def test_login(self):
mock_response = mock.Mock()
mock_response.json.return_value = {'access_token': 'abc123'}
mock_session = mock.Mock()
mock_session.get.return_value = mock_response
test_session = Session('client', 'client_secret', mock_session)
test_session.login('user', 'user_secret')
mock_session.get.assert_called_once()
mock_session.headers.update.assert_called_once_with({'Authorization': 'Bearer abc123'})
