AbstractRuleBucket { public int size() { return rules.size(); }  int size(); Collection<T> getAll(); Set<String> getIds(); T getById(String id); List<T> match(String pattern); void add(B bucket);  }
@Test public void sizeOfBucketIsZeroIfThereAreNotConcepts() { assertThat(bucket.size()).isEqualTo(0); }