Elastica\Aggregation\Filter::setFilter PHP Method

    public function setFilter(AbstractQuery $filter)
    {
        return $this->setParam('filter', $filter);
    }

 public function testFilterAggregation()
 {
     $agg = new Filter("filter");
     $agg->setFilter(new Term(array("color" => "blue")));
     $avg = new Avg("price");
     $avg->setField("price");
     $agg->addAggregation($avg);
     $query = new Query();
     $query->addAggregation($agg);
     $results = $this->_index->search($query)->getAggregation("filter");
     $results = $results['price']['value'];
     $this->assertEquals((5 + 8) / 2.0, $results);
 }