Set<String> files = new HashSet<String>();
for (String file : dir.listAll()) {
dir.copy(dirCopy, file, file, IOContext.DEFAULT);
files.add(file);
}
dirCopy.sync(files);
// Have IW kiss the dir so we remove any leftover
// files ... we can easily have leftover files at
// the time we take a copy because we are holding
// open a reader:
new IndexWriter(dirCopy, newIndexWriterConfig(TEST_VERSION_CURRENT, new MockAnalyzer(random()))).close();