Document doc = new Document();
// create as many files as possible
doc.add(newField("c", "val", Store.YES, Index.ANALYZED, TermVector.WITH_POSITIONS_OFFSETS));
writer.addDocument(doc);
// Adding just one document does not call flush yet.
assertEquals("only the stored and term vector files should exist in the directory", 5 + extraFileCount, dir.listAll().length);
doc = new Document();
doc.add(newField("c", "val", Store.YES, Index.ANALYZED, TermVector.WITH_POSITIONS_OFFSETS));
writer.addDocument(doc);