# This is the "mockator":
def _mock_requests_method(responses, url, *dummy1, **dummy2):
    """Check the URL and return the expected response."""
    if url not in responses:
        raise AssertionError('URL doesnt exist: {}', url)
    (status, text) = responses[url]
    response = Response()
    response.status_code = status
    response.raw = StringIO.StringIO(text)
    return response


# This is how you mock Requests in the test:
@patch('yourmodule.requests.get')    # same for posts
def test_something(self, mocked_get):
    mocked_get.side_effect = functools.partial(_mock_requests_method,
        {'some/url': (200, 'Response for some/url'),
         'some/other/url': (404, 'Response for some/other/url')}
    )
    # and the rest of your test.