public void testAckOnlyCreation() throws BlockedTooLongException, InterruptedException {
    NewPacketFormat npf = new NewPacketFormat(null, 0, 0, NEW_FORMAT);
    PeerMessageQueue pmq = new PeerMessageQueue();
    SessionKey s =
        new SessionKey(
            null,
            null,
            null,
            null,
            null,
            null,
            null,
            null,
            null,
            new NewPacketFormatKeyContext(0, 0));

    NPFPacket p = null;

    // Packet that should be acked
    p = new NPFPacket();
    p.addMessageFragment(
        new MessageFragment(
            true,
            false,
            true,
            0,
            8,
            8,
            0,
            new byte[] {
              (byte) 0x01,
              (byte) 0x23,
              (byte) 0x45,
              (byte) 0x67,
              (byte) 0x89,
              (byte) 0xAB,
              (byte) 0xCD,
              (byte) 0xEF
            },
            null));
    assertEquals(1, npf.handleDecryptedPacket(p, s).size());

    Thread.sleep(NewPacketFormatKeyContext.MAX_ACK_DELAY * 2);
    p = npf.createPacket(1400, pmq, s, false);
    assertEquals(1, p.getAcks().size());
  }