Sokil\Mongo\AggregatePipelinesTest::testAggregate_ExplainOption PHP Method

    public function testAggregate_ExplainOption()
    {
        $this->collection->createDocument(array('param' => 1))->save();
        $this->collection->createDocument(array('param' => 2))->save();
        $this->collection->createDocument(array('param' => 3))->save();
        $this->collection->createDocument(array('param' => 4))->save();
        $pipeline = $this->collection->createAggregator()->match(array('param' => array('$gte' => 2)))->group(array('_id' => 0, 'sum' => array('$sum' => '$param')))->explain();
        try {
            $explain = $this->collection->aggregate($pipeline);
            $this->assertArrayHasKey('$cursor', $explain['0']);
            $this->assertArrayHasKey('$group', $explain['1']);
        } catch (\Exception $e) {
            $this->assertEquals('Explain of aggregation implemented only from 2.6.0', $e->getMessage());
        }
    }