JUNIT - Asserting Exceptions

Question

I am using JUNIT 4. I tried to assert the exception using the below code , but it did not work.

@Rule
public ExpectedException thrown = ExpectedException.none();
thrown.expect(ApplicationException.class);

However when I annotated using the below , it worked and test passed.

@Test(expected=ApplicationException.class)

Please let me know if I am missing something.

import org.junit.Rule;
import org.junit.rules.ExpectedException;

public class Test
{

    @Rule
    public ExpectedException exception = ExpectedException.none();

    @org.junit.Test
    public void throwsIllegalArgumentExceptionIfIconIsNull()
    {


        exception.expect(IllegalArgumentException.class);
        toTest();
    }

    private void toTest()
    {
        throw new IllegalArgumentException();
    }
}

Sorry , I realize full veriable example would have been easier to debug. — Punter Vicky, Sep 27 '16 at 16:36

score 4 · Accepted Answer · answered Sep 27 '16 at 16:17

4

The following code is a minimal example of using the exception rule.

public class Test
{

    @Rule
    public ExpectedException exception = ExpectedException.none();

    @org.junit.Test
    public void throwsIllegalArgumentExceptionIfIconIsNull()
    {
        exception.expect(IllegalArgumentException.class);
        toTest();
    }

    private void toTest()
    {
        throw new IllegalArgumentException();
    }
}

Please see also (Wiki entry about rules)

answered Sep 27 '16 at 16:17

Dangermouse

290
1
3
11

Thank You!! I had placed exception.expect(IllegalArgumentException.class); below toTest() and realize the folly now! – Punter Vicky Sep 27 '16 at 16:35

score 1 · Answer 2 · answered Sep 27 '16 at 16:52

1

An alternative approach (and simpler?) to using a Rule is to place a fail() after the call where you expect the exception to occur. If you get the exception, the test method succeeds (you never reach the fail). If you don't get the exception and you reach the fail() statement, then the test fails.

answered Sep 27 '16 at 16:52

Kevin Hooke

2,583
2
19
33

I was looking to validate the exception type , code and message as well. Is it possible with the approach that you had suggested? Thanks. – Punter Vicky Sep 27 '16 at 17:20
See the linked duplicate question/answer - this has what you're looking for – Kevin Hooke Sep 27 '16 at 20:35

JUNIT - Asserting Exceptions

2 Answers2