test empty string-> good
test string of 1 number->good
test string of two numbers with comma between them->good
test string of two numbers with \n between them->good
test few numbers with comma and \n between them->good
test string with one number bigger than 9-->good!
test string with , and than \n -->good
test string with , and then \n and vice verca -->good
throw exception if there is a negative number -> good
finalizing my assignment-> all works good!