public function testQuerySeries()
 {
     // query in StudyInstanceUID
     $server_ip = '134.174.12.21';
     $server_port = 104;
     $user_aetitle = 'FNNDSC-CHRISDEV';
     $pacs_siiud = new PACS($server_ip, $server_port, $user_aetitle);
     $pacs_siiud->addParameter('StudyInstanceUID', '1.2.840.113845.11.1000000001785349915.20120409172607.5904669');
     $result_siiud = $pacs_siiud->querySeries();
     // should return 34 results
     $this->assertTrue(count($result_siiud['StudyInstanceUID']) == 34);
     // query on unknown parameter
     $pacs_fake = new PACS($server_ip, $server_port, $user_aetitle);
     $pacs_fake->addParameter('FakeParameter', 'IAmAFakeParameter');
     $result_fake = $pacs_fake->querySeries();
     // should return an empty array
     $this->assertTrue($result_fake == null);
     // we add not enough parameter (no user AE Title)
     $pacs_not_enough = new PACS($server_ip, $server_port);
     $pacs_not_enough->addParameter('PatientID', 4562009);
     $result_not_enough = $pacs_not_enough->querySeries();
     // should return null
     $this->assertTrue($result_not_enough == null);
 }