public function testGenerateSingle()
{
$now = strtotime('2/13/2014');
$repetition = new Duration();
$repetition->setStartDate(date('Y-m-d H:i:s', $now));
$repetition->setEndDate(date('Y-m-d H:i:s', $now + 86400));
$occurrences = $repetition->activeRangesBetween($now, strtotime('+5 years', $now));
$this->assertNotEmpty($occurrences);
$this->assertEquals(1, count($occurrences));
$occurrence = $occurrences[0];
$this->assertEquals(strtotime($repetition->getStartDate()), $occurrence[0]);
$this->assertEquals(strtotime($repetition->getEndDate()), $occurrence[1]);
$repetition->setEndDate(null);
$this->assertTrue($repetition->isActive($now));
}