public function testJoinDereferenced()
 {
     $this->assertEquals('{!join from=$deref_1 to=$deref_2}', $this->helper->join('manu_id', 'id', true));
     $this->assertEquals(array('deref_1' => 'manu_id', 'deref_2' => 'id'), $this->query->getParams());
 }