Yet another way to testing logging in application which use SLF4J.
- this binding support for easy create 
Mockitomock forLogger - call to 
Loggercan be delegated to instance ofSimpleLogger, so we can create standardsimplelogger.properties - support for testing and mocking 
MDC - light transitive dependencies - only 
slf4j-apiandmockito-core - support testing in parallel in multi thread
 - all the Magic are done by 
Mockitoplugins, so you don't need to directly use class from this library - ease use
 
Add dependency to your project:
For SLF4J 1.7.x
<dependencies>
    <dependency>
        <groupId>org.simplify4u</groupId>
        <artifactId>slf4j-mock</artifactId>
        <version><!-- check relases page --></version>  
        <scope>test</scope>        
    </dependency>
<dependencies>
For SLF4J 2.x
<dependencies>
    <dependency>
        <groupId>org.simplify4u</groupId>
        <artifactId>slf4j2-mock</artifactId>
        <version><!-- check relases page --></version>  
        <scope>test</scope>        
    </dependency>
<dependencies>
Please remember, that you can only have one SLF4J binding or provider on classpath,
in the most case you must replace org.slf4j:slf4j-simple by org.simplify4u:slf4j-mock.
Write test:
class MyTest {
    @Mock
    Logger logger;
    @InjectMocks
    Example sut;
    @Test
    public void logInfoShouldBeLogged() {
        // when
        sut.methodWithLogInfo(INFO_TEST_MESSAGE);
        // then
        verify(logger).info(INFO_TEST_MESSAGE);
        verifyNoMoreInteractions(logger);
    }
}
More information and examples you can find on site: