atk4\data\tests\ReferenceSQLTest::testLink2 PHP Method

    public function testLink2()
    {
        $db = new Persistence_SQL($this->db->connection);
        $u = (new Model($db, 'user'))->addFields(['name', 'currency_code']);
        $c = (new Model($db, 'currency'))->addFields(['code', 'name']);
        $u->hasMany('cur', [$c, 'our_field' => 'currency_code', 'their_field' => 'code']);
        $this->assertEquals('select `id`,`code`,`name` from `currency` where `code` = `user`.`currency_code`', $u->refLink('cur')->action('select')->render());
    }