Doctrine\MongoDB\Query\Expr::sort PHP Метод

    public function sort($fieldName, $order = null)
    {
        $fields = is_array($fieldName) ? $fieldName : [$fieldName => $order];
        foreach ($fields as $fieldName => $order) {
            if (is_string($order)) {
                $order = strtolower($order) === 'asc' ? 1 : -1;
            }
            $sort[$fieldName] = (int) $order;
        }
        return $this->operator('$sort', $sort);
    }

 public function testPushWithExpressionShouldEnsureEachOperatorAppearsFirst()
 {
     $expr = new Expr();
     $innerExpr = new Expr();
     $innerExpr->sort('x', 1)->slice(-2)->each(array(array('x' => 1), array('x' => 2)));
     $expectedNewObj = array('$push' => array('a' => array('$each' => array(array('x' => 1), array('x' => 2)), '$sort' => array('x' => 1), '$slice' => -2)));
     $this->assertSame($expr, $expr->field('a')->push($innerExpr));
     $this->assertSame($expectedNewObj, $expr->getNewObj());
 }