SynchronizingSelfLog { public static void warn(String log) { doLog(log, WARN_PREFIX); }  static void error(String log, Throwable e); static void errorWithTraceId(String log, Throwable e); static void error(String log); static void errorWithTraceId(String log, String traceId); static void errorWithTraceId(String log); static void warn(String log); static void info(String log); static void infoWithTraceId(String log); static void flush();  }
@Test public void warn() throws IOException { SynchronizingSelfLog.warn("test warn"); SynchronizingSelfLog.flush(); File log = customFileLog("sync.log"); List<String> logs = FileUtils.readLines(log); assertTrue(logs.toString(), logs.get(0).contains("[WARN]")); assertTrue(logs.toString(), logs.get(0).contains("test warn")); }