$this->assertEquals($diff,$row['diff'],"Date difference should be approx. ".$diff." days.",1);
$this->assertEquals('2010-01-01 10:10:11',date('Y-m-d H:i:s',strtotime($row['add_seconds'])),"Adding second should end up on 2010-01-01 10:10:11");
$this->assertEquals('2010-01-01 10:10:09',date('Y-m-d H:i:s',strtotime($row['sub_seconds'])),"Subtracting second should end up on 2010-01-01 10:10:09");
$this->assertEquals('2010-01-01 10:15:10',date('Y-m-d H:i:s',strtotime($row['add_minutes'])),"Adding minutes should end up on 2010-01-01 10:15:10");