code: @Test public void nested(){
    Throwable nestedException=makeNestedException(2);
    nestedException.printStackTrace(printWriter);
    ILoggingEvent le=createLoggingEvent(nestedException);
    String result=converter.convert(le);
    assertThat(result).startsWith("java.lang.Exception: nesting level=0");
    assertThat(positionOf("nesting level=0").in(result)).isLessThan(positionOf("nesting level =1").in(result));
    assertThat(positionOf("nesting level =1").in(result)).isLessThan(positionOf("nesting level =2").in(result));
  }
  