@Test
  public void testScan_singleEntryInRepository_assertSingleKey() {
    final Tx tx1 =
        TestUtils.makeMessage(
            TxMessageType.IMF, "12345", "", "*****@*****.**", "*****@*****.**", "", "", "");
    final Tx tx2 =
        TestUtils.makeMessage(
            TxMessageType.IMF, "67890", "", "*****@*****.**", "*****@*****.**", "", "", "");

    final Collection<Tx> txs = Arrays.asList(tx1, tx2);

    final Exchange exchange = new DefaultExchange(context);
    exchange.getIn().setBody(txs);

    final ConcurrentJPAAggregationRepository repo =
        new ConcurrentJPAAggregationRepository(notifDao);

    repo.add(context, "12345", exchange);

    repo.remove(context, "12345", exchange);

    final Set<String> ids = repo.scan(context);

    assertEquals(1, ids.size());
    assertEquals(exchange.getExchangeId(), ids.iterator().next());
  }