Sokil\Mongo\AggregatePipelinesTest::testPipeline_AppendFewGroups PHP Method

    public function testPipeline_AppendFewGroups()
    {
        $pipeline = new Pipeline($this->collection);
        $pipeline->group(array('_id' => '$field1', 'group1' => array('$sum' => '$field2'), 'group2' => array('$sum' => '$field3')));
        $pipeline->group(array('_id' => array('id1' => '$_id', 'id2' => '$group1'), 'field' => array('$sum' => '$group2')));
        $this->assertEquals(array(array('$group' => array('_id' => '$field1', 'group1' => array('$sum' => '$field2'), 'group2' => array('$sum' => '$field3'))), array('$group' => array('_id' => array('id1' => '$_id', 'id2' => '$group1'), 'field' => array('$sum' => '$group2')))), $pipeline->toArray());
    }