/**
  * Add primary coupon to collection
  *
  * @return $this
  */
 public function _initSelect()
 {
     parent::_initSelect();
     $this->getSelect()->joinLeft(['rule_coupons' => $this->getTable('salesrule_coupon')], 'main_table.rule_id = rule_coupons.rule_id AND rule_coupons.is_primary = 1', ['code']);
     return $this;
 }
 public function testAddFieldToFilter()
 {
     $this->_prepareAddFilterStubs();
     $this->abstractCollection->addFieldToFilter('website_ids', []);
 }