public function testConstruct()
 {
     $field = new FieldExpression('test');
     $order = new OrderExpression($field);
     $this->assertEquals($field, $order->getExpression());
     $this->assertEquals(OrderExpression::DIRECTION_ASC, $order->getDirection());
 }
 /**
  * Create the SQL of a order expression
  * @param zibo\library\database\manipulation\expression\OrderExpression $order
  * @return string SQL of the order expression
  */
 protected function parseOrderExpression(OrderExpression $order)
 {
     return $this->parseExpression($order->getExpression(), true) . ' ' . $order->getDirection();
 }