/**
* @dataProvider provideTestModifyByDays
*
* @param string $dateStr
* @param string $tzStr
* @param float $byDays
* @param string $expected
*/
public function testModifyByDays($dateStr, $tzStr, $byDays, $expected)
{
$date = new LocalDate($dateStr, $tzStr);
$mod = $date->modifyByDays($byDays);
$this->assertEquals($expected, $mod->format(), 'Modifying a date by days must work');
$this->assertEquals((double) $byDays, $date->diffInDays($mod), 'Diff in days must be correct');
$this->assertEquals((double) $byDays, 0 - $mod->diffInDays($date), 'Diff in days must be correct');
}
