def METHOD_NAME(self):
    input_true = '^ is rare'
    input_false = '. is not rare'
    result_true = _add_rare_special_character_score(input_true, 0)
    result_false = _add_rare_special_character_score(input_false, 0)
    assert result_true < 0, 'rare character not detected'
    assert result_false == 0, 'rare character wrongly detected'