protected AtomicReaderContext refreshReader() throws Exception {
   if (readerContext != null) {
     readerContext.reader().close();
   }
   AtomicReader reader =
       SlowCompositeReaderWrapper.wrap(topLevelReader = DirectoryReader.open(writer, true));
   readerContext = reader.getContext();
   return readerContext;
 }
  @Before
  public void setup() throws Exception {
    super.setUp();

    // setup field mappers
    strMapper =
        new StringFieldMapper.Builder("str_value")
            .build(new Mapper.BuilderContext(null, new ContentPath(1)));

    lngMapper =
        new LongFieldMapper.Builder("lng_value")
            .build(new Mapper.BuilderContext(null, new ContentPath(1)));

    dblMapper =
        new DoubleFieldMapper.Builder("dbl_value")
            .build(new Mapper.BuilderContext(null, new ContentPath(1)));

    // create index and fielddata service
    ifdService = new IndexFieldDataService(new Index("test"), new DummyCircuitBreakerService());
    MapperService mapperService =
        MapperTestUtils.newMapperService(
            ifdService.index(), ImmutableSettings.Builder.EMPTY_SETTINGS);
    ifdService.setIndexService(new StubIndexService(mapperService));
    writer =
        new IndexWriter(
            new RAMDirectory(),
            new IndexWriterConfig(Lucene.VERSION, new StandardAnalyzer(Lucene.VERSION)));

    int numDocs = 10;
    for (int i = 0; i < numDocs; i++) {
      Document d = new Document();
      d.add(new StringField(strMapper.names().indexName(), "str" + i, Field.Store.NO));
      d.add(new LongField(lngMapper.names().indexName(), i, Field.Store.NO));
      d.add(new DoubleField(dblMapper.names().indexName(), Double.valueOf(i), Field.Store.NO));
      writer.addDocument(d);
    }

    reader = SlowCompositeReaderWrapper.wrap(DirectoryReader.open(writer, true));
  }