### Question:
RSet extends RCollection { @Override public KeyIterator getKeyIterator() throws KitDBException { try (CloseLock ignored = checkClose()) { return getKeyIterator(HEAD_B); } } protected  RSet(DB db); List<byte[]> pop(String key, int num); void remove(String key, byte[]... values); boolean contains(String key, byte[] value); void addMayTTL(String key, int ttl, byte[]... values); void add(String key, byte[]... values); @Override void delete(String key); @Override KeyIterator getKeyIterator(); void deleteFast(String key); @Override @SuppressWarnings("unchecked") RIterator<RSet> iterator(String key); @Override int getTtl(String key); @Override void delTtl(String key); @Override void ttl(String key, int ttl); @Override boolean isExist(String key); @Override int size(String key); @Override Entry getEntry(RocksIterator iterator); final static String HEAD; final static byte[] HEAD_B; final static byte[] HEAD_V_B; }### Answer:
@Test public void getKeyIterator() throws KitDBException { String head = "getKeyIterator0"; RSet set = db.getSet(); int num = 100; Set<String> keys = new HashSet<>(); try { for (int i = 0; i < num; i++) { int num2 = 1000; keys.add(head + i); for (int i1 = 0; i1 < num2; i1++) { set.add(head + i, ("hello world" + i).getBytes()); } } Set<String> keys2 = new HashSet<>(); try (KeyIterator keyIterator = db.getSet().getKeyIterator()) { while (keyIterator.hasNext()) { String key = keyIterator.next(); keys2.add(key); set.delete(key); } } Assert.assertTrue(keys.containsAll(keys2)); Assert.assertTrue(keys2.containsAll(keys)); } finally { for (int i = 0; i < num; i++) { set.delete(head + i); } } }