Evg*_*eev 32
您可以创建自定义appender
public class TestAppender extends AppenderBase<LoggingEvent> {
static List<LoggingEvent> events = new ArrayList<>();
@Override
protected void append(LoggingEvent e) {
events.add(e);
}
}
并配置logback-test.xml以使用它.现在我们可以从测试中检查记录事件:
@Test
public void test() {
...
Assert.assertEquals(1, TestAppender.events.size());
...
}
dav*_*xxx 24
Slf4j API不提供这种方式,但Logback提供了一个简单的解决方案.
您可以使用ListAppender:whitebox logback appender,其中日志条目添加public List到我们可用于进行断言的字段中.
这是一个简单的例子.
Foo类:
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
public class Foo {
static final Logger LOGGER = LoggerFactory.getLogger(Foo .class);
public void doThat() {
logger.info("start");
//...
logger.info("finish");
}
}
FooTest类:
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.core.read.ListAppender;
public class FooTest {
@Test
void doThat() throws Exception {
// get Logback Logger
Logger fooLogger = (Logger) LoggerFactory.getLogger(Foo.class);
// create and start a ListAppender
ListAppender<ILoggingEvent> listAppender = new ListAppender<>();
listAppender.start();
// add the appender to the logger
fooLogger.addAppender(listAppender);
// call method under test
Foo foo = new Foo();
foo.doThat();
// JUnit assertions
List<ILoggingEvent> logsList = listAppender.list;
assertEquals("start", logsList.get(0)
.getMessage());
assertEquals(Level.INFO, logsList.get(0)
.getLevel());
assertEquals("finish", logsList.get(1)
.getMessage());
assertEquals(Level.INFO, logsList.get(1)
.getLevel());
}
}
您还可以使用Matcher /断言库作为AssertJ或Hamcrest.
使用AssertJ,它将是:
import org.assertj.core.api.Assertions;
Assertions.assertThat(listAppender.list)
.extracting(ILoggingEvent::getMessage, ILoggingEvent::getLevel)
.containsExactly(Tuple.tuple("start", Level.INFO), Tuple.tuple("finish", Level.INFO));
Ole*_*ski 12
您可以使用http://projects.lidalia.org.uk/slf4j-test/中的 slf4j-test .它通过它自己的slf4j api实现来替换整个logback slf4j实现,并提供一个api来对记录事件进行断言.
例:
<build>
<plugins>
<plugin>
<artifactId>maven-surefire-plugin</artifactId>
<configuration>
<classpathDependencyExcludes>
<classpathDependencyExcludes>ch.qos.logback:logback-classic</classpathDependencyExcludes>
</classpathDependencyExcludes>
</configuration>
</plugin>
</plugins>
</build>
public class Slf4jUser {
private static final Logger logger = LoggerFactory.getLogger(Slf4jUser.class);
public void aMethodThatLogs() {
logger.info("Hello World!");
}
}
public class Slf4jUserTest {
Slf4jUser slf4jUser = new Slf4jUser();
TestLogger logger = TestLoggerFactory.getTestLogger(Slf4jUser.class);
@Test
public void aMethodThatLogsLogsAsExpected() {
slf4jUser.aMethodThatLogs();
assertThat(logger.getLoggingEvents(), is(asList(info("Hello World!"))));
}
@After
public void clearLoggers() {
TestLoggerFactory.clear();
}
}
epo*_*pox 12
private ListAppender<ILoggingEvent> logWatcher;
@BeforeEach
void setup() {
this.logWatcher = new ListAppender<>();
this.logWatcher.start();
((Logger) LoggerFactory.getLogger(MyClass.class)).addAppender(this.logWatcher);
}
@Test
void myMethod_logs2Messages() {
...
int logSize = logWatcher.list.size();
assertThat(logWatcher.list.get(logSize - 2).getFormattedMessage()).contains("EXPECTED MSG 1");
assertThat(logWatcher.list.get(logSize - 1).getFormattedMessage()).contains("EXPECTED MSG 2");
}
归功于：@davidxxx 的回答。看到它import ch.qos.logback...的细节：/sf/answers/3656074061/
一个简单的解决方案可能是用 Mockito 模拟附加程序（例如）
@Slf4j
class MyClass {
public void doSomething() {
log.info("I'm on it!");
}
}
import static org.hamcrest.MatcherAssert.assertThat;
import static org.hamcrest.Matchers.containsString;
import static org.hamcrest.Matchers.is;
import static org.mockito.Mockito.verify;
@RunWith(MockitoJUnitRunner.class)
public class MyClassTest {
@Mock private Appender<ILoggingEvent> mockAppender;
private MyClass sut = new MyClass();
@Before
public void setUp() {
Logger logger = (Logger) LoggerFactory.getLogger(MyClass.class.getName());
logger.addAppender(mockAppender);
}
@Test
public void shouldLogInCaseOfError() {
sut.doSomething();
verify(mockAppender).doAppend(ArgumentMatchers.argThat(argument -> {
assertThat(argument.getMessage(), containsString("I'm on it!"));
assertThat(argument.getLevel(), is(Level.INFO));
return true;
}));
}
}
注意：我使用断言而不是返回，false因为它使代码和（可能的）错误更易于阅读，但如果您有多次验证，它将不起作用。在这种情况下，您需要返回boolean指示该值是否符合预期。
尽管创建自定义 logback appender 是一个很好的解决方案，但这只是第一步，您最终将最终开发/重新发明slf4j-test，如果您更进一步：spf4j-slf4j-test或其他我不知道的框架还不知道。
您最终将需要担心您在内存中保留了多少事件，在记录错误（而不是断言）时使单元测试失败，在测试失败时使调试日志可用，等等......
免责声明：我是 spf4j-slf4j-test 的作者，我写这个后端是为了能够更好地测试spf4j，这是查看如何使用 spf4j-slf4j-test 的示例的好地方。我获得的主要优势之一是减少了我的构建输出（这在 Travis 中受到限制），同时在发生故障时仍然拥有我需要的所有细节。
我会推荐一个简单的、可重用的间谍实现，它可以作为 JUnit 规则包含在测试中：
public final class LogSpy extends ExternalResource {
private Logger logger;
private ListAppender<ILoggingEvent> appender;
@Override
protected void before() {
appender = new ListAppender<>();
logger = (Logger) LoggerFactory.getLogger(Logger.ROOT_LOGGER_NAME); // cast from facade (SLF4J) to implementation class (logback)
logger.addAppender(appender);
appender.start();
}
@Override
protected void after() {
logger.detachAppender(appender);
}
public List<ILoggingEvent> getEvents() {
if (appender == null) {
throw new UnexpectedTestError("LogSpy needs to be annotated with @Rule");
}
return appender.list;
}
}
在您的测试中，您将通过以下方式激活间谍：
@Rule
public LogSpy log = new LogSpy();
调用log.getEvents()（或其他自定义方法）以检查记录的事件。
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