@Test
public void getFacets_never_return_null()
{

    List<Plugin> plugins = new ArrayList<>();
    OneFacetPlugin oneFacetPlugin = new OneFacetPlugin();
    plugins.add(oneFacetPlugin);
    FacetRegistry registry = new FacetRegistry(plugins);
    List<Facet2> facet2s = registry.getFacets(Facet2.class);
    Assertions.assertThat(facet2s).isNotNull();
    Assertions.assertThat(facet2s).isEmpty();
}