVOLUTION_ITEM, (party: Pokemon[]) => Math.min(Math.ceil(party[0].scene.currentBattle.waveIndex / 15) * 4, 32), 32),
     new WeightedModifierType(modifierTypes.AMULET_COIN, 3),
+    //new WeightedModifierType(modifierTypes.EVIOLITE, (party: Pokemon[]) => party.some(p => ((p.getSpeciesForm(true).speciesId in pokemonEvolutions) || (p.isFusion() && (p.getFusionSpeciesForm(true).speciesId in pokemonEvolutions))) && !p.getHeldItems().some(i => i instanceof Modifiers.EvolutionStatBoosterModifier)) ? 10 : 0),
     new WeightedModifierType(modifierTypes.TOXIC_ORB, (party: Pokemon[]) => {
       const checkedAbilities = [Abilities.QUICK_FEET, Abilities.GUTS, Abilities.MARVEL_SCALE, Abilities.TOXIC_BOOST, Abilities.POISON_HEAL, Abilities.MAGIC_GUARD];
       const checkedMoves = [Moves.FACADE, Moves.TRICK, Moves.FLING, Moves.SWITCHEROO, Moves.PSYCHO_SHIFT];

src/modifier/modifier.ts

@@ -706,6 +706,83 @@ export class PokemonBaseStatModifier extends PokemonHeldItemModifier {
   }
 }
 
+/**
+ * Modifier used for held items, specifically Eviolite, that apply
+ * {@linkcode Stat} boost(s) using a multiplier if the holder can evolve.
+ * @extends PokemonHeldItemModifier
+ * @see {@linkcode apply}
+ */
+export class EvolutionStatBoosterModifier extends PokemonHeldItemModifier {
+  /** The stats that the held item boosts */
+  private stats: Stat[];
+  /** The multiplier used to increase the relevant stat(s) */
+  private multiplier: number;
+
+  constructor(type: ModifierType, pokemonId: integer, stats: Stat[], multiplier: number, stackCount?: integer) {
+    super(type, pokemonId, stackCount);
+
+    this.stats = stats;
+    this.multiplier = multiplier;
+  }
+
+  clone() {
+    return new EvolutionStatBoosterModifier(this.type, this.pokemonId, this.stats, this.multiplier, this.stackCount);
+  }
+
+  getArgs(): any[] {
+    return [ ...super.getArgs(), this.stats, this.multiplier ];
+  }
+
+  matchType(modifier: Modifier): boolean {
+    return modifier instanceof EvolutionStatBoosterModifier;
+  }
+
+  /**
+   * Checks if the incoming stat is listed in {@linkcode stats}
+   * @param args [0] {@linkcode Pokemon} N/A
+   *             [1] {@linkcode Stat} being checked at the time
+   *             [2] {@linkcode Utils.NumberHolder} N/A
+   * @returns true if the stat could be boosted, false otherwise
+   */
+  shouldApply(args: any[]): boolean {
+    return this.stats.includes(args[1] as Stat);
+  }
+
+  /**
+   * Boosts the incoming stat value by a {@linkcode multiplier} if the holder
+   * can evolve. Note that, if the holder is a fusion, they will receive
+   * only half of the boost if either of the fused members are fully
+   * evolved. However, if they are both unevolved, the full boost
+   * will apply.
+   * @param args [0] {@linkcode Pokemon} that holds the held item
+   *             [1] {@linkcode Stat} N/A
+   *             [2] {@linkcode Utils.NumberHolder} that holds the resulting value of the stat
+   * @returns true if the stat boost applies successfully, false otherwise
+   * @see shouldApply
+   */
+  apply(args: any[]): boolean {
+    const holder = args[0] as Pokemon;
+    const statValue = args[2] as Utils.NumberHolder;
+    const isUnevolved = holder.getSpeciesForm(true).speciesId in pokemonEvolutions;
+
+    if (holder.isFusion() && (holder.getFusionSpeciesForm(true).speciesId in pokemonEvolutions) !== isUnevolved) {
+      // Half boost applied if holder is fused and either part of fusion is fully evolved
+      statValue.value *= 1 + (this.multiplier - 1) / 2;
+      return true;
+    } else if (isUnevolved) {
+      // Full boost applied if holder is unfused and unevolved or, if fused, both parts of fusion are unevolved
+      statValue.value *= this.multiplier;
+      return true;
+    }
+
+    return false;
+  }
+
+  getMaxHeldItemCount(_pokemon: Pokemon): integer {
+    return 1;
+  }
+}
+
 /**
  * Applies Specific Type item boosts (e.g., Magnet)
  */

src/test/items/eviolite.test.ts

@@ -0,0 +1,278 @@
