public function test_map()
{
$collection = new Collection(array(1, 2, 3, 5));
$mapped = $collection->map(function ($v) {
return $v * 2;
});
$this->assertSame(array(2, 4, 6, 10), $mapped->toArray(), 'All values should be doubled');
$this->assertSame(array(1, 2, 3, 5), $collection->toArray(), 'Original array should remain intact');
}
