public function testDrop()
{
$this->assertEquals([7, 8, 9], drop([1, 2, 3, 4, 5, 6, 7, 8, 9], 6));
$this->assertEquals([7, 8, 9], drop(new \ArrayIterator([1, 2, 3, 4, 5, 6, 7, 8, 9]), 6));
$this->assertEquals([1, 2, 3, 4, 5, 6, 7, 8, 9], drop([1, 2, 3, 4, 5, 6, 7, 8, 9], 0));
$this->assertEquals([], drop([], 3));
$this->assertEquals([7, 8, 9], call_user_func(drop, [1, 2, 3, 4, 5, 6, 7, 8, 9], 6));
$this->assertEquals('\\nspl\\a\\drop', drop);
}