test(object-ref-spec): add toHaveBeenCalledWith tests for get and update functions

- add toHaveBeenCalledWith to test `get` method
- add test when invoking `get` without fields in the passed `options` parameter to return rejected promise
- add toHaveBeenCalledWith to `update`method spec
- add tests when invoking 'update` without ops in the passed `options` parameter to return rejected promise
- add toHaveBeenCalledWith to `delete` method spec

closes REALLY-78
`result = user.get(options)` why you are assuming it'll throw exception here `You should pass array or nothing for fields option` user is passing nothing for `feilds` here