final byte[] a = { 'a' };
final byte[] b = { 'b' };
// start a tx1, add a change A and commit
Transaction tx1 = txManager.startShort();
Assert.assertTrue(txManager.canCommit(tx1, Collections.singleton(a)));
Assert.assertTrue(txManager.commit(tx1));
// start a tx2 and add a change B
Transaction tx2 = txManager.startShort();
Assert.assertTrue(txManager.canCommit(tx2, Collections.singleton(b)));
// start a tx3
Transaction tx3 = txManager.startShort();