@Test
public void testError() throws Exception {

    Logger logger = Mockito.mock(Logger.class);
    when(logger.isErrorEnabled()).thenReturn(true);
    LogHelper.error(logger, "error");
    verify(logger).error("error");
    Throwable t = new RuntimeException();
    LogHelper.error(logger, t);
    verify(logger).error(t);
    LogHelper.error(logger, "error", t);
    verify(logger).error("error", t);
}