IndexWriter iw = new IndexWriter(indexDir, newIndexWriterConfig(TEST_VERSION_CURRENT, new MockAnalyzer(random())));
FacetsConfig config = new FacetsConfig();
for (int i = 0; i < 10; i++) {
Document doc = new Document();
doc.add(new FacetField("a", Integer.toString(i)));
iw.addDocument(config.build(taxoWriter, doc));
}
DirectoryReader r = DirectoryReader.open(iw, true);
DirectoryTaxonomyReader taxoReader = new DirectoryTaxonomyReader(taxoWriter);