public function testIntersectAcceptsCallback()
{
$xao = new XArray([1, 22, 'foo' => 'bar', 'x' => 'y', 4]);
$test = new CallbackTestMethods();
$obj = $xao->intersect(['xxx', 18], [$test, 'length_compare']);
$this->assertEquals([1 => 22, 'foo' => 'bar'], (array) $obj);
}