public static function Holidays($year, Bundesland $bundesland)
 {
     $easterSunday = PublicHolidays::EasterSunday($year);
     $days['Neujahr'] = new Datum($year . '-01-01');
     $days['Tag der Arbeit'] = new Datum($year . '-05-01');
     $days['Tag der deutschen Einheit'] = new Datum($year . '-10-03');
     $days['1. Weihnachtsfeiertag'] = new Datum($year . '-12-25');
     $days['2. Weihnachtsfeiertag'] = new Datum($year . '-12-26');
     $days['Karfreitag'] = $easterSunday->DateAdd(-2);
     $days['Ostermontag'] = $easterSunday->DateAdd(1);
     $days['Christi Himmelfahrt'] = $easterSunday->DateAdd(39);
     $days['Pfingstmontag'] = $easterSunday->DateAdd(50);
     if (in_array($bundesland->Abbreviation(), array('BW', 'BY', 'ST'))) {
         $days['Hlg. drei Könige'] = new Datum($year . '-01-06');
     }
     if (in_array($bundesland->Abbreviation(), array('BW', 'BY', 'HE', 'NW', 'RP', 'SL'))) {
         $days['Fronleichnam'] = $easterSunday->DateAdd(60);
     }
     if (in_array($bundesland->Abbreviation(), array('SL'))) {
         $days['Maria Himmelfahrt'] = new Datum($year . '-08-15');
     }
     if (in_array($bundesland->Abbreviation(), array('BB', 'MV', 'SN', 'ST', 'TH'))) {
         $days['Reformationstag'] = new Datum($year . '-10-31');
     }
     if (in_array($bundesland->Abbreviation(), array('BW', 'BY', 'NW', 'RP', 'SL'))) {
         $days['Allerheiligen'] = new Datum($year . '-11-01');
     }
     if (in_array($bundesland->Abbreviation(), array('SN'))) {
         $date = new Datum($year . '-11-23');
         $tage = $date->Format('w') + 4;
         if ($tage > 7) {
             $tage -= 7;
         }
         $days['Buß- und Bettag'] = $date->DateAdd(-$tage);
     }
     return $days;
 }
 public function testDateAdd()
 {
     $this->assertEquals(new Datum('2008-09-19'), $this->datum->DateAdd(1));
     $this->assertEquals(new Datum('2008-09-17'), $this->datum->DateAdd(-1));
     $this->assertEquals(new Datum('2008-11-17'), $this->datum->DateAdd(60));
     $datum = new Datum('2009-10-01');
     $this->assertEquals(new Datum('2009-11-01'), $datum->DateAdd(31));
 }