JUnit right way of test expected exceptions

Question

Hello guys I was wondering if this way of testing my exception is ok, i have this exception i need to throw in the second test annotation, im receiving as result a red evil

Answer 1

There is 3 most common ways to test expected exception:

First one is the most common way, but you can test only the type of expected exception with it. This test will fail if ExceptionType won't be thrown:

@Test(expected = ExceptionType.class)
public void testSomething(){
    sut.doSomething();
}

Also you cannot specify the failure message using this approach

The better option is to use ExpectedException JUnit @Rule. Here you can assert much more for expected exception

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

@Test
public void testSomething(){
    thrown.expect(ExceptionType.class);
    thrown.expectMessage("Error message");
    thrown.expectCause(is(new CauseOfExeption()));
    thrown.reportMissingExceptionWithMessage("Exception expected"); 
    //any other expectations
    sut.doSomething();
}

The third option will allow you to do the same as with using ExpectedException @Rule, but all the assertion should be written manually. However the advantage of this method is that you can use any custom assertion and any assertion library that you want:

@Test
public void testSomething(){
    try{
        sut.doSomething();
        fail("Expected exception");
    } catch(ExceptionType e) {
    //assert ExceptionType e
    } 
}