/**
* Check if pipeline added as new or appended to previouse on same operator
*/
public function testPipeline_ToString()
{
$pipeline = new Pipeline($this->collection);
// insert new match pipeline
$pipeline->match(array('field1' => 'value1'));
// insert new project pipeline
$pipeline->project(array('field2' => 'value2'));
// insert new match pipeline
$pipeline->match(array('field3' => 'value3'));
// append match pipeline to previous
$pipeline->match(array('field3' => 'value3merged', 'field4' => 'value4'));
// insert new sort pipeline
$pipeline->sort(array('field5' => 'value5'));
// insert new group pipeline
$pipeline->group(array('_id' => '$groupField', 'field6' => array('$sum' => 1)));
$validJson = '[{"$match":{"field1":"value1"}},{"$project":{"field2":"value2"}},{"$match":{"field3":"value3merged","field4":"value4"}},{"$sort":{"field5":"value5"}},{"$group":{"_id":"$groupField","field6":{"$sum":1}}}]';
$this->assertEquals($validJson, $pipeline->__toString());
}
