modifyClone(); Assert::type(DateTime::class, $dolly); Assert::notSame($date, $dolly); Assert::same((string) $date, (string) $dolly); $dolly2 = $date->modifyClone('+1 hour'); Assert::type(DateTime::class, $dolly2); Assert::notSame($date, $dolly2); Assert::notSame((string) $date, (string) $dolly2);