LogEvent event = Log4jLogEvent.newBuilder()
                .setLoggerName("test.logger")
                .setLevel(Level.ERROR)
                .setMessage(new SimpleMessage("test message"))
                .setLoggerFqcn("test.class")
                .setThreadName("test-thread")
                .build();

        LogEvent result = policy.rewrite(event);

        assertEquals(Level.WARN, result.getLevel());