public function testAddAndSubtractReturnCorrectFormat()
{
$testTimeValue = new TimeValue('01:30', 'H:i');
$this->assertEquals('02:00:00', $testTimeValue->add(new TimeValue('00:30', 'H:i'))->getTime());
$testTimeValue = new TimeValue('01:30', 'H:i');
$this->assertEquals('01:00:00', $testTimeValue->sub(new TimeValue('00:30', 'H:i'))->getTime());
}
