@Test //(expected=IllegalStateException.class)
public void canNotSearchBeforeIndexing() {

  //given NO notebookIndex.index() was called
  //when
  List<Map<String, String>> result = notebookIndex.query("anything");
  //then
  assertThat(result).isEmpty();
  //assert logs were printed
  //"ERROR org.apache.zeppelin.search.SearchService:97 - Failed to open index dir RAMDirectory"
}