+import { afterEach, beforeAll, beforeEach, describe, expect, it, vi } from "vitest";
+import Phase from "phaser";
+import GameManager from "#app/test/utils/gameManager";
+import * as overrides from "#app/overrides";
+import { Stat } from "#app/data/pokemon-stat";
+import { EvolutionStatBoosterModifier } from "#app/modifier/modifier";
+import { modifierTypes } from "#app/modifier/modifier-type";
+import * as Utils from "#app/utils";
+import i18next from "#app/plugins/i18n";
+import { Species } from "#enums/species";
+
+describe("Items - Eviolite", () => {
+  let phaserGame: Phaser.Game;
+  let game: GameManager;
+
+  beforeAll(() => {
+    phaserGame = new Phase.Game({
+      type: Phaser.HEADLESS,
+    });
+  });
+
+  afterEach(() => {
+    game.phaseInterceptor.restoreOg();
+  });
+
+  beforeEach(() => {
+    game = new GameManager(phaserGame);
+
+    vi.spyOn(overrides, "SINGLE_BATTLE_OVERRIDE", "get").mockReturnValue(true);
+  });
+
+  it("EVIOLITE activates in battle correctly", async() => {
+    vi.spyOn(overrides, "STARTING_HELD_ITEMS_OVERRIDE", "get").mockReturnValue([{ name: "EVIOLITE" }]);
+    const consoleSpy = vi.spyOn(console, "log");
+    await game.startBattle([
+      Species.PICHU
+    ]);
+
+    const partyMember = game.scene.getParty()[0];
+
+    // Checking consoe log to make sure Eviolite is applied when getBattleStat (with the appropriate stat) is called
+    partyMember.getBattleStat(Stat.DEF);
+    expect(consoleSpy).toHaveBeenLastCalledWith("Applied", i18next.t("modifierType:ModifierType.EVIOLITE.name"), "");
+
+    // Printing dummy console messages along the way so subsequent checks don't pass because of the first
+    console.log("");
+
+    partyMember.getBattleStat(Stat.SPDEF);
+    expect(consoleSpy).toHaveBeenLastCalledWith("Applied", i18next.t("modifierType:ModifierType.EVIOLITE.name"), "");
+
+    console.log("");
+
+    partyMember.getBattleStat(Stat.ATK);
+    expect(consoleSpy).not.toHaveBeenLastCalledWith("Applied", i18next.t("modifierType:ModifierType.EVIOLITE.name"), "");
+
+    console.log("");
+
+    partyMember.getBattleStat(Stat.SPATK);
+    expect(consoleSpy).not.toHaveBeenLastCalledWith("Applied", i18next.t("modifierType:ModifierType.EVIOLITE.name"), "");
+
+    console.log("");
+
+    partyMember.getBattleStat(Stat.SPD);
+    expect(consoleSpy).not.toHaveBeenLastCalledWith("Applied", i18next.t("modifierType:ModifierType.EVIOLITE.name"), "");
+  });
+
+  it("EVIOLITE held by unevolved, unfused pokemon", async() => {
+    await game.startBattle([
+      Species.PICHU
+    ]);
+
+    const partyMember = game.scene.getParty()[0];
+
+    const defStat = partyMember.getStat(Stat.DEF);
+    const spDefStat = partyMember.getStat(Stat.SPDEF);
+
+    // Making sure modifier is not applied without holding item
+    const defValue = new Utils.NumberHolder(defStat);
+    partyMember.scene.applyModifiers(EvolutionStatBoosterModifier, true, partyMember, Stat.DEF, defValue);
+    const spDefValue = new Utils.NumberHolder(spDefStat);
+    partyMember.scene.applyModifiers(EvolutionStatBoosterModifier, true, partyMember, Stat.SPDEF, spDefValue);
+
+    expect(defValue.value / defStat).toBe(1);
+    expect(spDefValue.value / spDefStat).toBe(1);
+
+    // Giving Eviolite to party member and testing if it applies
+    partyMember.scene.addModifier(modifierTypes.EVIOLITE().newModifier(partyMember), true);
+    partyMember.scene.applyModifiers(EvolutionStatBoosterModifier, true, partyMember, Stat.DEF, defValue);
+    partyMember.scene.applyModifiers(EvolutionStatBoosterModifier, true, partyMember, Stat.SPDEF, spDefValue);
+
+    expect(defValue.value / defStat).toBe(1.5);
+    expect(spDefValue.value / spDefStat).toBe(1.5);
+  }, 20000);
+
+  it("EVIOLITE held by fully evolved, unfused pokemon", async() => {
+    await game.startBattle([
+      Species.RAICHU,
+    ]);
+
+    const partyMember = game.scene.getParty()[0];
+
+    const defStat = partyMember.getStat(Stat.DEF);
+    const spDefStat = partyMember.getStat(Stat.SPDEF);
+
+    // Making sure modifier is not applied without holding item
