public void TestNullDocIdSetIterator() { Directory dir = new RAMDirectory(); IndexWriter writer = new IndexWriter(dir, new KeywordAnalyzer(), true, IndexWriter.MaxFieldLength.LIMITED); writer.Close(); IndexReader reader = IndexReader.Open(dir, true); Filter filter = new AnonymousFilter2(); //final Filter filter = new Filter() { // //@Override // public DocIdSet getDocIdSet(IndexReader reader) { // return new DocIdSet() { // //@Override // public DocIdSetIterator iterator() { // return null; // } // }; // } //}; CachingWrapperFilter cacher = new CachingWrapperFilter(filter); // the caching filter should return the empty set constant Assert.AreSame(DocIdSet.EMPTY_DOCIDSET, cacher.GetDocIdSet(reader)); reader.Close(); }