commons-logging

Mock loggers for Apache Commons Logging

Apache Commons Logging factory with mock loggers backed by Mockito.

Warning

This library does not support parallel test execution.

How to use

Just put a test dependency to your POM:

<dependency>
    <artifactId>mock-loggers-commons-logging</artifactId>
    <groupId>io.github.vitalijr2.logging</groupId>
    <scope>test</scope>
    <version>1.0.0</version>
</dependency>

The simplest usage example looks like this:

@Test
void helloWorld() {
    var helloService = new HelloService();

    assertDoesNotThrow(helloService::sayHelloWorld);

    verify(LogFactory.getLog(helloService.getClass())).info("Hello World!");
}

See more details at HelloServiceBasicTest.java

Important

Keep in mind that all loggers are initialized only once during the test run.

Therefore, a more complex example cleans the loggers after (or before) each test:

// the static logger instance
private static Log log;

// initialize the mock logger once
@BeforeAll
static void setUpClass() {
    log = LogFactory.getLog(HelloService.class);
}

// clean the mock logger after each test
@AfterEach
void tearDown() {
    clearInvocations(log);
}

// use the mock logger in a test
@DisplayName("Names")
@ParameterizedTest(name = "<{0}>")
@ValueSource(strings = {"John", "Jane"})
void names(String name) {
    var helloService = new HelloService();

    assertDoesNotThrow(() -> helloService.sayHello(name));

    var actualLog = LogFactory.getLog(helloService.getClass());

    verify(actualLog).info("Hello " + name + "!");
    verifyNoMoreInteractions(actualLog);
}

See more details at HelloServiceFullTest.java

To avoid manual cleaning of mock loggers you can use the jUnit extension for automation.

@ExtendWith(MockLoggerExtension.class)
class HelloServiceExtensionTest {

    private static Log log;

    @BeforeAll
    static void setUpClass() {
        log = LogFactory.getLog(HelloService.class);
    }

    @DisplayName("Names")
    @ParameterizedTest(name = "<{0}>")
    @ValueSource(strings = {"John", "Jane"})
    void names(String name) {
        var helloService = new HelloService();

        assertDoesNotThrow(() -> helloService.sayHello(name));

        var actualLog = LogFactory.getLog(helloService.getClass());

        verify(actualLog).info("Hello " + name + "!");
        verifyNoMoreInteractions(actualLog);
    }

}

See more details at HelloServiceExtensionTest.java

Also you can use the annotation for automation.

@MockLoggers
class HelloServiceAnnotationTest {

    private static Log log;

    @BeforeAll
    static void setUpClass() {
        log = LogFactory.getLog(HelloService.class);
    }

    @DisplayName("Names")
    @ParameterizedTest(name = "<{0}>")
    @ValueSource(strings = {"John", "Jane"})
    void names(String name) {
        var helloService = new HelloService();

        assertDoesNotThrow(() -> helloService.sayHello(name));

        var actualLog = LogFactory.getLog(helloService.getClass());

        verify(actualLog).info("Hello " + name + "!");
        verifyNoMoreInteractions(actualLog);
    }

}

See more details at HelloServiceAnnotationTest.java