+    const defValue = new Utils.NumberHolder(defStat);
+    partyMember.scene.applyModifiers(EvolutionStatBoosterModifier, true, partyMember, Stat.DEF, defValue);
+    const spDefValue = new Utils.NumberHolder(spDefStat);
+    partyMember.scene.applyModifiers(EvolutionStatBoosterModifier, true, partyMember, Stat.SPDEF, spDefValue);
+
+    expect(defValue.value / defStat).toBe(1);
+    expect(spDefValue.value / spDefStat).toBe(1);
+
+    // Giving Eviolite to party member and testing if it applies
+    partyMember.scene.addModifier(modifierTypes.EVIOLITE().newModifier(partyMember), true);
+    partyMember.scene.applyModifiers(EvolutionStatBoosterModifier, true, partyMember, Stat.DEF, defValue);
+    partyMember.scene.applyModifiers(EvolutionStatBoosterModifier, true, partyMember, Stat.SPDEF, spDefValue);
+
+    expect(defValue.value / defStat).toBe(1);
+    expect(spDefValue.value / spDefStat).toBe(1);
+  }, 20000);
+
+  it("EVIOLITE held by completely unevolved, fused pokemon", async() => {
+    await game.startBattle([
+      Species.PICHU,
+      Species.CLEFFA
+    ]);
+
+    const partyMember = game.scene.getParty()[0];
+    const ally = game.scene.getParty()[1];
+
+    // Fuse party members (taken from PlayerPokemon.fuse(...) function)
+    partyMember.fusionSpecies = ally.species;
+    partyMember.fusionFormIndex = ally.formIndex;
+    partyMember.fusionAbilityIndex = ally.abilityIndex;
+    partyMember.fusionShiny = ally.shiny;
+    partyMember.fusionVariant = ally.variant;
+    partyMember.fusionGender = ally.gender;
+    partyMember.fusionLuck = ally.luck;
+
+    const defStat = partyMember.getStat(Stat.DEF);
+    const spDefStat = partyMember.getStat(Stat.SPDEF);
+
+    // Making sure modifier is not applied without holding item
+    const defValue = new Utils.NumberHolder(defStat);
+    partyMember.scene.applyModifiers(EvolutionStatBoosterModifier, true, partyMember, Stat.DEF, defValue);
+    const spDefValue = new Utils.NumberHolder(spDefStat);
+    partyMember.scene.applyModifiers(EvolutionStatBoosterModifier, true, partyMember, Stat.SPDEF, spDefValue);
+
+    expect(defValue.value / defStat).toBe(1);
+    expect(spDefValue.value / spDefStat).toBe(1);
+
+    // Giving Eviolite to party member and testing if it applies
+    partyMember.scene.addModifier(modifierTypes.EVIOLITE().newModifier(partyMember), true);
+    partyMember.scene.applyModifiers(EvolutionStatBoosterModifier, true, partyMember, Stat.DEF, defValue);
+    partyMember.scene.applyModifiers(EvolutionStatBoosterModifier, true, partyMember, Stat.SPDEF, spDefValue);
+
+    expect(defValue.value / defStat).toBe(1.5);
+    expect(spDefValue.value / spDefStat).toBe(1.5);
+  }, 20000);
+
+  it("EVIOLITE held by partially unevolved (base), fused pokemon", async() => {
+    await game.startBattle([
+      Species.PICHU,
+      Species.CLEFABLE
+    ]);
+
+    const partyMember = game.scene.getParty()[0];
+    const ally = game.scene.getParty()[1];
+
+    // Fuse party members (taken from PlayerPokemon.fuse(...) function)
+    partyMember.fusionSpecies = ally.species;
+    partyMember.fusionFormIndex = ally.formIndex;
+    partyMember.fusionAbilityIndex = ally.abilityIndex;
+    partyMember.fusionShiny = ally.shiny;
+    partyMember.fusionVariant = ally.variant;
+    partyMember.fusionGender = ally.gender;
+    partyMember.fusionLuck = ally.luck;
+
+    const defStat = partyMember.getStat(Stat.DEF);
+    const spDefStat = partyMember.getStat(Stat.SPDEF);
+
+    // Making sure modifier is not applied without holding item
+    const defValue = new Utils.NumberHolder(defStat);
+    partyMember.scene.applyModifiers(EvolutionStatBoosterModifier, true, partyMember, Stat.DEF, defValue);
+    const spDefValue = new Utils.NumberHolder(spDefStat);
+    partyMember.scene.applyModifiers(EvolutionStatBoosterModifier, true, partyMember, Stat.SPDEF, spDefValue);
+
+    expect(defValue.value / defStat).toBe(1);
+    expect(spDefValue.value / spDefStat).toBe(1);
+
