I would like to give some feedback about ... predefined data for list the elements shound have 0< |X| < 1000, but one of the test show that one of the list will have zero value inside... i wrote the code that trought exception in this case. Please, or change the predefinitions, or test data. Thank you for help.

From: http://www.checkio.org/mission/non-unique-elements/

HTTP_USER_AGENT:

Mozilla/5.0 (Windows NT 6.1) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/38.0.2125.101 Safari/537.36