function testCompare()
 {
     $d1 = new lmbDateTime('2005-01-01');
     $d2 = new lmbDateTime('2005-01-01');
     $this->assertEqual($d1->compare($d2), 0);
     $this->assertEqual($d1->addYear()->compare($d2), 1);
     $this->assertEqual($d1->compare($d2->addYear(2)), -1);
 }