/**
* @depends testGetMonth
*/
public function testSubMonth()
{
$month = new Month(new \DateTime('1987-06-18'));
$month->subMonth();
$this->assertEquals(5, $month->getMonth());
$month->subMonth(0);
$this->assertEquals(5, $month->getMonth());
$month->subMonth(2);
$this->assertEquals(3, $month->getMonth());
}
/**
* Get the distance between this and the given month.
*
* @param Month $month
*
* @return int Number of months
*/
public function getDistance(Month $month)
{
$yd = $this->getYear() - $month->getYear();
$md = $this->getMonth() - $month->getMonth();
return ($yd * 12 + $md) * -1;
}