'Test `get_score` is working for additional answers.'

def test_additional_answer_get_score(self):

    problem = self.build_problem(answer='100', additional_answers={'1': ''})
    responder = problem.responders.values()[0]
    new_cmap = responder.get_score({'1_2_1': '100'})
    self.assertEqual(new_cmap.get_correctness('1_2_1'), 'correct')
    new_cmap = responder.get_score({'1_2_1': '1'})
    self.assertEqual(new_cmap.get_correctness('1_2_1'), 'correct')
    new_cmap = responder.get_score({'1_2_1': '2'})
    self.assertEqual(new_cmap.get_correctness('1_2_1'), 'incorrect')
