Question

What do you do with methods that throw exceptions in jUnit tests? As you see the addAnswer method in the Question class may throw a exception. In the shouldFailifTwoAnswerAreCorrect method I want to check if the exception is thrown but in the shouldAddAnswersToQuestion

Should I add throws MultipleAnswersAreCorrectException from the private addAnswerToQuestion method and try/catch in the shouldAddAnswersToQuestion or throw it in that method too?

What do you do when methods throw exception(s) in tests?

public class QuestionTest {

    private Question question;

    @Before
    public void setUp() throws Exception {
        question = new Question("How many wheels are there on a car?", "car.png");
    }

    @Test
    public void shouldAddAnswersToQuestion() {

        addAnswerToQuestion(new Answer("It is 3", false));
        addAnswerToQuestion(new Answer("It is 4", true));
        addAnswerToQuestion(new Answer("It is 5", false));
        addAnswerToQuestion(new Answer("It is 6", false));

        assertEquals(4, question.getAnswers().size());
    }

    @Test(expected = MultipleAnswersAreCorrectException.class)
    public void shouldFailIfTwoAnswersAreCorrect() {

        addAnswerToQuestion(new Answer("It is 3", false));
        addAnswerToQuestion(new Answer("It is 4", true));
        addAnswerToQuestion(new Answer("It is 5", true));
        addAnswerToQuestion(new Answer("It is 6", false));
    }

    private void addAnswerToQuestion(Answer answer) {
        question.addAnswer(answer);
    }
}

Method in Question class

public void addAnswer(Answer answer) throws MultipleAnswersAreCorrectException {

    boolean correctAnswerAdded = false;

    for (Answer element : answers) {
        if (element.getCorrect()) {
            correctAnswerAdded = true;
        }
    }

    if (correctAnswerAdded) {
        throw new MultipleAnswersAreCorrectException();
    } else {
        answers.add(answer);    
    }
}

Answer 1

You have to add throws declaration to addAnswerToQuestion and then either try/catch the exception or use expected attribute or @Test:

@Test(expected=IOException.class)
public void test() {
    // test that should throw IOException to succeed.
}