Collection<IndexRelationType> getRelations() {
    return relations.values();
  }
@Test
  @UseDataProvider("indexWithAndWithoutRelations")
  public void getRelations_returns_empty_if_no_relation_added(Index index) {
    NewIndex<?> newIndex = new SimplestNewIndex(IndexType.main(index, "foo"), defaultSettingsConfiguration);

    assertThat(newIndex.getRelations()).isEmpty();
  }