/**
* Subtract a duration to this one. If $duration is greather than or equal to
* the current duration, a duration of 0 seconds is returned.
*
* For instance P2S - P1S = P1S
*/
public function sub(QtiDuration $duration)
{
if ($duration->longerThanOrEquals($this) === true) {
$this->setInterval(new DateInterval('PT0S'));
} else {
$refStrDate = '@0';
$tz = new DateTimeZone(self::TIMEZONE);
$d1 = new DateTime($refStrDate, $tz);
$d2 = new DateTime($refStrDate, $tz);
$d1->add(new DateInterval($this->__toString()));
$d2->add(new DateInterval($duration->__toString()));
$interval = $d1->diff($d2);
$this->setInterval($interval);
}
}
/**
* @dataProvider longerThanOrEqualsProvider
*
* @param Duration $duration1
* @param Duration $duration2
* @param boolean $expected
*/
public function testLongerThanOrEquals(QtiDuration $duration1, QtiDuration $duration2, $expected)
{
$this->assertSame($expected, $duration1->longerThanOrEquals($duration2));
}
