LogHelper { public static void debug(Logger logger, String msg) { if (logger == null) { return; } if (logger.isDebugEnabled()) { logger.debug(msg); } } private  LogHelper(); static void trace(Logger logger, String msg); static void trace(Logger logger, Throwable throwable); static void trace(Logger logger, String msg, Throwable e); static void debug(Logger logger, String msg); static void debug(Logger logger, Throwable e); static void debug(Logger logger, String msg, Throwable e); static void info(Logger logger, String msg); static void info(Logger logger, Throwable e); static void info(Logger logger, String msg, Throwable e); static void warn(Logger logger, String msg, Throwable e); static void warn(Logger logger, String msg); static void warn(Logger logger, Throwable e); static void error(Logger logger, Throwable e); static void error(Logger logger, String msg); static void error(Logger logger, String msg, Throwable e);  }
@Test public void testDebug() throws Exception { Logger logger = Mockito.mock(Logger.class); when(logger.isDebugEnabled()).thenReturn(true); LogHelper.debug(logger, "debug"); verify(logger).debug("debug"); Throwable t = new RuntimeException(); LogHelper.debug(logger, t); verify(logger).debug(t); LogHelper.debug(logger, "debug", t); verify(logger).debug("debug", t); }