public String doLayout(ILoggingEvent event) {
    if (!isStarted()) {
      return CoreConstants.EMPTY_STRING;
    }
    return writeLoopOnConverters(event);
  }
@Test
  public void testCompositePattern() {
    pl.setPattern("%-56(%d %lo{20}) - %m%n");
    pl.start();
    String val = pl.doLayout(getEventObject());
    // 2008-03-18 21:55:54,250 c.q.l.c.pattern.ConverterTest - Some message
    String regex = ISO_REGEX
            + " c.q.l.c.p.ConverterTest          - Some message\\s*";
    assertThat(val, matchesPattern(regex));
  }