ILoggingEvent event = mockBasicILoggingEvent(Level.ERROR);
when(event.getLoggerName()).thenReturn(FastDateFormat.class.getCanonicalName());
when(event.getTimeStamp()).thenReturn(timestamp);
encoder.setFieldNames(new ShortenedFieldNames());
encoder.setShortenedLoggerNameLength(length);
encoder.doEncode(event);
closeQuietly(outputStream);
JsonNode node = MAPPER.readTree(outputStream.toByteArray());