Yet another way to testing logging in application which use SLF4J.

• this binding support for easy create Mockito mock for Logger
• call to Logger can be delegated to instance of SimpleLogger, so we can create standard simplelogger.properties
• support for testing and mocking MDC
• light transitive dependencies - only slf4j-api and mockito-core
• support testing in parallel in multi thread
• all the Magic are done by Mockito plugins, so you don't need to directly use class from this library
• ease use

Add dependency to your project:

<dependencies>
    <dependency>
        <groupId>org.simplify4u</groupId>
        <artifactId>slf4j-mock</artifactId>
        <version><!-- check relases page --><version>  
        <scope>test</scope>        
    </dependency>
<dependencies>

Please remember, that you can only have one SLF4J binding 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:

https://www.simplify4u.org/slf4j-mock/