@Test
public void testClearParagraphOutput() throws IOException, SchedulerException{

  Note note = notebook.createNote(null);
  Paragraph p1 = note.addParagraph();
  Map config = p1.getConfig();
  config.put("enabled", true);
  p1.setConfig(config);
  p1.setText("hello world");
  note.run(p1.getId());
  while(p1.isTerminated()==false || p1.getResult()==null) Thread.yield();
  assertEquals("repl1: hello world", p1.getResult().message());
  // clear paragraph output/result
  note.clearParagraphOutput(p1.getId());
  assertNull(p1.getResult());
}