+    // Giving Eviolite to party member and testing if it applies
+    partyMember.scene.addModifier(modifierTypes.EVIOLITE().newModifier(partyMember), true);
+    partyMember.scene.applyModifiers(EvolutionStatBoosterModifier, true, partyMember, Stat.DEF, defValue);
+    partyMember.scene.applyModifiers(EvolutionStatBoosterModifier, true, partyMember, Stat.SPDEF, spDefValue);
+
+    expect(defValue.value / defStat).toBe(1.25);
+    expect(spDefValue.value / spDefStat).toBe(1.25);
+  }, 20000);
+
+  it("EVIOLITE held by partially unevolved (fusion), fused pokemon", async() => {
+    await game.startBattle([
+      Species.RAICHU,
+      Species.CLEFFA
+    ]);
+
+    const partyMember = game.scene.getParty()[0];
+    const ally = game.scene.getParty()[1];
+
+    // Fuse party members (taken from PlayerPokemon.fuse(...) function)
+    partyMember.fusionSpecies = ally.species;
+    partyMember.fusionFormIndex = ally.formIndex;
+    partyMember.fusionAbilityIndex = ally.abilityIndex;
+    partyMember.fusionShiny = ally.shiny;
+    partyMember.fusionVariant = ally.variant;
+    partyMember.fusionGender = ally.gender;
+    partyMember.fusionLuck = ally.luck;
+
+    const defStat = partyMember.getStat(Stat.DEF);
+    const spDefStat = partyMember.getStat(Stat.SPDEF);
+
+    // Making sure modifier is not applied without holding item
+    const defValue = new Utils.NumberHolder(defStat);
+    partyMember.scene.applyModifiers(EvolutionStatBoosterModifier, true, partyMember, Stat.DEF, defValue);
+    const spDefValue = new Utils.NumberHolder(spDefStat);
+    partyMember.scene.applyModifiers(EvolutionStatBoosterModifier, true, partyMember, Stat.SPDEF, spDefValue);
+
+    expect(defValue.value / defStat).toBe(1);
+    expect(spDefValue.value / spDefStat).toBe(1);
+
+    // Giving Eviolite to party member and testing if it applies
+    partyMember.scene.addModifier(modifierTypes.EVIOLITE().newModifier(partyMember), true);
+    partyMember.scene.applyModifiers(EvolutionStatBoosterModifier, true, partyMember, Stat.DEF, defValue);
+    partyMember.scene.applyModifiers(EvolutionStatBoosterModifier, true, partyMember, Stat.SPDEF, spDefValue);
+
+    expect(defValue.value / defStat).toBe(1.25);
+    expect(spDefValue.value / spDefStat).toBe(1.25);
+  }, 20000);
+
+  it("EVIOLITE held by completely evolved, fused pokemon", async() => {
+    await game.startBattle([
+      Species.RAICHU,
+      Species.CLEFABLE
+    ]);
+
+    const partyMember = game.scene.getParty()[0];
+    const ally = game.scene.getParty()[1];
+
+    // Fuse party members (taken from PlayerPokemon.fuse(...) function)
+    partyMember.fusionSpecies = ally.species;
+    partyMember.fusionFormIndex = ally.formIndex;
+    partyMember.fusionAbilityIndex = ally.abilityIndex;
+    partyMember.fusionShiny = ally.shiny;
+    partyMember.fusionVariant = ally.variant;
+    partyMember.fusionGender = ally.gender;
+    partyMember.fusionLuck = ally.luck;
+
+    const defStat = partyMember.getStat(Stat.DEF);
+    const spDefStat = partyMember.getStat(Stat.SPDEF);
+
+    // Making sure modifier is not applied without holding item
+    const defValue = new Utils.NumberHolder(defStat);
+    partyMember.scene.applyModifiers(EvolutionStatBoosterModifier, true, partyMember, Stat.DEF, defValue);
+    const spDefValue = new Utils.NumberHolder(spDefStat);
+    partyMember.scene.applyModifiers(EvolutionStatBoosterModifier, true, partyMember, Stat.SPDEF, spDefValue);
+
+    expect(defValue.value / defStat).toBe(1);
+    expect(spDefValue.value / spDefStat).toBe(1);
+
+    // Giving Eviolite to party member and testing if it applies
+    partyMember.scene.addModifier(modifierTypes.EVIOLITE().newModifier(partyMember), true);
+    partyMember.scene.applyModifiers(EvolutionStatBoosterModifier, true, partyMember, Stat.DEF, defValue);
+    partyMember.scene.applyModifiers(EvolutionStatBoosterModifier, true, partyMember, Stat.SPDEF, spDefValue);
+
+    expect(defValue.value / defStat).toBe(1);
+    expect(spDefValue.value / spDefStat).toBe(1);
+  }, 20000);
+});