Como lo señalaron otros, simplemente crea mockAppendery luego crea una LoggingEventinstancia que esencialmente escucha el evento de registro registrado / sucede dentro mockAppender.
Así es como se ve en la prueba:
import org.slf4j.LoggerFactory;
import ch.qos.logback.classic.Level;
import ch.qos.logback.classic.Logger;
import ch.qos.logback.classic.spi.ILoggingEvent;
import ch.qos.logback.classic.spi.LoggingEvent;
import ch.qos.logback.core.Appender;
@RunWith(MockitoJUnitRunner.class)
public class TestLogEvent {
// your Logger
private Logger log = (Logger) LoggerFactory.getLogger(Logger.ROOT_LOGGER_NAME);
// here we mock the appender
@Mock
private Appender<ILoggingEvent> mockAppender;
// Captor is generic-ised with ch.qos.logback.classic.spi.LoggingEvent
@Captor
private ArgumentCaptor<LoggingEvent> captorLoggingEvent;
/**
* set up the test, runs before each test
*/
@Before
public void setUp() {
log.addAppender(mockAppender);
}
/**
* Always have this teardown otherwise we can stuff up our expectations.
* Besides, it's good coding practise
*/
@After
public void teardown() {
log.detachAppender(mockAppender);
}
// Assuming this is your method
public void yourMethod() {
log.info("hello world");
}
@Test
public void testYourLoggingEvent() {
//invoke your method
yourMethod();
// now verify our logging interaction
// essentially appending the event to mockAppender
verify(mockAppender, times(1)).doAppend(captorLoggingEvent.capture());
// Having a generic captor means we don't need to cast
final LoggingEvent loggingEvent = captorLoggingEvent.getValue();
// verify that info log level is called
assertThat(loggingEvent.getLevel(), is(Level.INFO));
// Check the message being logged is correct
assertThat(loggingEvent.getFormattedMessage(), containsString("hello world"));
}
}