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

You can use ExpectedException which can provide you more precise information about the exception expected to be thrown with the ability to verify error message, as follows:

import org.junit.Rule;
import org.junit.Test;
import org.junit.rules.ExpectedException;
import org.junit.runner.RunWith;
public class TestClass {

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


    @Test
    public void GTFRICreationTester_shouldFail()  {
        expectedException.expect(TramaConProtolocoloDesconocido.class);
        factory.createLocomotive(weirdProtocol, false, new Date());
    }
}

To expolore more about it, you can refer to the blog written by me here - Expected Exception Rule and Mocking Static Methods – JUnit