public function __construct($timeString)
 {
     if (is_int($timeString)) {
         $this->inSeconds = $timeString;
         return;
     }
     if (!MultiZeit::isValidTime($timeString)) {
         throw new DatumException("Keine gültige Zeit übergeben: {$timeString}");
     }
     preg_match('/^(-)?([0-9]*):([0-9]{2}):([0-9]{2})$/', $timeString, $match);
     $this->inSeconds = $match[2] * 3600 + $match[3] * 60 + $match[4];
     if ($match[1] > '') {
         $this->inSeconds = -$this->inSeconds;
     }
 }
 public function testIsValidTime()
 {
     $this->assertTrue(MultiZeit::isValidTime("09:18:33"));
     $this->assertFalse(MultiZeit::isValidTime("09:18:77"));
 }