pokemon-showdown/test/simulator/misc/eventemitter.js

var assert = require('assert');
var battle;

describe('Battle#on', function () {
	afterEach(function () {
		battle.destroy();
	});

	it('should allow the addition of one or more event handlers to the battle engine', function () {
		battle = BattleEngine.Battle.construct('battle-1', 'customgame');
		battle.join('p1', 'Guest 1', 1, [{species: 'Pidgeot', ability: 'keeneye', moves: ['bulkup']}]);
		battle.join('p2', 'Guest 2', 1, [{species: 'Talonflame', ability: 'galewings', moves: ['peck']}]);
		battle.commitDecisions(); // Team Preview
		var eventCount = 0;
		var eventCount2 = 0;
		battle.on('Hit', battle.getFormat(), function () {
			eventCount++;
		});
		battle.on('Hit', battle.getFormat(), function () {
			eventCount++;
			eventCount2++;
		});
		battle.on('ModifyDamage', battle.getFormat(), function () {
			return 5;
		});
		battle.commitDecisions();
		assert.strictEqual(eventCount, 4);
		assert.strictEqual(eventCount2, 2);
		assert.strictEqual(battle.p1.active[0].maxhp - battle.p1.active[0].hp, 5);
	});

	it('should support and resolve priorities correctly', function () {
		battle = BattleEngine.Battle.construct('battle-2', 'customgame');
		battle.join('p1', 'Guest 1', 1, [{species: 'Pidgeot', ability: 'keeneye', moves: ['bulkup']}]);
		battle.join('p2', 'Guest 2', 1, [{species: 'Talonflame', ability: 'galewings', moves: ['peck']}]);
		battle.commitDecisions(); // Team Preview
		var eventCount = 0;
		var callback = function (count) {
			return function () {
				assert.strictEqual(eventCount, count);
				eventCount++;
			};
		};
		for (var i = 0; i < 9; i++) {
			battle.on('ModifyDamage', battle.getFormat(), -i, callback(i));
		}
		battle.commitDecisions();
		assert.strictEqual(eventCount, 9);
	});

	it('should throw if a callback is not given for the event handler', function () {
		battle = BattleEngine.Battle.construct('battle-3', 'customgame');
		battle.join('p1', 'Guest 1', 1, [{species: 'Pidgeot', ability: 'keeneye', moves: ['bulkup']}]);
		battle.join('p2', 'Guest 2', 1, [{species: 'Talonflame', ability: 'galewings', moves: ['peck']}]);
		assert.throws(battle.on, TypeError);
		assert.throws(function () {battle.on('Hit');}, TypeError);
		assert.throws(function () {battle.on('Hit', battle.getFormat());}, TypeError);
	});
});