public function testsumSprintStats()
 {
     $stats = new SprintStats();
     $viewer = $this->generateNewTestUser();
     $timezone = $stats->setTimezone($viewer);
     $date = new DateTime();
     $now = $date->format('U');
     $end = $now + $this->week_interval * 2;
     $timeseries = $stats->buildDateArray($now, $end, $timezone);
     $dates = $stats->sumSprintStats($timeseries);
     $this->assertInstanceOf('BurndownDataDate', array_pop($dates));
 }