How to assert a log using junit

Question

In my service I have conditions that should log an error if it's true. I would like test that in Junit test. How can I do that ?

package com.omb;

@Log4j2
@Component
@RequiredArgsConstructor
public class MyService {

    public void doSomething() {

        log.error("Log an error !");
    }
}

with log4j2 you can also mock an `Appender` similar to https://stackoverflow.com/questions/42096800/log4j2-mock-appender or https://codingcraftsman.wordpress.com/2015/04/28/log4j2-mocking-with-mockito-and-junit/ — zapl, Sep 19 '22 at 16:47
Just add appender. https://stackoverflow.com/a/3717461/13523946 — notAPPP, Sep 19 '22 at 16:48

score 0 · Answer 1 · answered Sep 21 '22 at 08:37

You can also use f.e. Mockito to create mock logger and set the logger using reflection to the service and at the end of the test you can verify if logger was called or not. For setting private property like log for example you can use ReflectionTestUtils class form spring.

How to assert a log using junit

1 Answers1