@Test
public void testCommit() throws Exception {

    TransactionId transactionId = transactionServer.start("das-test", "MySqlSimple", Hints.hints());
    Assert.assertEquals(1, transactionServer.getCurrentCount());
    String r = transactionServer.doInTransaction(transactionId.getUniqueId(),()->"OK");
    Assert.assertEquals("OK", r);
    transactionServer.commit(transactionId.getUniqueId());
    Assert.assertNotNull(transactionId);
}