@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);
}