ExpectedException in jUnit?

Question

Is there an equivalent to NUnit's ExpectedException or Assert.Throws<> in jUnit?

Roaring

Answer 1

junit4:

@Test(expected = org.dom4j.DocumentException.class)
void shouldThrowException() {
    getFile(null);
}

junit3:

void testShouldThrowException() {
    try {
      getFile(null);
      fail("Expected Exception DocumentException");
    } catch(DocumentException e) {}
}

Karr

I have updated this answer to include a way to do this in jUnit3 – Lansquenet

The good thing about the "JUnit3" approach is that you can then write one exception-test-case per line, whereas you need five lines for each with the "JUnit4" approach. See my answer for more information: https://mcmap.net/q/1256370/-expectedexception-in-junit – Sherysherye

Actually the answer using ExpectedException by @Maciej is better: https://mcmap.net/q/1256370/-expectedexception-in-junit – Karr

Answer 2

You might also consider taking a look at the ExpectedException class which provides richer exception matching.

https://github.com/junit-team/junit/wiki/Exception-testing

Not only you can match the exception class but also you can apply custom matchers to its message.

Natalee

Answer 3

If you are using Groovy for your junit tests you can use shouldFail.

Here is an example using junit3 style:

void testShouldThrowException() {
    def message = shouldFail(DocumentException) {
        documentService.getFile(null)
    }
    assert message == 'Document could not be saved because it ate the homework.'
}

Lansquenet