Changed Contact Set from TreeSet to HashSet as Contacts don't need to be ordered and now i don't need to make contacts implement Comparable
Added junit test for addContact method in ContactManager and method containsContact in ContactManager to be used in testing
Added another test for addContact to check whether nullPointerException is thrown when null parameter is given. Test fails as expected
Added another NullPointerException test
Added implementation for addNewContact. 2 tests for checking null pointer exceptions now pass but test for adding correct contact not working.
Added 2nd constructor to ContactImpl that takes notes as well as name. This simplified my addNewContact implementation. However, test is still failing. I think this is probably due to static id number
Made some changes to contactmanagertest which still isn't working