logger.info("this is an info message with user fields");
String message = appender.getMessages()[0];
Assert.assertTrue("Event is not valid JSON", JSONValue.isValidJsonStrict(message));
Object obj = JSONValue.parse(message);
JSONObject jsonObject = (JSONObject) obj;
Assert.assertTrue("Event does not contain field 'field2'" , jsonObject.containsKey("field2"));
Assert.assertEquals("Event does not contain value 'value2'", "value2", jsonObject.get("field2"));
Assert.assertTrue("Event does not contain field 'field3'" , jsonObject.containsKey("field3"));
Assert.assertEquals("Event does not contain value 'value3'", "value3", jsonObject.get("field3"));
layout.setUserFields(prevUserData);