[Balance] Enemy trainer Pokemon will have friendship based on the wave

https://github.com/pagefaultgames/pokerogue/pull/6617

The formula is `round(max friendship * (current wave / 200))`
where the max friendship value a Pokemon can have is `255`
and `current wave / 200` represents a % value based on
how far in the game you are

src/field/pokemon.ts

@@ -6390,6 +6390,7 @@ export class EnemyPokemon extends Pokemon {
           ivs.push(randSeedIntRange(Math.floor(waveIndex / 10), 31));
         }
         this.ivs = ivs;
+        this.friendship = Math.round(255 * (waveIndex / 200));
       }
     }
 

test/field/pokemon.test.ts

@@ -203,14 +203,29 @@ describe("Spec - Pokemon", () => {
     "should set minimum IVs for enemy trainer pokemon based on wave (%i)",
     async wave => {
       game.override.startingWave(wave);
-      await game.classicMode.startBattle([SpeciesId.FEEBAS]);
-      const { waveIndex } = game.scene.currentBattle;
+      await game.classicMode.runToSummon([SpeciesId.FEEBAS]);
 
-      for (const pokemon of game.scene.getEnemyParty()) {
-        for (const index in pokemon.ivs) {
-          expect(pokemon.ivs[index]).toBeGreaterThanOrEqual(Math.floor(waveIndex / 10));
+      for (const pokemon of game.field.getEnemyParty()) {
+        for (const iv of pokemon.ivs) {
+          expect(iv).toBeGreaterThanOrEqual(Math.floor(wave / 10));
         }
       }
     },
   );
+
+  it.each([
+    { wave: 5, friendship: 6 },
+    { wave: 25, friendship: 32 },
+    { wave: 55, friendship: 70 },
+    { wave: 95, friendship: 121 },
+    { wave: 145, friendship: 185 },
+    { wave: 195, friendship: 249 },
+  ])("should set friendship for enemy trainer pokemon based on wave ($wave)", async ({ wave, friendship }) => {
+    game.override.startingWave(wave);
+    await game.classicMode.runToSummon([SpeciesId.FEEBAS]);
+
+    for (const pokemon of game.field.getEnemyParty()) {
+      expect(pokemon.friendship).toBe(friendship);
+    }
+  });
 });

test/test-utils/helpers/field-helper.ts

@@ -44,6 +44,26 @@ export class FieldHelper extends GameManagerHelper {
     return pokemon!;
   }
 
+  /**
+   * Passthrough for {@linkcode globalScene.getPlayerParty} that adds a check that the party contains at least 1 pokemon.
+   * @returns The enemy party
+   */
+  public getPlayerParty(): PlayerPokemon[] {
+    const party = this.game.scene.getPlayerParty();
+    expect(party.length).toBeGreaterThan(0);
+    return party;
+  }
+
+  /**
+   * Passthrough for {@linkcode globalScene.getEnemyParty} that adds a check that the party contains at least 1 pokemon.
+   * @returns The enemy party
+   */
+  public getEnemyParty(): EnemyPokemon[] {
+    const party = this.game.scene.getEnemyParty();
+    expect(party.length).toBeGreaterThan(0);
+    return party;
+  }
+
   /**
    * Helper function to return all on-field {@linkcode Pokemon} in speed order (fastest first).
    * @param indices - Whether to only return {@linkcode BattlerIndex}es instead of full Pokemon objects