public function testMonthOffsetReturnsExpectedDates() { $this->object->setFirstDate(\DateTime::createFromFormat('Y-m-d', '2014-01-01')); $this->object->setLastDate(\DateTime::createFromFormat('Y-m-d', '2014-03-01')); $this->object->setOpt('interval', 'P1M'); $range = $this->object->getRange(); $this->assertEquals('2014-01-01', $range['2014-01-01']['formatted']); $this->assertEquals('2014-02-01', $range['2014-02-01']['formatted']); $this->assertEquals('2014-03-01', $range['2014-03-01']['formatted']); }