public String doLayout(ILoggingEvent event) {
    if (!isStarted()) {
      return CoreConstants.EMPTY_STRING;
    }
    return writeLoopOnConverters(event);
  }
@Test
  public void testNopExeptionHandler() {
    pl.setPattern("%nopex %m%n");
    pl.start();
    String val = pl.doLayout(le);
    assertThat(val, not(containsString("java.lang.Exception: Bogus exception")));
  }