Having just checked out the repo I ran the tests and received:

$ nosetests test_bitly_api.py
EE..

ERROR: test_bitly_api.testApi
...
raise BitlyError(data.get('status_code', 500), data.get('status_txt', 'UNKNOWN_ERROR'))
BitlyError: RATE_LIMIT_EXCEEDED
...
ERROR: test_bitly_api.testExpand
...
raise BitlyError(data.get('status_code', 500), data.get('status_txt', 'UNKNOWN_ERROR'))
BitlyError: RATE_LIMIT_EXCEEDED

Can your API key be whitelisted to allow these tests to pass, or perhaps you should force us to use our own API key (environment variable? local config file?), such that all the tests pass on a clean checkout?