How to test logstash Marker in Junit

Question

I have to create a Junit test for my class logging

Map<String, Object> mapMarker = new HashMap<>();
mapMarker.put("input_source", "test_input_source");
LogstashMarker logstashMarker = Markers.appendEntries(mapMarker);
log.info(logstashMarker, "logging test OK");

What can I do to show that in my log, there is the Marker "input_source" with the value "test_input_source". (there is no problem with the log message, the Marker isn't in the message log) ?

I try using ILoggingEvent to catch the log, but I can't get the value of my Marker "input_source" from this.
Updated : I use LogstashEncoderto encode the log, than ObjectMapper to parse this log to a map. With this way, i can get the marker in the map.

Thanks

Answer 1

You can configure your logger like so for testing purposes:

// src/test/resources/logback-test.xml
<configuration>
  <appender name="LIST" class="ch.qos.logback.core.read.ListAppender"/>
  <root level="info">
    <appender-ref ref="LIST"/>
  </root>
</configuration>

and then stream through the LIST appender for events:

private void assertLogsDoNotContain() {
    Logger logger = (Logger) LoggerFactory.getLogger(org.slf4j.Logger.ROOT_LOGGER_NAME);
    ListAppender<ILoggingEvent> loggingEventStream = (ListAppender<ILoggingEvent>) logger.getAppender("LIST");
    assertThat(loggingEventStream.list.stream()
        .filter(x -> x.toString().contains("logging test OK"))
        .filter(y -> y.getMarker().contains(Markers.append("input_source", "test_input_source")))
    ).isNotEmpty();
}