svelte/test/compiler/events-lifecycle/_config.js

import * as assert from 'assert';

export default {
	test ( component ) {
		let count = 0;

		component.on( 'teardown', function () {
			assert.equal( this, component );
			count += 1;
		});

		component.teardown();
		assert.equal( count, 1 );
	}
};