AbstractRuleBucket { public Set<String> getIds() { return Collections.unmodifiableSet(rules.keySet()); }  int size(); Collection<T> getAll(); Set<String> getIds(); T getById(String id); List<T> match(String pattern); void add(B bucket);  }
@Test public void getConceptsIdsReturnsEmptySetIfThereAreNoConceptsInTheBucket() { assertThat(bucket.getIds(), empty()); }