public String getFormattedMessage() {
    if (formattedMessage != null) {
      return formattedMessage;
    }
    if (argumentArray != null) {
      formattedMessage = MessageFormatter.arrayFormat(message, argumentArray)
              .getMessage();
    } else {
      formattedMessage = message;
    }

    return formattedMessage;
  }
@Test
  public void testFormattingTwoArg() {
    String message = "{}-{}";
    Throwable throwable = null;
    Object[] argArray = new Object[] {12, 13};
    LoggingEvent event = new LoggingEvent("", logger, Level.INFO, message, throwable, argArray);

    assertNull(event.formattedMessage);
    assertEquals("12-13", event.getFormattedMessage());
  }